THE OHIO TURKEY INDUSTRY. Robert E. Cook Chairman, Department of Poultry Science

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2 CONTENTS The Ohio Turkey Industry, by Robert E. Cook Recent Progress in G-enetic Improvement of Turkeys, by Karl E. Nestor and Philip A. Renner * Efficient Use of Turkey Males, by Keith I* Brown... *... 5 Semen Quality and Fertility of Turkeys, by Karl E. Nestor, Keith I. Brown, and Nikola Bachev... 8 Relative Contribution of Males and Females to Reproduction of Turkeys, by Karl E. Nestor Egg Traits and Reproduction in Turkeys, by Karl E. Nestor and Keith I* Brown.. * *.. Improving Reproduction of Turkeys, by Karl E. Nestor Ovum Production : A Short Review, by Wayne Bacon... * Force Molting Turkey Hens for a Second Season of Egg Production, by Karl E. Nestor and Keith I. Brown. *.. 28 Effects of Light on the Circulating Levels of Estrogens, Corticosterone, Calcium, and Free Fatty Acids in Adult Female Turkeys, by Keith I. Brown...*...* The Effects of Temperature Programmed Feeding and Light Intensity on Growing Turkeys, by S. P. Touchburn and. L. Bacon....* 3& Feeding the Breeder Turkey. I* Out-of -Season Hatching Egg Production, by S, P. Touchburn ij.6 Feeding the Breeder Turkey. II* Unidentified Reproductive and Progeny Growth Factors, by S. P. Touchburn, E. 0. Naber, and R. D. M, Silva * Feeding the Breeder Turkey. III. A Review of the Recent Literature, by S. P. Touchburn.«*.**,«.*.***. $l\. Effect of Selecting Turkeys for Resistance to Cold Stress, by Karl E* Nestor, Keith I. Brown, and Nikola Bachev Recent Findings in Mycoplasma Meleagridis Research, by Y. S. Mohamed and E. H. Bohl...* The Effects of Antibiotic Combinations on the Growth, Feed Conversion, and Mortality of Turkeys, by S. P. Touchburn, K. E* Nestor, and Y. S. Mohamed New Dimensions in Electric Brooding, by James W. Marquand Turkey Management Procedures at OARDC, by Philip A. Renner /68-3M ll).

3 THE OHIO TURKEY INDUSTRY Robert E. Cook Chairman, Department of Poultry Science The Ohio turkey industry is growing at a rapid rate and current indications are that this growth will continue. Ohio r s location is ideal from the standpoint of being close to market centers, having a surplus of feed grains, and having an excellent transportation system to permit the movement of feed and turkeys to market* With surplus feed grains, the Ohio turkey industry should be one of the most efficient industries in the country if it is organized in the proper manner. The industry is organizing in an integrated manner to take advantage of our unique location* The industry is making two major adjustments from a production standpoint. These include the trend toward year-round production and complete confinement rearing of all turkeys produced. It is anticipated that the industry will continue to move rapidly toward adopting these two practices. The staff members of the Department of Poultry Science at the Ohio Agricultural Research and Development Center and The Ohio State University are interested in helping a sound turkey industry to grow and develop. Members of the turkey industry are encouraged to consult with our faculty members and specialists in the various areas of poultry. We are sincerely interested in helping you solve your problems and we hope that this Turkey Research Summary will be of value to you in conducting your business.

4 RECENT PROGRESS IN GENETIC IMPROVEMENT OP TURKEYS Karl E. Nestor and Philip A. Renner Department of Poultry Science Better breeding and better knowledge of nutrition and management provided by agricultural research have helped turkey producers grow turkeys more efficiently and offer consumers a more desirable product. "What recent progress has been made in the genetic improvement of turhe 73? Three strains were selected to represent the modern medium white turkey, the modern large white, and the large white of 10 years ago. A comparison of these three strains should give a measure of the genetic improvement which has been made, as well as point out some of the weaknesses of modern turkeys. The modern medium weight white turkeys were represented by the Wrolstad strain. Modern large whites were represented by a randombred control strain developed at the Research Center in 1966 from two elite lai ge white strains. A randombred control strain established in 1957 was representative ct tno past turkey. This strain was developed by crossing four strains of lai?ge white turkeys which were popular at the time it was established, The randombred control has been maintained by randombreeding without selection for any trait for the past 10 years. Therefore, it should be genetically similar to turkeys produced 10 years ago. A paired mating system was used in which one male was artificially mated to one female. Data on reproduction were obtained on 36 hens of each of the three strains of turkeys compared. Hens in this study were restricted to a 6-hour day for an 8-week period prior to lighting for egg production. At approximately lj.0 weeks of age, they were given 111 hours of light. The strains were intermingled in pens. Pai7 7 ly i at) id gains have been made in egg production during the past 10 years. Both modern strains produced more eggs than the large white turkey of the past (Table 1). For the large whites, the gain averaged 1.8 eggs per hen per year for a 180-day laying period. The average gain in egg production for the Wrolstads amounted to only 0.6 egg per hen per year. More emphasis has apparently been placed on egg production in large whites than in medium whites, Egg weight of the modern large whites increased $.2 grams per egg over the 10-year period. This was probably the result of the large gain in body weight accomplished during the same period. Egg weight was smaller in the Wrolstads than in the 1957 randombreds. Reproduction in medium whites was better than that of the other two strains (Table 1). Greater egg production, fertility, and hatchability of fertile eggs resulted in a larger number of poults being produced per hen in the medium whites than in the 1957 randombreds* The modern large white hens produced more poults than ""he 1957 randombrels as the result of higher egg production* This superior egg

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6 production overcame the effects of lowered fertility and hatchability of eggs laid by the modern large whites. Since turkeys are meat birds, growth rate and body conformation are extremely important. Body weights were measured on the three strains at 8, 16, and 21+ weeks of age and on breeders when the females attained an egg production of approximately 5 percent. Body conformation measurements were made at 21+ weeks of age. Body weights of the modern large whites (1966 randombreds) were much greater than the body weights of the 1957 randombreds in both sexes (Table 2). A gain of 6.7 pounds has been made by commercial breeders since 1957«This is a gain of 0*7 lh. per year. Similar values for females were 1+ Ib. and 0.1+ lb., respectively. The Vrolstads were heavier than the 1957 randombreds at 8 weeks of age. At 16 weeks of ages, however, the males had the same average weight and the Wrolstad females were slightly smaller. By 21+ weeks, Wrolstad males and females were smaller than the 1957 randombreds. This is probably the result of selecting for early development. This selection has overcome the effect of the smaller egg size on early development in the Wrolstad strain. Based on actual measurements, shank length, keel length, and body depth were largest in the 1966 randombreds and smallest in the Wrolstads (Table 2)* However, there were large differences in body weight. Table 3*--Body Conformation Measurements in the Three Strains Adjusted for Differences in Body Weight. Strain Shank Length Body Measurement at 21+ Weeks"* Keel Body Length Depth Breast Width Males Wrolstad 1966 Randombred t Randombred Wrolstad 2,30 FemalesL Randombred 1957 Randombred ^Measurements were adjusted for differences in body weight by dividing the body measurements by the cube root of body weight.

7 Previous research has shown that a linear measurement of the body changes in proportion to the cube root of body weight* After this adjustment was made, the measurements of skeletal size were largest in the 1957 randombreds and smallest in the Wrolstads. These results suggest that part of the gain in body weight in the modern large white has been accounted for by factors other than increase in skeletal size* The Wrolstads are characterized by short shanks and small body measurements. Breast width exhibited a different relationship between the three strains. On the basis of actual measurements (Table 2), the breast was widest in the 1966 randombreds and narrowest in the 1957 randombreds. However,, when the differences in body weight were considered, the relative breast width was greatest in the Wrolstads and smallest in the 195>7 randombreds (Table 3)* Thus, it appears that more emphasis has been placed on breast width in the Wrolstads than in the large whites. In both modern strains, breast width has increased more rapidly than body weight. In the future, more emphasis will likely be placed on improving egg production and reproductive ability. Continued advances in growth rate and body conformation will probably also be made.

8 EFFICIENT USE OF TURKEY MALES Keith I. Brown Department of Poultry Science At the present time turkey hatching egg producers keep 125 toms for each 1000 hens housed. At 32-31]. weeks of age, the investment per large torn is approximately $7* The additional cost of maintaining these toms for 18 more weeks is conservatively estimated to "be $5* for a total cost of $12 per torn or $l 00 per 1000 hens housed. This comes to a cost of $1.50 per hen or $0.02 per egg produced. Obviously,, if the number of toms required for insemination can be reduced, substantial savings can be realized. The number of males required may be reduced in three ways. The first is to select males for high volume, high quality semen. Research at OARDC has shown that there is a highly significant positive correlation (r= 0.26) between Table 1.--Effect of Collection Interval on Semen Characteristics. Collection Interval Volume (ml.) No. Sperm per Ejaculate (Bill.) No. Sperm/ ml. (Bill.). % Bent Sperm 2 day O.lSa 1.3?a a 3 day 0.27b 1.95b ha U day 0.28b 2.3Ub Ob 6 day 0.22a 1.97b b Means followed by different letters are significantly different at P <.01. Table 2. The Number of Sperm per 12-Day Period isith Four Different Collection Intervals. Collection Interval No. Sperm/12 Day Period (Bill.) 2 day 8.221*2 3 day U day day

9 Table 3.---Different Diluents Provide Fertility Equal to Undiluted Semen. Percent Fertility Week No. Dil. I II III S U U U.3 k $ Ave semen volume and concentration and a negative correlation (r= -O.ll _) between volume and number of abnormal spermatozoa. In addition, there is a significant positive correlation (r= 0.31) between volume and fertility. This means that if males are selected for high volume semen production, the semen per ejaculate will not only cover more hens but the average fertility will be improved. The second way to reduce the number of males required is to collect semen and inseminate every 3 days. This can be done, as shown in Table 1. There were as many spermatozoa per ejaculate and fewer bent sperm when collections were made every 3 or 4 days as when collections were made at 6-day intervals* More spermatozoa were produced per 12-day interval when semen was collected every 3 days than at'any other collection interval except the 2-day interval (Table 2)» However, the 2-day interval is not recommended because the tails of the toms become sore. The volume per ejaculate was significantly reduced (Table l). At the present time a hypothetical hatching egg producer with 6000 hens keeps 750 males. He collects semen and inseminates every 10 days* By dividing his hens into three flocks and milking all males every 3 days, he could inseminate at 9-day intervals and use only 2^0 males. A third way to reduce the number of toms required is to use a semen diluent. This can be done, as shown in Table 3. In this study, three different diluents were used and equal parts of semen and diluent were mixed* The hens were inseminated at 7-day intervals* The males used as a source of semen had been in semen production for 1L[. months* All three diluents gave fertility equal to undiluted semen* -6-

10 Commercial diluents are available now which allow a threefold dilution of semen* The proper use of such a diluent, along with 3-day collection intervals, makes it possible to reduce the number of males required for 6000 hens to 83 or one-sixth the number now being kept by most hatching egg producers. This would reduce the cost of maintaining males from $1. 0 per hen housed to $0.2 per hen housed* These savings are available now to the alert hatching egg producer* -.7-

11 SEMEN QUALITY AND FERTILITY OP TURKEYS Karl E. Nestor, Keith I* Brown, and Nikola Bachev Department of Poultry Science Semen evaluation is very important because most turkeys are artificially inseminated. If an accurate method was available to evaluate the fertilizing ability of turkey semen, semen from low fertility males could be discarded and higher fertility would be obtained. Two studies were conducted at the Research Center to determine the feasibility of evaluating turkey semen. In one study, semen volume and visual density were measured on semen samples taken periodically from each male throughout the reproduction season. Volume of semen produced was measured with a 0.25? cc syringe. Visual density was estimated by rating the semen samples from 0 to 5, with 0 being very watery samples containing few sperm and 5 being thick, viscous semen. The intermediate numbers were used for samples falling in between the two extremes in visual density. A semen index was constructed as follows: Semen Index = Visual Rating + (Semen Volume x 23.1). A second study was made to determine the relationship between semen volume, sperm concentration and percent abnormal sperm, and fertility. The semen traits were measured at the beginning of the season (January), near the middle of the reproduction period (March), and near the end of the reproduction period (June). Semen volume was determined as in the first study. Sperm concentration was measured by the use of a fluorometer. Unpublished data indicated that sperm concentration as determined by the use of a fluorometer was highly correlated with sperm concentration as determined by the more conventional haemocytometer method* Percent abnormal sperm was determined microscopically. Hens in both studies were inseminated biweekly throughout the laying period* No effort was made to keep constant the amount of semen inseminated per hen. However, the amount of semen inseminated per hen was excessive. Eggs were candled at 7 days of incubation and all eggs classified as infertile were broken and examined macroscopically for the presence of early dead germs. The averages of the semen measurements (volume, density, and index) for each male in the first study were correlated with the fertility obtained by the use of semen from that male. A total of 213 males from 6 strains of birds were included in the experiment. The correlation coefficients (r) obtained in this study are presented in Table 1* The square of the correlation coefficient (p2) measures the amount of variation in one trait which can be accounted for by variation in the other. Semen yield, visual density, and the semen index were similarly correlated with fertility. These correlation coefficients were slightly higher in strains exhibiting greater egg production (5 and 6). The square of the correlation coefficient (r 2 ) indicates that 10 to 12

12 Table 1. Correlation Coefficients (r) of Semen Traits and Fertility in Turkeys According to Strains. Traits Correlated Fertility 1+ 6 Av. r OrO Semen Volume and Fertility.21) **.1+9**.31**.0961 Visual Density and Fertility.22.37* ]**.1+5**.3!]**.1156 Semen Index and Fertility.2? *30.1?.29.57**.51**.35** *122 Semen Volume and Visual Density.32.1^9** **.69**.1^5** Table 2.--Correlation Coefficient Between Semen Traits and Fertility. Semen Trait Time of Measure 0-1). wk. 5-8 wk. Fertility 9-12 wk. 0-8 wk wk. Volume Concentration Abnormal Sperm January March June January March June January March June * v.22""".18* * -.17*.09.27**.25**.Oi ** *.21* **.26** * -.17*. 01

13 percent of the variation in fertility can be accounted for by variation in the semen traits observed* Little would be gained by the use of both semen yield and visual density, since they are correlated with each other and the semen index was only slightly more highly correlated with fertility than either volume of semen produced or the visual density of the semen. The results of the second study are summarized in Table 2. In this study, the fertility obtained was divided into various periods* The first period (0-1+ weeks) began in March. The March semen measurements were made late in March and just before the to 8-week period. The June semen measurements were made near the end of the 9 to 12-week period. The January semen volume was not closely correlated with fertility during any of the periods of measurement (Table 2). March semen volume was significantly correlated with fertility during the latter part of the reproduction season and with total fertility for the entire season. Similar results were obtained with the June semen volume but the correlation coefficients were not as high as with the March measurement. In the first study, semen volume was measured periodically throughout the laying season. The correlations observed in the first study were probably influenced more strongly by yield in the latter part of the reproduction season. Sperm concentration did not exhibit a close relationship with fertility in this study* Only one coefficient was statistically significant but 13 of 15 were positive, which indicates a positive relationship between sperm concentration and fertility. The percent abnormal sperm measured in January had little relationship to fertility. However, abnormal sperm measurements made in March and June were related to fertility late in the reproduction period and to fertility for the entire period (0-12 weeks). The relationship was negative, which indicates that as percent of abnormal sperm increases, the percent fertility decreases. The results of these two studies suggest that some improvement in fertility could be made by selecting toms on the basis of semen traits. This selection would have to be made about mid-way through the reproduction period because early semen measurements are not closely related to fertility. Semen traits and fertility are usually at their highest level early in the reproduction season. This suggests that when fertility is the highest, semen traits have very little influence. Culling low fertility males at mid-season would probably result in an increase in average fertility for the entire period. Semen volume would probably be the trait of choice as a selection criterion. This is one of the easiest semen traits to measure. Itnprovement in semen volume would increase the total amount of semen produced and would result in a fewer number of males being required to inseminate a given number of hens. -10-

14 RELATIVE CONTRIBUTION OP HALES AND FEMALES TO REPRODUCTION OP TURKEYS Karl E. Nestor Department of Poultry Science A large amount of research has been devoted to improving the fertilizing ability of turkey males. Since most turkey hens are artificially inseminated,, most of the emphasis has been placed on such things as improving the yield of high quality semen and the use of diluents to prolong the functional life of the sperm. Research has been conducted in many fields of study, including genetics, nutrition, physiology, and management to improve the performance of the turkey male* Is this emphasis on the male really justified? Should more research be devoted to the turkey female? An analysis was made of some data collected at the Research Center to answer these questions. Commercially, most turkey hens in multiplier flocks are inseminated with semen pooled from several males. To obtain similar conditions in this experiment, semen from groups of five males was pooled. There were 18 such male pools representing three strains of medium weight white turkeys. The semen from each male pool was used to inseminate four to six hens biweekly and data on reproduction were collected over a 6-week period near the end of the laying period. The data was broken down into two 3-w@@k periods in order to estimate the effect of season on reproduction. The relative effects of strains, male pools, females, and periods were determined and are given in Table 1* Differences among females Table 1. Relative Effect of Season, Strain, Male Pool, and Females on Reproduction in the Turkey* % of the Total Variation Accounted for: Source HatchabilityNumber of Poults Variation Fertility of Fertile Eggs Produced Per Hen Season Strains Male Pool 10.U U*0 Lh Females Total

15 contributed the greatest amount of variation in all reproduction traits. Only 10 percent of the total variation in fertility was accounted for by differences between male pools of semen. Season and strain had very little effect on reproduction in this study. The values shown in Table 1 are good only for the conditions of this experiment and therefore can not be applied generally. However, they point out that late in the laying period, females contribute more to variation in reproduction traits than males do whenever semen is pooled* Table 2, Percent Fertility Obtained with the Various Male Pools of Semen. Male Pool Strain No. of Females % Fertility * * 1 1* 1* * ; ; *9.U

16 Table 3» Variation Observed in Percent Fertility Between Hens Inseminated with One Male Pool. Hen No, U % Fertility U A great amount of variation was exhibited between the average fertility obtained with different male pools (Table 2). The percent fertility ranged from 28*2 to 9^.9 in the 18 male pools. However, a much larger variation was evident between hens inseminated with the same male pool. A good example of this is presented in Table 3 for one male pool. The percent fertility of the hens ranged from 13*2 to 97*9 when the same semen was inseminated. It is obvious from the results of this experiment that more emphasis in research needs to be placed on improving the reproduction of turkey females 9 particularly late in the laying period.

17 TRAITS AND REPRODUCTION IN TURKEYS.!/ Karl E. Nestor and Keith I* Brown Department of Poultry Science Previous research conducted at the Center (Turkey Research 1966, Res. Summary 17:2l.-28) indicated the association of certain egg traits and hatchability of turkey eggs* Therefore, it was decided to determine the influence of length of lay on certain traits of turkey eggs and to determine the influence of these egg traits on reproduction. The egg traits measured included egg weight, shell weight, percent protein in yolk, wet weight of the yolk,, percent ash in yolk, weight loss after 7 days of incubation, dry weight of yolk, percent yolk, percent albumen, percent shell, and percent incubation weight loss. These traits were measured periodically throughout the season. Two strains of turkeys were used. One strain represented the modern commercial turkey (meat strain) and the other was a lighter strain which had been selected for increased egg production. Hens of both strains were brought into production in the last part of February when they were approximately \\2 weeks of age. Significant seasonal changes were observed in wet weight of yolk, percent ash in yolk, shell weight, weight loss after 7 days of incubation, percent yolk, percent albumen, percent shell, percent incubation weight loss, percent hatchability of fertile eggs, and number of poults produced per hen (Table 1). Strain differences were apparent in yolk wet height, egg weight, shell weight, weight loss after incubation, percent yolk, percent albumen, percent incubation weight loss, and number of poults produced per hen. The difference in shell weight between strains was due to the strain difference in egg weight, as there was no significant strain difference in percent shell* A significant interaction occurred between strain and season in the number of poults produced per hen. This indicates that the two strains differed in their rate of seasonal decline. It was apparent from the data that the meat-type birds tended to have lower initial fertility and hatchability but did not exhibit as fast a seasonal decline as the egg strain. Although the interaction of strain and season was not significant for either fertility or hatchability of fertile eggs alone, the effect was compounded so that the interaction was significant in number of poults produced per hen. The data of the egg strain were further analyzed to determine the phenotypic relationship between egg traits and hatchability and to determine the possibility of predicting hatchability and number of poults produced per hen by the use of egg traits. The egg line data were used because of the larger number of observations. i/supported in part by grants from the National Turkey Federation and Ohio Poultry Association. -Hi.-

18 Table 2 gives the phenotypic correlations between egg traits and hatchability and number of poults produced per hen* Wet weight of yolkj percent yolk^ 7-day incubation weight loss, and percent J-day incubation weight loss were negatively correlated with hatchability and number of poults* This means that as the egg traits increased in magnitude, percent hatchability and number of poults decreased. As shell weight, percent shell, and percent albumen increased, so did hatchability and number of poults produced per hen. Several egg traits were not included in the correlation analysis since they did not exhibit a seasonal change and therefore would not be correlated with the reproduction traits. A stepwise regression analysis was conducted on the data from the egg strain* In this analysis, traits were added one at a time and then a regression formula calculated for predicting reproduction traits* This analysis starts with the variable most closely correlated with the reproduction trait and then proceeds to the least closely Table 1. Influence of Season and Strain on Egg and Reproduction Traits* Trait Mar. Apr. May Month Jims July Aug. Sept. Strain Meat Egg % Protein Tolk lt U Wet Wb. Tolk (gm.) % Ash in Yolk la Egg Wb. (gm.) Shell Wt. (gm.) tlt U Wt. loss after 7 days Incubation (gm.) U Dry Wt. Tolk (gm. ) 2.7U U % Yolk lt -3 2 % Albumen % Shell % Incubation Wt. Loss U U li.lt It.lU 5It.lt lt It.ltl It.13 3 % Hatchability Fertile Eggs U2.8 ltlt-3 1 6U No. Poults Produced Per Hen ^Differences between months were highly significant (P <.01). ^Differences between strains were highly significant (P<.01). 3Differences between strains were significant (P<.05)*

19 correlated trait. After the addition of each.trait, the amount of variance in the reproduction trait, which was accounted for by all traits entered up to that point, was calculated. The significance of the addition of each egg trait to prediction of the reproduction trait also was determined* A total of 25 percent of the total variation in hatchability can be accounted for by the use of nine egg traits (Table 3). However, percent yolk, percent shell, and 7-day incubation weight accounted for 21 percent of the variance. Therefore, little was gained by use of the other six traits* In the case of number of poults produced per hen, percent shell and percent albumen were the most accurate predictors (Table 4)* It can be concluded that some egg traits are phenotypically correlated with reproduction traits in turkeys. Shell traits, wet weight of yolk, percent yolk, and percent albumen were more closely related to reproduction traits than the other egg traits studied* The phenotypic relationships presented in Table 2 result from a combination of the genetic relationship between the traits involved and a relationship resulting from environmental factors* It is impossible to accurately predict genetic correlations by the use of phenotypic correlations* Table 2.--Phenotypic Correlations Between Egg Traits and Hatchability and Number of Poults Produced Per Hen. Correlation with: Egg Trait Hatch. Fertile Eggs 1 No, Poults 1 Wet Weight Tolk % Ash in Tolk Egg Weight Shell Weight 7 Day Incubation Weight Loss % 1 Day Incubation Weight Loss % Shell '% Tolk % Albumen -.22** -,01;.11.30** ** -.30**.32** -.38**.30** -.20* -.08.Ok 3U*» -.27** -.25**.U3** -.27**.16* Indicates correlation was significantly different from zero (P<.0l).

20 Table 3.--Predicting Hatchability by Egg Traits* Trait (s) Amount of Variance Accounted for (%) Significance of Addition of Trait u. 5. * Yolk 1 + Shell Day Incubation Wb. Loss 3 + Albumen U + Wet Wb. Yolk 1U W- ** * U.S. N.S Egg Weight 2U.8 H* % 1 Day Incubation t. Loss 25-0 N.S % Ash in Yolk 25-0 N.S Shell Weight 25.2 N.S. * Indicates effect of addition was significantly, different from zero ^w Indicates effect of addition was significantly different from zero N.S. Indicates effect of addition was not significant. To determine the feasibility of use of egg traits as selection criteria for improving hatchability, work is in.progress to estimate the heritability of and genetic correlations among egg traits and hatchability* If the egg traits are highly heritable and have a close genetic relationship to hatchability, it would be possible to improve hatchability by selecting for improvement in the egg traits. -17-

21 Table U.--Predicting Numbers of Poults Produced Per Hen by Egg Trait. Amount of Variance Significance of Trait (s) Accounted for (%} Addition of Trait 1. % Shell 18.5 **l % Albumen 22.0 ** 3. u Day Incubation Wt. Loss 3 + $ 7 Day Incubation Wt. Loss U + Wet Wt. Tolk l».6 N.S. N.S. N.S Shell Weight 6 + % Ash in Tolk 7 + % Tolk 25.U N.S. N.S. N.S Egg Weight 25.6 N.S. #* Indicates effect of addition was significantly different from zero (P N.S. Indicates effect of addition was not significant.

22 IMPROVING REPRODUCTION OF ITJRKEYS Karl E. Nestor Department of Poultry Science Good gains in growth rate have been made by turkey breeders in recent years. Small advances have also been evident in egg production and number of poults produced per hen* The turkey still remains a poor reproducer, which results in high poult cost* Egg production and number of poults produced per hen are closely associated. Anything which will improve egg production will usually result in a greater number of poults being produced. There are several ways in which turkey breeders might improve egg production of turkeys* Among these are: (1) selection for increased e gg production alone; (2) selecting a line for increased egg production and a line for increased growth and crossing the two lines to obtain a desirable type offspring; (3) selecting for increased growth rate and increased egg production simultaneously; and (1 ) selecting for increased egg production for a few generations and then selecting for increased growth rate* One serious difficulty encountered by turkey breeders in improving reproduction is that they must remain competitive in growth rate* Since turkeys are used entirely for meat, turkeys which have good reproduction but do not grow fast are of little economical importance* Genetic studies at the Research Center have been devoted to testing the alternate means of improving turkey reproduction* A line was developed from a randombred control population by selecting only for increased egg production on the basis of the dam! s performance* The randombred population, which does not change genetically from generation to generation, was used to remove differences in generations due to unknown variations in the environment. The results of the first seven generations of selection are presented in Table 1, Selection greatly increased egg production in the egg line* This resulted from a reduction in the amount of broodiness and an increase in intensity of lay. The number of poults produced per hen also increased in the egg line* Very little change in growth rate was noted in the first four generations of selection in the egg line (Table 2). During this period, a gain of 11 eggs per hen was made in Si^-day egg production (Table 1). An additional gain of seven eggs per bird in the last three generations resulted in a great reduction in 2l,~week body weight. The apparent lack of gains in egg production in the egg line for the longer production periods (120 and 180 days) in the last three generations may be the result of a more efficient broody management system used in these generations* Since broodiness had been greatly reduced in the egg line, the better broody management would result in a greater increase in production in the control line than in the egg line* -19-

23 Table 1. Response to Selection for Increased Egg Production. Line Year Egg Production (Days) 8ii Days Days Days Clutches Broody Periods /8U Days /81; Days No./ Length No./ Length Hen (Days ) Hen (Days) % Broody Hens (8U Days) 2 No. Poults / Hen 8 wk. 12 wk. i ro o i Control U Egg U to )()[ U2 hh 38 Ul U h U U U i OU U ) Hi. 2 11* U li U * * U ^Expressed as deviation from control population, that went broody at least once.

24 Selecting only for egg production is a rapid means of improving egg production of turkeys» At the present time, however, it is unlikely that turkey breeders could place all of their emphasis on egg production for more than a very few generations and still remain competitive in growth rate. Rapid gains in growth rate are being made each year by commercial turkey breeders. This, along with the fact that growth rate declines after a few generations of selection for increased egg production, would greatly restrict the number of generations which a breeder could devote entirely to improving egg production. Selecting for increased growth rate after a few generations of selecting for increased egg production (alternate ij. given earlier) might be a way in which breeders could remain competitive and improve reproduction. This is assuming that all of the gain in egg production would not be lost by increasing the body weight. This possibility will be tested by developing a sub-line from the egg line based on selecting for increased growth rate. The egg line was crossed in 1966 with two commercial strains of large type whites. The results are given in Table 3. The cross of Kimber males with egg line females exhibited slight positive heterosis (i.e., the average of the cross was greater than the average of the two parental lines) in 8-week and 2l ~*week body weights. On the other hand, the cross of Williams males with egg line females resulted in Table 2. Effect of Selection for Egg Production on Growth Rate. Line Tear Males Females Body Wt. (Ibs.) Body Wt. (Ibs.) TTW.16 wk.2k wk. Fwk;16 wk. 2U wk. Control i ? k.o U.2 u.u h.$ U U U U 9.U Egg U «i *"* JL " * «JL * U ^Expressed as deviation from control population. -21-

25 negative heterosis. For the cross between a, meat strain, such^as the two commercials used, and an egg strain to be valuable commercially, the body weight of the cross should closely approach or even exceed the body weight of the larger parent. This was not the case when the Kimber and Williams strains were used as the male line. A new randombred control population was established from the _ Kimber and Williams strains of large whites. A sub-line (16-week line] of this population was initiated by selecting for increased 16-week body weight. The randombred control population and the 16-week line were crossed with the egg line in 196?. These same lines were also crossed with the Wrolstad strain which is representative of modern medium white turkeys. Very little heterosis was observed (Table!(.). This agrees with the results obtained in In both years, an attempt was made to use the same males in the cross as those used to produce the pure lines so that errors due to sampling of the males would be minimized. The results obtained from crossing indicate that little heterosis is exhibited in growth rate and, therefore, crossing is not a desirable method of improving both growth rate and reproduction performance. To determine the feasibility of selecting for increased body weight and increased egg production simultaneously, a second sub-line Table 3. Egg Line. -Effect of Crossing Two large Commercial White Lines with the Body Wt. (Pounds) 8 wk. 16 wk.2k wk. Shank Keel Body Breast Length Length Depth Width MATES Kimber Williams Egg Kimber x Egg Williams x Egg l* U 7.51* * EEMALES Kimber Williams Egg Kimber x Williams Egg1. xegg 1 U.62 1* * * -f.20 "* ob * *1 5.1* ^Expressed as deviation of the cross from the average of the two parental lines* A positive sign indicates positive heterosisj a negative sign suggests negative haterosis. -22-

26 Table ^.--Effect of Crossing Heavy White Lines mth the Egg Line, Body Wt. (Pounds) 8 wfc. 16 wk. 21; wfc. Shank Length Keel Length Body Depth Breast Width MALES Randombred Control 2 16 wk. line Egg line Wrolstad k.$ $ UO i ro Control x Egg 1 16 wk. x Egg Control x Wrolstad 16 wk. x Wrolstad ok *.6 -.k # J> It ? Oli FEMALES Randombred Control 2 16 wk. line Egg Line Wrolstad U k ? i Control x Egg 1 16 wk. x Egg 1 Control x Wrolstad 1 16 wk. x Wrolstad u ^Expressed as deviation of the cross from the average of the two parental lines, positive heterosisj a negative sign suggests heterosis. A positive sign indicates

27 was initiated from the randornbred control in the same generation as the 16-week line. Selection in this line is on the basis of a selection index which gives three times the emphasis to 16-week body weight as that given to 180-day e fco pro^ictjor. The results obtained in the first generation are presented in Table 5. Selection was effective in improving body growth rat^ and egg production Jn the index line. Body weight was improver, grc >tly in the 16-week line but egg production was reduced. It appears that inde: selection may be the most feasible means of improving botb fn^owth rate and egg production. However, the data presented in Table are based on only one generation of selection so the results are prelinif ary. Table. Effect of Selecting for Increased 16 Me. Body Weight Alone and for Both Increased 16 Wk. Body Weight and Increased Egg Production. Body Wt. (Pounds) 8 wk. 16 wk. 2U wk. Egg Production (No.) 8lf Days Days Days Randombred Control 16 wk. line - 1 Index line MALES FEMALES Randombred Control 16 wk. line 1 Index line k, V ^Expressed as deviation from randonibred control. -2k-

28 OVUM PRODUCTION: A SHORT REVIEW Wayne Bacon Department of Poultry Science This report is concerned with some of the information available concerning ovarian follicular development and the control of ovulation in turkeys, chickens, and quail* In small follicles, not yet undergoing rapid development, the very small ovum or egg yolk (2 mm* diameter) is surrounded by several layers of cells and membranes* Directly adjacent to follicles of this size is a single layer of cells called the granulosa cells. In small follicles, these cells are approximately twice as tall as they are wide and are very closely packed, with little space between them (12), The outer ends of the granulosa cells rest on a membrane, the basement membrane, which completely surrounds the ovum* This membrane is constructed of a relatively fine fibered and tightly woven material. It has a thickness of about 0*7 micron (1 micron = mm.). Several layers of cells called the thecal cells are on the outside of the basement membrane (6j 12)* This is the area where the ovum receives its blood supply* No blood vessels pass through the basement membrane* The blood enters this cellular area by small coiled arteries and flows into an area of large capillary spaces next to the basement membrane* The blood is then collected by a series of small venules into the outer layers of thecal cells and leaves by a few large veins on the surface of the follicle. Structural changes have been noted after a follicle begins rapid development* Rapid development has been defined as the ability of a follicle to deposit fat soluble dye in yolk material (3)* A graded distribution is usually found in the size of the follicles in rapid development in laying turkeys, chickens^ and quail. Rapid development starts in small follicles of about 5 "to 7 ^ * diameter in turkeys and chickens; in quail, it starts in follicles of about 2 to 3 mm. Rapid development lasts for about 13 to l days in turkeys (3) 9 1 to 9 days in chickens (!].), and 6 to 8 days in quail (2). During this period, the egg yolk or ovum reaches the size normally found in an egg. Two new regions, both at the junction of the granulosa cells and ovum, become apparent after a follicle has begun rapid development. The innermost region,, apparently arising from the ovum cell membrane by its being thrown into many deep folds, is the zona radiata. The appearance of the zona radiata coincides with the initiation of yolk deposition and the beginning of rapid development* It is probably associated with an essential part of the process of yolk deposition. The second new region is the perivitellin layer* This area is where a portion of the vitellin membrane, the membrane surrounding the yolk of the egg, is formed* It lies between the zona radiata and granulosa cells* Egg yolk contains about 1^8*7$ water, 32.6^ lipid, 16.6% protein, and 2*1^> carbohydrates and minerals (10)* Most of the protein and almost all of the lipid occur in lipoprotein complexes.

29 The yolk plasma contains one fraction, the low density lipoprotein, which accounts for 67$ of the total yolk solids. This fraction has been found to be composed of units of protein wrapped about a lipid core composed mainly of triglycerides (1). This fraction is made up of 80$ lipid and 2Q% protein. The yolk plasma also contains alpha, beta, and gamma levitins which are identical with serum albumen, serum beta glycoprotein, and serum gamma globulin, respectively (11). In summary, the avian egg yolk solids are mainly lipid and protein and 90$ of all solids occur in the dense granule and plasma low density lipoprotein complexes. The source of egg yolk protein is apparently the blood plasma. The levitins are identical with blood plasma proteins (11). Phosvitin has been isolated from the blood plasma of laying hens (1) 9 while lipid-protein complexes in the blood plasma and egg yolk plasma low density lipoprotein have been shown to contain identical units of protein (9) When egg yolk is centrifuged under high force, it can be separated into two main components, the dense granules, which settle to the bottom of the centrifuge tube, and the plasma, which remains in suspension. The dense granules, about the size of red blood cells, contain 23$ of the total yolk solids in the form of proteins, lipids, minerals, and virtually all of the yolk carbohydrates ( ) The proteins are of two types. Phosvitin, accounting for about 16$ of the total dense granule fraction, is a unique protein. It is composed of about ^0$ of the amino acid serine, all of which is chemically bonded to phosphorus (8). Virtually all of the egg yolk protein bound calcium is also associated with phosvitin. The second type of dense granule protein is found in complexes with lipids. Alpha and beta lipovitellins, 70$ of the dense granules, contain about 80$ protein and 20$ lipid. The lipid in this fraction is mainly phospholipid. When this protein is complexed with triglycides, it is less dense than the heavier lipovitellins and can thus be separated from them by centrifugation. Such a low density fraction has been isolated and reported to contain a greater amount of lipids and more triglycide than the lipovitellins. The process controlling the accumulation of yolk material in follicles undergoing rapid development is not well understood. Material is removed from the blood plasma^at the thecal cells. It must then pass through the basement membrane, granulosa cells, perivitellin area, and zona radiata before it is finally deposited in the follicle. In both blood plasma and egg yolk, the majority of this material is found in molecular complexes much too large to have passed intact through the several layers of cells and membranes. Thus, it is possible that considerable rearrangement of molecules occurs during deposition. Few information is desirable at this time to better understand the growth of the avian follicle and the control of ovulation. Such information will give the geneticist new tools to select the more desirable birds, will allow the nutritionist to design a more efficient ration, will enable the engineer to design better housing, and ultimately the farmer and consumer will benefit by more efficient production. A study concerning ovum growth and ovulation is being initiated at the Research Center* -26-

30 References 1. Augustyniak, J«,. G. Martin, and. H. Cook. 1961}.. Characterization of lipovitellenin components and their relation to low density lipo protein structure* Biochem. Biophys. Acta. 8J+: Bacon,» Observations on ovarian follicular growth and maturation in Coturnix quail. Unpublished. 3* Bacon,. and P. L. Cherms Ovarian follicular growth and maturation in the domestic turkey. Poultry Sci. (in press). L.. Bacon,. and J* H. Skala Ovarian follicular growth and maturation in laying hens and the relation to egg quality. Poultry Sci» (in press). 5«Burley, R.. and * H. Cook Isolation and composition of avian egg yolk granules and their constituents and lipovitellins. Can. J. Biochem. Physiol. 39: G-uzzal, E Histological studies on the mature and postovulation ovarian follicle of fowl. Acta. Vet. Acad. Sci. Hung. 16: * 7. Heald, P. J. and P. M» McLachlan Isolation of phosvitin from the plasma of the laying hen. Biochem. J* 87: Heald, P. J. and D* Pohlman* Amino acid incorporation by microsomal fractions from the liver of the domestic fowl. Biochem. Biophys. Acta. 123: 390-i Schjeide, 0* A., J. ilkens, R. G. McCandless, R. Munn, M. Peterson, and E. Carlson. 1963* Liver synthesis, plasma transport, and structural alternations accompanying passage of yolk proteins. Amer. Zool. 3 : Sturkie, P. K Avian physiology. Cornell Univ. Press, Ithaca, N. Y. 2nd Ed., pp. l lj.7-51l{ Williams, J Serum proteins and the livetins of hen! s egg yolk. Biochem. J. 83: Wyburn, G* M*, R. N. C. Aitken, and H. S. Johnston The fine structure of the zona radiata of the fowl*s ovum. J. Anat. 99: -27-

31 FORCE MOLTING TURKEY HENS FOR A SECOND SEASON OF EGG PRODUCTION Karl E. Nestor and Keith I. Brown Department of Poultry Science A large cost is involved in growing turkeys until they reach the age of reproduction. If turkeys could be kept, with desirable results, for a second laying period after a short nonproductive (rest) period, large savings in costs and increased profits would result. Previously published research work on force molting of turkeys is conflicting* Earlier work indicated that force molting and allowing a short period of rest ( weeks or less) resulted in unsatisfactory performance during the second laying period. Egg production and other reproduction traits were usually lower in the second laying period. This reduction was great enough to make a second laying period uneconomical* However, a recent reports/indicated that when medium weight hens were given a 12-week rest period between the two laying periods, egg production was higher in the second laying period. This resulted in a larger number of poults being produced per hen during the second season* The purpose of this experiment was to determine the economic feasibility of force molting turkeys for a second season of egg production and to determine if selection, based on the first season T s performance^ could be used to improve the results obtained during the second * Three strains of medium weight white turkeys were force molted after they had been in egg production for 28 weeks. The strains did not differ in their response to the treatments and so the data for all three were combined. In the first season, the hens were restricted to a 6-hour light day for 8 weeks before bringing them into production at approximately l 2 weeks of age with llj. hours of light daily beginning February 1, The hens were moved to a different house on September 1 and were force molted 1 week later by the combination of three simultaneous treatments: (1) removal of water for a 2l+~hour period, (2) removal of feed for a it-8-hour period, and (3) light restriction to a 6-hour day* Egg production ceased within 7 days and a noticeable molt was evident 2 weeks after initiation of force molting* After 6 weeks of light restriction, the hens were again given llj. hours of light daily. Egg production for the 12-week period beginning on the date the first egg was laid was compared with a like period in the first season* The number of days required from lighting until the first egg was used as a measurement of responsiveness to light stimulation. I/Van Krey, H. P., A* T* Leighton, Jr., and D* D* Moyer* 196?. Force Molting of Turkeys to Obtain a Second Season of Egg Production* Abstract, Poultry Sci. 1+6:

32 Table 1* Body Weight, Egg Production, and Reproduction Traits in the First and Second Seasons of Production* No* Hens Body Davs Wt. at E 8S Prod * < N ') to %0fo Hens First Prod. All That Egg (kg.) Hens Laid % Non- Layers First Season i Second Season No. Hens E SS Wt. % (gm.) Fertility Hatch.. of F.E. No. Poults/ Hen First Season Second Season Comparisons of various reproduction traits obtained over an 8-week period at the beginning of each season were made. Males in their first season of semen production were used to inseminate the hens in the two age groups. Egg production, fertility, hatchability of fertile eggs, and number of poults produced per hen were all significantly (P<T*01) reduced in the second period of production (Table 1)* Body weight, egg weight, and days required from lighting to laying of the first egg were greater in the second period of production than in the first* Twelve percent of the hens failed to return to lay in the second season. The effects of age of hens, houses, and season of year were compared in this experiment* However, the second laying period occurred during a cooler, more favorable season of the year for egg production* Therefore, this factor was probably not responsible for the reduced egg production during the second period of lay. Noticeable differences were not apparent previously in the level of egg production obtained in the two houses involved in this experiment* Therefore, it is not likely that house effects were responsible for the lowered egg production during the second season* -29-

33 Table 2. Correlation Coefficients Among Various Traits in the First and Second Seasons of Production* No. Traits Correlated r 1 Body weight (first and second seasons) 86** 2 Egg production (first and second seasons).28* 3 Egg weight (first and second seasons) 79 WW k Fertility ^ (first and second seasons) *23^ 5 Hatchability of fertile eggs (first and second seasons) «23* 6 Number of poults per hen (first and second seasons).1 7 Body index and egg production index *30** 8 Egg production and fertility %0, (first season).3^"" 9 Egg production and hatchability of fertile eggs (first season).32** 10 Egg production and hatchability of fertile eggs ^ (second season) *2 * 11 Egg production and number of poults per hen (first season) *7l ** 12 Egg production and number of poults per hen (second season) *5^Hc 13 Egg production (first season) and number of poults per hen (second season) «3lj-** 111 Fertility and hatchability of fertile eggs (first season) «6ij.* H * > 15 Fertility and hatchability of fertile eggs (second season) 27* 16 Fertility and number of poults per hen (first season) Fertility and number of poults per hen (second season) $!** 18 Fertility (first season) and number of poults per hen (second season)»2l * 19 Hatchability of fertile eggs and number of poults per hen (first season).79** 20 Hatchability of fertile eggs and number of poults per hen (second season) *61 ** Indexes were constructed for egg production by subtracting the second season value from the first season value and adding a constant. Body weight indexes were obtained as follows: second season value «"** first season value + constant. -30-

34 The poor reproduction obtained in the second laying period may have resulted from the hens not having a rest period of adequate length after the relatively long period of lay in the first season. More desirable reproductive performance might be obtained by initiating the molt after a shorter length of lay in the first period and by allowing a longer period of rest. To test this, a group of hens will be force molted by 9-week light restriction after a 16-week laying period* Correlation coefficients were calculated within lines between various traits in the first and second periods of production. This was done to predict whether selection based on the first season's performance would improve the results obtained in the second period. Body weight, egg production, egg weight, fertility, hatchability of fertile eggs, and number of poults per hen were all positively correlated at a significant level between the first and second seasons, (Table 2)* However, only body weight and egg weight exhibited correlations large enough so that selection practiced on the basis of the first season! s results could greatly influence the second season! s performance* The body weight and egg production indexes were correlated significantly* This indicates that the greater the gain in body weight during the second laying period, the greater the reduction in second season egg production* Egg production, fertility, hatchability of fertile eggs, and number of poults per hen in the first season were not closely related with number of poults produced in the second season. Under the conditions of this experiment, force molting to produce a second season of egg production would not be profitable, even if only the best producing hens in the first season of lay were selected*

35 EFFECTS OF LIGHT ON THE CIRCULATING LEVELS OF ESTROGENS, CORTICQSTERQNE, CALCIUM, AND FREE FATTY ACIDS IN ADULT FEMALE TURKEYS Keith I. Brown Department of Poultry Science Since Rowan f s initial discovery (18) that increasing day length artificially in late winter induces premature gonadal activity in migratory birds, it has been demonstrated repeatedly that day length exerts a major influence on the reproductive function of birds. This photosexual response has been used effectively in controlling reproduction in domestic birds* Excellent general reviews on photoperiodism are available for domestic birds (6) and for other birds (5, 21). Experiments devoted to effects of light regimes on preconditioning and on subsequent reproduction of turkey hens have been conducted by Harper and Parker (8, 9, 10); Marr et al. (13); Leighton and Shoffner (12); Wilson, Ogasawara, and Asmundson (19); Marsden, Cowen, and Lucas (llj.); McCartney et al. (17) S &ftd Marsden and Lucas (15>). Marshall (16) described three successive phases in the sexual cycle: regeneration (sudden loss and subsequent recovery of breeding function), acceleration (characterized by sex hormone production and gametogenesis), and culmination (involving ovulation and insemination)* This study was confined to the 3-week period before the onset of lay when turkeys are stimulated into egg production (llj. hours of light, 10 hours of dark), which is equivalent to the acceleration phase. Bacon, Cherms, and McShan (1, 2) have shown recently that when the female turkey comes into production, the levels of gonadotrophins in the pituitary are drastically reduced (ten-fold reduction). A more complete picture depicting the changes in the internal physiology of the bird at this stage requires measurement of estrogens. In addition to their profound action on the reproductive process,, estrogens play a pivotal role in the regulation of lipid and calcium metabolism in the female bird in this particular period of high metabolic demand. The involvement of the adrenal cortex in regulating intermediary metabolism, mineral metabolism, stress, reproduction, and gonadal interactions suggests its participation in the periodic fluctuations (cycles) in the environment. These periodic fluctuations in birds constitute superb examples of the efficacy of the phenomena denoted by Witshci (20) as correlative adaptations in the avian species at the time of reproduction* Hahn (7) demonstrated the coincidence of For turkeys, the accelerator of the sexual cycle is light* In the acceleration phase, the bird has attained a physiological condition in which the neuroendocrine apparatus becomes active and secretion of gonadotrophins begin. These, in turn, activate the gonads and cause secretion of sex hormones, accompanied by gametogenesis, gross hypertrophy of the oviduct, and development of accessory sexual characteristics. Toward the end of the acceleration phase, the testes in the male contain massive numbers of spermatozoa and the female is ready to begin the final rapid development of follicles which will end in ovulation and oviposition. -32-

36 adrenocortlcal activity and gonadal activity in the mallard* Similarly, the adrenal cortex of the starling has an annual period of cortical hypertrophy which, in males, is concurrent with spesmatogensis (4). Bulbring (3) found the requirement for cortical extract to maintain life for a definite period time in the spring period of sexual activity to be much greater than during nonbreeding seasons in drakes* The purpose of this study was to correlate possible light-induced variations in circulating estrogens with changes in physiological circulating levels of corticosterone, calcium, and total free fatty acids which will contribute to an integrated picture of the overall changes induced by light* Procedure A total of 128 Williams bronze female turkeys reared under restricted light conditions (6 hours of light, lo hours of dark) were distributed equally (16 birds per pen) in 8 pens, and the light increased (llj- hours of light, 10 hours of dark; at 30 weeks of age* The first day under the increased light regime constitutes day 1* However, a day before the turkeys were put on the stimulatory light regime (day 0j, heparinized blood samples from the heart were collected (100 ml*/bird) from the 16 birds in pen 1* Subsequent blood samples were collected serially from pens 2, 3* l±y 5* 6, 7* and 8 on days 3> 6, 9* 12, 15>«18, and 21, respectively* Thus, in this experimental design (although from different turkey hens) blood samples were available on every 3**d day for estrogen, corticosterone, plasma calcium, and plasma free fatty acids determinations for the entire 21-day period before onset of lay* Results and Discussion In the period of 21 days before the start of lay, there was a highly significant (P<-*01) increase in estrone, estradiol -1?B, corticosterone, calcium, and free fatty acids* In the same period, however, blood concentration of estriol showed a highly significant (P< *01) decrease* These data demonstrate for the first time that blood concentrations of estrone rise in the period (21 days) of rapid ovarian development* Secondly it is shown that a highly significant correlation (r~0*33; P-<C*01) exists between estrone and estradiol -1?B concentrations* The latter implies that, regardless of light regime, the concentrations of estrone and estradiol -17B are closely related* These data show that during the reproductively quiescent period, the bird eliminates the formation of more potent estrogens by synthesizing large amounts of estriol* When the birds are lighted for production, the more potent estrogens, estrone, and estradiol -17B are formed in larger amounts* There was a significant increase in corticosterone concentration during the first 3 days of 14 hours of light* It returned to base levels by the 6th day and then increased again as the estrone and estradiol -17B increased* The sudden increase in corticosterone to day 3 ttiay be attributed to the stress inherent in extended activity due to the longer light -33-

37 periods. After the birds become adapted to the long day, corticosterone levels return to base levels. Then, as estrone and estradiol increase, they either increase the secretion of corticosterone or decrease its utilization. Thus corticosterone rises to a peak by the 21st day. Both calcium and free fatty acids (FPA) were significantly increased from day 3 on. There were significant correlations between plasma calcium and FPA (r=0.1^5k calcium and estrone (r=0.l4.0), and PPA and estrone (r^o.i^o). The above data contribute to an understanding of the physiological mechanisms involved in egg production. Further studies need to be conducted throughout the reproductive season and at different times of the 2l -hour egg production cycle. References 1. Bacon,., F* L. Cherms, and. H. McShan. 1966a* Gonadotrophin assay of cephalic and caudal lobes of anterior pituitary from growing turkeys. British Poul. Sci. 7:1. 2. Bacon,., P. L. Cherms, and. H. McShan. 1966b. Pituitary weight and gonadotrophin concentration, body weight, and ovarian weight in growing and mature female turkeys exposed to different light regimens. British Poul. Sci* 7: Bulbring, E. 1937* Relation between size of testes and requirement of cortical extract in adrenalectoraized drakes. J* Physiol. 91: Burger, J * Cyclic changes in the thyroid and adrenal cortex of the male starling and their relation to the sexual cycle. Am. Nat. 72: * Parner, D* S. 1959* Photoperiodism and related phenomena in plants and animals* Amer. Assoc. Adv. Sci., ashington, D. C. 6. Praps, R* M. 1959* In Photoperiodism and related phenomena in plants and animals. Amer. Assoc. Adv. Sci., ashington, D. C. 7. Hahn, E i -7* Sexual behavior and seasonal changes in the gonads and adrenals of the mallard. Proc. Zool. Soc. London* 8. Harper, J. A. and J. E. Parker. 1957* Changes in seasonal egg production of turkeys induced through controlled light exposure and force molting. Poultry Sci. 36: Harper, J. A* and J. E. Parker. I960. Effect of restricted light and hormones on subsequent egg production of winter hatched turkeys* Poultry Sci* 39: *.-

38 10* Harper, J* A. and J. E. Parker* Effect of fall hatch date and length of light restriction on photoperiodic response of turkey females. Poultry Sci* l±.l :i]_93-l; Leighton, A. J. and R. N. Shoffner. 196la, Effect of light regime and age on reproduction in turkeys* I. Effect of li _, 2l\. hr. and restricted light treatment. Poultry Sci. L.0:86l. 12* Leighton, A. J. and R* N* Shoffner. 196lb* Effect of light regime and age on reproduction of turkeys. II. Restricted vs. unrestricted light. Poultry Sci. 14.0: Marr, J. E., P. N* Garland, Jr., J. L. Milligan. and H. L. Wilche* 1956* Effect of controlled light during the growing period upon subsequent performance of breeder turkeys* Poultry Sci* 35:1156* ll^. Marsden, S* J*, N. S. Cowen, and L. M* Lucas. 1962* Effect of gradual and abrupt lengthening of photoperiod on reproductive response of turkeys* Poultry Sci. I.l:l861j.. 1^* Marsden, S* J* and L* M. Lucas* 1961).. Effect of short-day or low intensity light treatments on reproduction of fall hatched turkeys in two environments. Poultry Sci* 14.3 "14-35* 16. Marshall, A* J* I960* Breeding seasons and migration. In The Biology and Physiology of Birds II. A* J. Marshall, Ed. 17. McCartney, M. G*, V. L* Sanger, K* I. Brown 5 and V* D. Chamberlin. 1961* Photoperiodism as a factor in the reproduction of the turkey* Poultry Sci. lj-0:368: Rowan. * 1925>«Relation of light to bird migration and developmental changes. Nature. 19* Wilson, * 0*, F* X. Ogasawara, and U* S* Asmundson Artificial control of egg production in turkeys by photoperiods * Poultry Sci* I l:ll68* 20* Witschi, E* 1959* Endocrine basis of reproductive adaptations in birds* Comparative Endocrinology. Asbrey Gorbman, Ed. Proc., Columbia Univ. Symposium on Comparative Endocrinology. 1958* 21* Wolf son, A* 1959* Photoperiodism and related phenomena in plants and animals, Amer, Assoc. Adv. Sci*, Washington, D. C. -35-

39 THE EFFECTS OF TEMPERATURE PROGRAMMED FEEDING AND LIGHT INTENSITY ON GROWING TURKEYS S* P. Touchburn and V* L. Bacon Department of Poultry Science The effects of seasonal temperature differences on growth and feed utilization efficiency of poultry are well recognized* In the 1966 Turkey Research Summary, marked differences in performance attributable to type of house were reported (6), In the cool, breezy pole barn, toms weighed 1*25 lb* more at 25 weeks of age than those in the fanventilated and warmer brooder house. However, birds in the pole barn required more than a pound more feed for the pound of body weight gained during that week* The trend to growing turkeys the year-round in widely varying types of housing clearly points to the need for studies on temperature programmed feeding of turkeys. In broilers, continuous light has been shown to give superior performance when compared to light and dark periods* When birds reared under high light intensity (0*75 to 10 foot candles) are compared to those raised under low intensity (.05 to.12 foot candles), the best growth rates were obtained when either high or low intensity was given continuously* No difference was noted between high and low intensity for feed efficiency (l). In another recent report concerning broilers, either 12 or 2i hours of light at 0.5 foot candles was better than less light at the same intensity (Ij.)* In a previous study, Skoglund and Palmer found 0.5 foot candles to be the best for promoting growth (5)* Foss et al* studied the effect of wave length of light on growth rate and found light of either blue or green color to be associated with a more rapid growth rate than red light (2)* However, the red light was more effective in inducing testes weight increases* No data of this type exist for turkeys* Efficient and economical growth of turkeys utilizing nutrients not needed by the human population will continue to be a goal of researchers concerned with poultry production* However, much more information is needed at the present time on what processes are involved in growth and the nature of the control of these processes* These are extremely complex questions* However, there is some information available in the literature concerning hormonal and environmental effects on growth* The anterior pituitary is a key gland in this respect* It produces hormones which control other endocrine glands, such as the gonads, the thyroids, and the adrenals, as well as a growth hormone and a prolactin hormone* This report deals with growth hormone* When growth hormone is injected into young animals in which the pituitary gland has been removed, growth is resumed* At this time, the animals go into a positive nitrogen balance, the level of amino nitrogen in the blood plasma falls, their long bones begin to grow again, and the level of free fatty acids in the blood plasma and the liver lipids increases* When long bones grow, calcification takes place at the growth sites* At such sites, lipid is accumulated, indicating i -36-

40 a need for lipid deposition to obtain long bone growth* Adult rats accumulate protein and grow only as long as their adipose tissue lipid stores persist* Thus, growth hormone enhances fatty acid mobilization and metabolism, and lipids are necessary for growth to occur. Several workers have reported that the substitution of fat calories for carbohydrate calories resulted in improved weight gains and greater protein and energy utilization of chicks (3) and turkeys (7, 8 5 9). Experiment 1 Keithley-McPherin large white poults were brooded conventionally to 8 weeks of age, which was July 12 for the toms and August 3 for the hens* They were then randomized into eight pens in the pole barn to provide duplicate pens of each of the following bird densities: toms, I}, and 7 square feet per bird; hens, 2 and 3 square feet per bird* The birds were fed on the regular six-ration feeding schedules for toms and hens as reported in the 1966 Turkey Research Summary (6). The average body weights and feed conversions for the various intervals (as well as the cumulative feed conversions for the entire period) are reported in Table 1. As expected, the best growth occurred in the less crowded groups of both sexes. Suprisingly, though, the best overall feed conversion occurred in the more crowded groups. The reason for this can be seen in the data presented by intervals. Through 19 weeks of age in the hens and 20 weeks of age in the toms, the differences between bird density treatments were either very small or tended to favor the less crowded groups. From this point, however, the feed conversions were obviously superior for the more crowded groups~-the toms at i square feet and the hens at 2 square feet per bird. This response tended to coincide with the onset of cold fall weather and indicates the value of body heat derived from pen mates. Another factor which would contribute to increased efficiency of feed utilization was the saving in energy resulting from the obviously reduced activity of the crowded birds. The incidence of mortality and culls is presented in Table 2. For the toms, there were no culls and mortality of about 2 percent was very low and not affected by treatments. For the hens, mortality of 3,8 percent for the crowded group was not much greater than the 3*5 percent of the less crowded groups. However, the 0.6 percent incidence of cull birds in the crowded group as compared with only 1.2 percent in the other group at 21 weeks of age indicated that 2 square feet per bird was inadequate. Experiment 2 Nicholas large white torn poults hatched November 11 were reared conventionally to 8 weeks of age except that, after 5 weeks of age, the temperature in the brooder house was gradually reduced to about lj.0 0 F. by the time the birds were 8 weeks of age on January 6. Light intensity was also reduced somewhat during this period. At this time, they were distributed at random into six pens in the pole barn and six pens in the brooder house at a density of approximately Ij. square feet per bird. The pole barn was of such open construction that temperatures inside were similar to-those outside. The brooder house, on the other -37-

41 Table 1. -Effects of Seasonal Temperatures and Floor Space on Growth and Efficiency of Large White Turkeys in Experiment 1* Date TOMS A«ra If Sq. Ft. Wks. Wt. F/G 7 Sq Wt.. Ft. F/G Age Wks. HENS 2 Sq. Ft. Wt. F/G 3 sq Wt. ^Ft. F/G 7/5 8/2 8/30 9/27 10/11 10/18 10/25 11/ if 25 if.97 9.if6 34.if8 18.9if if if if. 91 if Cumulative if if Feed Conversion Table 2. Effects of Floor Space on Incidence of Mortality and Culls in Large White Turkeys in Experiment 1. TOMS HENS if Sq. Ft. 7 Sq. Ft. 2 Sq. Ft. Mort. Culls Mort. Culls Mort. Culls 3 Sq Mort.. Ft. Gulls 3/93 0 0/ /195 10/184 if/130 1/126 1/92 0 2/ /197 15/193 5/130 2/125 Total Percent if/ / /392 25/ / /251 * *» '4*

42 Table 3- Schedule of Rations Fed Large White Toms in Experiment 2 Protein). Date Age Weeks Regular Schedule Advanced Schedule 11A1/ / 2/ I/ 6/ A3/ AO/6? /17/ /2U/ lit. 8 5/ 5/ lit hand, had a hot air heating system which was used in an attempt to maintain a temperature of approximately 60 F* Temperatures in the pens were recorded continuously. Except for one brief period, the weekly mean temperatures in the warm house averaged 57 F* and daily means fluctuated from 2 to 63 F«. In contrast, weekly mean temperatures in the cold house averaged 36 F. and daily means ranged from 30 to 5>0 P* from January 6 through March 3* Then they averaged 5>1 F. and daily means fluctuated from 1^7 to 57 F* until May 12, when the experiment ended. Three pens of birds in both the cold and the warm house were fed on either the regular or the advanced schedules as outlined in Table 3» The former represents the regular six-ration schedule with this exception: the 16 percent protein ration normally fed to 22 weeks of age was fed until 2 weeks of age to insure adequate protein intake during the warm spring weather encountered. In the advanced schedule, the feeding schedule was advanced one step after 9 weeks of age. Thus, lower protein-higher energy feeds were being fed at any given time than was generally the case for the regular schedule* The average values for weight gain, feed conversion, and cost of feed per pound of gain are given in Table 14.. The feed ingredient costs pertain only to this experiment but provide a necessary means of comparing the temperature programmed treatments. The data for the advanced schedule (the higher energy feeds) in the warm house are not presented. By 16 weeks of age, growth was so obviously depressed by this combination that the regular feeding schedule was resumed. -39-

43 Table U. Effect of Temperature Programmed Feeds on Weight Gain, Feed Conversion, and Feed Cost Per Pound of Gain in Large White Toms from 0 to 26 eeks of age in Experiment 2. House Feed Schedule Weight Gain Feed Conversion 1 Cost Per Lb. Gain Warm Regular 28,60 3* Cold Cold Regular Advanced U-191 U H.U8 ^-Feed ingredient cost only, based on: Corn $5l»2Q/ton Soy (lilt) $95.0Q/ton Concentrate $129.00/ton. Table 5«->«Schedule of Rations Fed Large White Toms in Ebcperiment 3 (% Protein). Date 11/17/67 12/ 8/67 1/12/68 1/26/ /68 2/23/68 3/8/68 3/22/68 li/$/68 It/19/68 #10/68 5A7/68 Age, Wks lit $ 26 Regular Advanced Delayed ' U 1U -lj.0-

44 The heaviest average 26-week weight, lb., was obtained in the cold house with birds fed on the regular schedule* The effect of cold temperature on feed intake is demonstrated by the very poor feed conversion of I]_*191* In the cold house, the higher energy feed schedule yielded a slightly lower average weight, indicating a lessthan-perfect balance of calories to protein for maximum gain* The feed conversion of [(..138 does not appear to be a great improvement over that of the regular schedule. The energy intake for these two groups was similar, as expected* The advanced schedule, however, allowed the birds to consume the calories they needed without the considerable over-consumption of protein and other critical nutrients as was the case with the regular schedule. The result was a dramatic saving in the cost of each pound of gain, llj-,1^8 cents compared to 15*33 cents for the regular schedule a saving of 0.85 cents per pound of gain. This represents about 25 cents per bird. On the regular feed in the warm house, the obviously lower weight, lb. at 26 weeks of age, indicates a need for further refinement of the feeding schedule for these temperatures* However, the much better feed conversion of and the lowest feed cost per pound of gain, cents, demonstrate the value of a heated building. Experiment 3 Amerine large white torn poults hatched November 17 were brooded conventionally to 8 weeks of age, January 12, except that after 5 weeks of age, temperatures were gradually reduced to i _0 F* Light intensity was also reduced somewhat during this period. The birds were then randomized into 12 pens at a density of 1 *7 square feet per bird* Prom 8 to 26 weeks of age (May 17)* the birds were maintained under semidarkness conditions with light intensity of 0*05 to 0*2 foot candles* Lights in the corridor were turned on for periods of about 1/2 hour when attendants were looking after the birds* One advantage of low intensity light in broiler production is that debeaking becomes unnecessary* To test the effectiveness of this treatment in turkeys, these birds were not debeaked* The house was divided in half by a solid partition which permitted for the first time a comparison of two different temperatures in the same building* The birds in half of the house were heated by radiant electric brooders raised to a height of Ij. feet* The birds in the other half of the house were subjected to cold conditions near ambient temperatures by thermostatic control of the exhaust fans. Temperatures in the pens were recorded continuously* It should be remembered that the birds absorbed heat directly from the radiant heat source so that they were probably comfortable even when the air temperature recorded somewhat under the desired 60 F. The weekly mean temperature differential between the warm and cold halves of the house ranged from 6 to 11 F* until April 12, when the birds were 21 weeks old* From this time on, warm outside temperatures brought mean inside temperatures to about 60 in both halves of the house, with daytime high temperatures in the 70 f s* The schedule of rations fed is shown in Table 5* The regular sixration schedule, fed to triplicate pens in each half of the house, was modified as follows: the 22$ protein ration was fed starting at 10 -in-

45 Table 6*--Effect of Temperature Programmed Feed on Weight Gain, Feed Conversion and Feed Cost per Pound of Gain on Large White Toms from 0 to 26 Weeks of Age. (Experiment 3) House Feed Schedule Regular Warm Delayed Regular Cold Advanced 0-22 Weeks Gain 2U.U8 2U.27 2k. Qk Feed/Gain U 3.57 Cost/lb Gain, cents * Weeks Gain U Feftd/Gain U Cost/lb Gain, cents Weeks Gain U Feed/Gain 3.96 U.09 U.17 U.OU CostAb Gain, cents UU 18. U9 17. U2 3-Based on feed costs quoted by OJL.R.D«C* feed mill; include charges for ingredients, mixing, pelleting and overhead. Table?. Effect of Supplemental Fat and Light Intensity on Weight Gain and Feed Conversion of Large White Toms in Experiment U- Light Intensity 3.6 Foot Candles 0*02 Foot Candles Supplemental Fat Ave Ave Wt., 16 Wk., Ib We. Wt. Gain, Ib. Feed Conversion S U lli ii83 3.1*25 3.U55 3.Ola

46 rather than 8 weeks of age; the li $ protein ration was fed starting at 25 weeks of age (the latter delayed from 22 weeks of age because of the warm spring weather encountered) * In the cold half of the house, triplicate groups were fed on this schedule except that it was advanced 2 weeks after 8 weeks of age* thus providing a higher energy feed program* In the warm half of the house, the opposite was true to accommodate the reduced need for calories, the schedule was delayed "by 2 weeks after 8 weeks of age. Table 6 shows the average weight gains, feed conversions, and feed costs per pound of gain. The feed costs were those charged by the OARDC feed mill and include charges for ingredients, mixing, pelleting, and overhead* These costs apply only to this particular set of conditions but provide an important means of comparing the treatments* The effects of cooler environmental temperatures on growth are shown by the greater gains in the cold half of the house* The poorest feed conversion was obtained in the cold house on the regular feed schedule* By advancing this schedule to provide higher energy lower protein feeds at earlier ages, it was possible to obtain equally good, if not better, rates of gain to 22 and 2l± weeks of age. Furthermore, feed conversion was also greatly improved on this advanced schedule and, since this schedule involved more of the cheaper feeds, the feed cost per pound of gain was likewise improved* These two items were in fact almost identical to those of the birds fed on the regular schedule in the warm half of the house. The fact that the birds fed the higher energy feeds in the cold house grew at least as well as those on the regular feeds shows that the latter were greatly overconsuming protein and other critical nutrients as they ate to satisfy the need for calories to maintain body temperatures* In the face of the greater weight gains in the cooler environment, the lack of response to the delayed feed schedule in the warm environment is unexplained at the present time* The lack of improvement in either growth or feed conversion, coupled with the fact that the delayed schedule involved feeding more of the higher cost feeds, resulted in an increased cost of feed per pound of gain* All of the birds in this trial were grown from 8 to 26 weeks of age under the very low light intensity of 0.05 to 0*2 foot candles* Although there was no control group for comparison of the light intensity effect, the overall performance of the flock, especially through 22 weeks of age, was very good (average gain to 22 weeks was 21^.65? lb*)«none of the birds had ever been debeaked, yet there was no evidence of fighting or injury that would contribute to down-grading of dressed birds* They were extremely well finished and their feathers were clean and smooth* Experiment![. This experiment represents a departure from temperature programming experiments* The fine performance and the excellent condition of the birds on Experiment 3 P^cropted a more detailed and controlled study

47 of the effects of low intensity light. Variable speed fans with thermostatic controls were installed* The fan ducts were enclosed and baffled against light. Variac controls permitted infinite selection of light intensity separately for each half of the house* The light half of the house was provided a level of 3*6 foot candles and the dark half of the house was provided less than 0.02 foot candles. Triplicate pens of birds in each half of the house were fed either the regular six-ration schedule or the same schedule with the rations containing a low level (2 to I), percent) of supplemental fat.l All birds were debeaked since half of them would be exposed to a normal level of light. Nicholas large white torn poults hatched June 5 were brooded conventionally and the study was initiated July 31 when they were 8 weeks old. It is scheduled to terminate December Ij. when the birds are 26 weeks old. At the time this report is being prepared, results are available to 16 weeks of age only. The average weights and feed conversions are shown in Table 7* The low intensity light treatment started at 8 weeks of age resulted in a 1/2-pound heavier bird by 16 weeks of age. Peed conversion for the interval of 12 to 16 weeks of age was improved by 8 percent. The effect of 2 to Ij. percent of supplemental dietary fat was apparent only in the low light group. Here it yielded an 8.6 percent improvement in the efficiency of feed utilization, with most of this improvement attributable to the added fat diet, which was 12.0 percent better than the fat supplemented group under normal light. Thus, the combination of low intensity lighting and added dietary fat in diets with similar calorie-protein ratios gave superior performance in this trial up to 16 weeks of age. The basis for this improved efficiency is not readily apparent. During the early growing period, it might be explained by some type of relationship between growth hormone and fatty acids. During the late growing period, when less protein and more fat is deposited, the beneficial effect could be explained by direct deposition of fat rather than forcing conversion of carbohydrate calories to fat calories which are then stored. Understanding the nature of the extracaloric benefit of added dietary fat may give insight into future efficiencies concerning turkey meat production. References 1. Beane, W«L., P. B. Siegel, and H. S. Siegel Light environment as a factor in growth and feed efficiency of meattype chickens. Poultry Sci. I)V Foss, D* C., G. A. Donovan, and E. L. Arnold. 196?. The influence of narrow bands of light energy on growth, testis weight, pituitary weight, and gonadotropin production of male chicks. Abstract, Poultry Sci. i+6: * ' Procter and Gamble Company r s hydrolyzed animal and vegetable fat, HEP.

48 3. Rand, N* T.. H. M* Scott, and P. A* Kummerow* 1958* Dietary fat in the nutrition of the growing chick* Poultry Sci* 37* Ij.. Skoglund, * C*. C* J* Wabeck, and D* H. Palmer* of light period for maximum broiler weight* 1966* Length Poultry Sci* 1+5: Skoglund, * C. and D. H. Palmer* 1962* Light intensity studies with broilers. Poultry Sci* 1+1: * 6* Touchburn, S* P. and V* D* Chamberlin. 1966* Feeding schedules for growing turkeys* OAKDC, Turkey Research-~1966, Res. Summary 17, pp* 34-^1 * 7* Touchburn, S. P* and E. C* Naber* 1966* The energy value of fats for growing turkeys* Proc*. Thirteenth World! s Poultry Congress, Kiev, U*S*S*R*, pp * 8* Waibel, P* E. 1958* Effectiveness of unknown growth factors, antibiotic and animal fat in turkey poult rations* Poultry Sci* 37: 9. Yacowitz, H., R* D. Carter, J. Wyne, and M* Q-* McCartney. 1956* Effects of varying protein and fat levels in a finishing ration for turkey broilers* Poultry Sci* 35: Acknowledgments The authors express appreciation to Cuddy Farms, Division of Cuddy Foods, Ltd*, Strathroy, Ontario, Canada, for donation of the Nicholas poults used in two of the experiments; Amerine Turkey Breeding Farms 5 Oakdale, California, for the Amerine poults used in one experiment; and the Procter and Gamble Company, Cincinnati, Ohio, for the HEP used in the fourth experiment*

49 FEEDING THE BREEDER TURKEY I. OUT-OP-SEASON HATCHING EGG PRODUCTION S. P«Touchburn Department of Poultry Science The trend in the turkey industry is to year-round production* The industry can not much longer tolerate the luxury of using its facilities and human resources only part of the year. One of the most serious limitations in this industrialization, however, is the scarcity of large tjpe poults during a considerable part of the year. The following study was initiated to test the feasibility of year-round production of large type poults* Eggs of the Keithley-McPherrin female line were obtained from the K-M Turkey Breeding Farm, Sonoma, California. Schedules were arranged for the following hatch dates: Flock 1, January 2?; Flock 2, April 27; Flock 3, July 13* Eggs for Flock Ij., scheduled to hatch October 19j were obtained during the first 2 weeks of production from Flock 1. The birds were reared in confinement and fed the regular series of six growing rations, with the sixth (lij. percent protein) ration being fed from lo to 28 weeks of age. Light was restricted to a 6-hour day from 21 to 28 weeks of age* At 28 weeks of age/the day length was increased to ll hours and the experimental breeder diets were fed. The first LJ.~week reproductive period started when the hens were 32 weeks of age and had achieved approximately 50 percent production* The test was to be terminated after 21}, weeks of production when they were $6 weeks old* From 21 weeks of age, the birds were housed in windowless^ fan ventilated houses with supplemental heat* With this system an attempt was made to maintain minimal daytime temperatures of 5>2 F* and nighttime temperatures of I _2 0 F* as long as outside temperature permitted* Table 1. Energy and Protein Contents of the Regular and Reduced Energy Turkey Breeder Rations. 1 2 Regular Reduced Energy Protein, % Calories/lb,, Productive Calories/lb., Metabolizable P.E./P, 52.6 Ii5.il M.E./P *.U -46-

50 Duplicate pens of 16 hens each were fed either the regular turkey breeder diet or a reduced energy diet* The protein, energy, and calorie-protein ratios of these diets are outlined in Table 1. Hens were inseminated weekly with pooled semen from toms fed the regular torn breeder diet. Eggs produced were handled according to the standard management procedures in practice at the Research Center and reported elsewhere in this publication* They were set weekly and those removed on candling after 7 days of incubation were examined macroscopically to differentiate infertility from early embryonic mortality* Egg weights were determined by weighing all eggs set during 1 week out of every 1+. Results The performances for the reproductive periods of Flocks 1, 2 5 and 1+ are shown in Table 2. Flock 1 was kept the full 2)4. weeks on test and maintained an excellent average egg production of 51+ percent Table 2.--Season and Diet Effects on Reproduction and Body Weight Changes of K~M Female Line Turkey Hens. Flock 1 2 ij_ Date Eggs Set 9/3-4/67-2/15/68 12/7/67-3/7/68 5/31/68-8/15/68 No. of Weeks 2Jj. llj. 12 Breeder Diet Eggs Set/Hen/Day ^5 0* *572* ^1+8 S.E* 0, ? % Fertile 78* * *82 s.e. 3*51 2*^5 1^*30 fo Hatchability L&* S.E« Av. EggWt., Gm lf* *1+1 80* S.E ^ Av. Body Wt. Change, Gm Av* No. of Poults * * *52 Weekly Mean Temperature: High Low 56*9 1+3* ^"Significant

51 during this period* Fertility and hatchability were also high, averaging 78 and 67 percent respectively* Except for a small loss in weight during the first month of lay, "body weight increased slightly throughout the period. The average net increase was 3^1-9 grams for the controls and 206 grams for the birds fed the lower energy diet. The only other difference was a significantly greater average egg weight for the birds fed the lower energy diet. The reproductive test for Flock 2 was terminated after li weeks of age because of a serious infection of staphylococcus* The infection was traced to foot injuries sustained when the hens were placed in broody pens in which barbs on the wire mesh floors apparently pierced the foot pads* The infections localized in the feet and hock joints, causing fever, lameness, and cessation of egg production. The significant improvement in reproductive performance of the lower energy fed birds in Flock 2 may be a real response to the greater concentration and consequently greater intake of the non-energy nutrients* It is entirely possible, however, that the differences simply reflect chance differences in the degree of severity of the staphylococcus infection* The latter is the more likely possibility in view of the fact that with Flock 1 the higher energy level of the control diet did not hinder performance during a time when pen temperatures averaged slightly warmer than in this second test* If the infection had not occurred, it was anticipated that Flock 2 would have successfully completed 2i(. weeks of production in mid-may. Pen temperatures for both Flock 1 and Flock 2 were moderate and would likely have remained so at least most of'the time until mid-may* Flock 3 developed paracolon infection which prompted its liquidation at ll weeks of age. Flock 1+, which started laying May 2lj., was subjected to high temperatures throughout the 12 weeks of its performance test. The weekly mean high and low temperatures in the pens averaged 78*9 and 61j.*ij. 0 F* respectively* The experiment was terminated after 12 weeks of production because most of the birds had ceased laying eggs, The complete lack of any beneficial effect of a reduced energy diet during this test indicates that the poorer reproductive performance in hot weather cannot be attributed simply to an excess of calories in the diet which restricted the intake of critical nutrients* This would leave two alternatives* First, it is possible that the balance of essential nutrients required is different during hot weather than during more moderate weather* Certain vitamins, essential amino acids, or minerals may be required in greater or lesser amounts because of altered metabolic needs* Second, the poorer performance may be a physiological phenomenon which will not respond to nutritional manipulation. Further research is needed to resolve this problem* This study with limited numbers of birds has not yielded conclusive evidence but it tends to indicate that the levels of nutrients in the 17»3 percent protein control diet are adequate*

52 Wahid et al.i/ fed large type turkeys breeder diets with protein levels of 19* 21, 235 and 25 percent, with energy decreasing as protein increased* They found that feeding the higher protein diets yielded three to six more eggs per hen and a slightly larger egg than the 19 percent protein diet. Feeding the 21 percent protein diet resulted in slightly more poults per hen. This experiment, however, was conducted from August 1 to December 1? in Texas. It therefore represents extremely high temperatures and the results probably would not apply to Ohio conditions. /Wahid, M. A.,. P. Kruger, C. B. Ryan, and R. L. Atkinson Optimum Protein Levels for Off-Season Turkey Hatching Egg Production* Abstract, Poultry Sci. lj.6:

53 FEEDING THE BREEDER TURKEY II. UNIDENTIFIED REPRODUCTIVE AND PROGENY GROWTH FACTORS S. P. Touchburn, E. C. Naber, and R. D. M. Silva Department of Poultry Science In an attempt to speed up the progress of research on unidentified dietary factors, the Japanese quail, Coturnix coturnix japonica, has been introduced as a pilot animal. In 196? and 1966," the experimental turkey breeder diets were fed simultaneously to the breeder turkeys and breeder quail. Portions of each batch of feed fed to the turkeys were fed to the quail so that differences in response could not be attributed to differences in mixing or feed ingredients. The diets fed in 196? were the simplified corn-soybean meal basal, the corn-soy basal supplemented with 2 percent dried fish solubles, and a complete practical diet. In 1968 the diets fed were the corn-soy basal, the corn-soy basal supplemented with 2 percent dried fish solubles, and a purified cornstarch-isolated soybean protein basal diet. Results The reproductive performances of the turkeys and Japanese quail are compared in Table 1. The complete breeder diet fed the turkeys in 1967 resulted in significant improvements in egg production, fertility, and hatchability over the corn-soy basal diet. Supplementation of the corn-soy basal diet with 2 percent dried fish solubles partially improved fertility but it appeared to cause a depression in hatchability. This latter effect is unexplained. When fed to the quail, the experimental turkey breeder diets had no effect on egg production or fertility. Hatchability was not affected by the diets during the first part of the season* During the second part of the season, however, hatchability was significantly improved in the quail - fed the complete breeder diet, A partial response was obtained in the group fed the corn-soy with dried fish solubles added. Thus, depletion of body stores of unidentified factors appeared to have played an important part in the response of the quail* The greatest response to unidentified factors in turkeys would also be expected late in the reproductive period after depletion. However, the poor egg production and the variation in production among individual turkey hens in the latter part of the reproductive period increases the variance and reduces the possibility of obtaining statistically significant differences in hatchability. In 1968 the turkeys showed no differences in fertility or hatchability on the experimental diets. Egg production was poorest on the corn-soy basal diet and was improved by addition of dried fish solubles. An unexpected result was the relatively high level of production, fertility, and hatchability on the purified (starch-isolated soybean protein) basal diet. As anticipated, however, the quail consuming the purified basal diet showed significantly depressed egg production, fertility, and hatchability. The lack of response in hatchability to supplementation of the corn-soy basal diet with dried fish solubles is similar to that of the turkeys. -50-

54 Table 1*--Comparative Reproductive Performance of Turkeys and Japanese Quail Fed Experimental Turkey Breeder Diets* No. Eggs Set Turkeys Quail No / Total Hen /Day No. Pertility Turkeys Quail Hatchability Turkeys Quail 1967 Corn-Soy & b CS + Fish Sols, a b Complete a b Significance a b 1968 Purified Corn-Soy CS + Pish Sols. Significance 0.1^ o. 1^ ^ N.S. N.S ; N.S N.S. N.S lj.1 1 1* C--X- -x-x- -X- -X- -X--X- -X--X- -X- -X--X- -x-x- 53. k N.S N.S. X- -X- ~ first part of season; b - last part of season. Table 2'--Effect of Parent Diet and Poult Diet on Average Weight of Poults at h Weeks of Age. Poult Diet 1 (CS) (gno Parent Diet 2 (CS+F) (gin) 3 (P) (gn) 1. Corn-Soy Basal U U6l 2. GS + 2% Dried Fish Solubles U8l 3. u. Purified Basal P. + 2% Dried Fish h8l Solubles U65 U7U U65 U18 kh3 L.S.D. P<05 U7 P<.01 62

55 The effect of parent diet and poult diet on average [(.-week weights of poults is presented in Table 2. The heaviest poults were those which received fish solubles either as a supplement to the corn-soy diet (530 and 2 grams) or through the egg from the diet of the dam (529 grams). The response to fish solubles in the corn-soy basal poult diet was apparent when hens were fed either the corn-soy or the purified basal diets but not when hens were fed the fish solubles supplemented diet* The lightest poult weights were obtained when both parent and poult were fed the purified basal diet (lp.8 grams). The lack of response to fish solubles supplementation in the purified poult diet may indicate an interdependence of unidentified factors from fish solubles and soybean meal. On the other hand, if the soybean meal factor and the fish factor are identical, then it would mean that the 2 percent level of fish solubles supplementation did not provide enough of the factor to yield a maximum response* This view is supported by the data for average weight of quail chicks fed six levels of dried fish solubles (Table 3)* The graded response to increasing levels of fish solubles indicates that the 2 percent level generally fed could very well be inadequate. This would account for the lack of response to fish solubles in hatchability. Chu and Potter / fed graded levels of fish solubles to turkey poults. Average 8-week weights increased with increasing levels of Table 3.--Effect of Graded Levels of Dried Fish Solubles on 2 Week Weights of Quail from Parents Fed the Corn-Soy Basal Breeder Diet. Level of Dried Fish Solubles in Chick Diet Ji.O 8.0 Av. Weight of Quail Chicks at 2 Weeks (Grams) * 31-8*.-JHf 33-5 Cornstarch-isolated soybean protein basal diet5 two basal mixtures, one containing no dried fish solubles,, the other containing 8$ of dried fish solubles were mixed in various proportions to give the graded levels* I/Ohu, A. B* and L. M. Potter. 196?. The Evaluation of Fish Solubles in Diets of Young Turkeys. Abstract, Poultry Sci. J+6:

56 fish solubles to 3 percent of the diet. It is important to note that levels of 0, 2, 1^., and 6 percent of supplemental fish meal had no significant effect on growth* This emphasizes that the activity resides in the water soluble portion of the fish and that fishmeal is not necessarily a reliable source of the fish factor. These turkey-quail experiments demonstrate the usefulness of the Japanese quail as a pilot animal for research on unidentified dietary factors. Their small size and consequently limited feed requirements especially favor their use in future studies involving fractionation of the dried fish solubles when limited quantities of the prepared material will be available. -53-

57 FEEDING THE BREEDER TURKEY III. A REVIEW OF THE RECENT LITERATURE S. P. Touch/burn Department of Poultry Science Earlier research in the feeding of breeder turkeys was reviewed 2 years ago (12). This article will summarize advances reported in 196? and Atkinson et al. (2) found that, with large bronze turkeys in floor pens, 1*67^ dietary calcium gave good production and hatchability while 3 19$ calcium gave maximum production but slightly depressed hatchability. Inorganic phosphorus levels in the diets were 0.61 _ or 0.78 percent* Arends et al. (1) obtained highest hatchability at 2.2.$% calcium. Hatchability was depressed at 0.75 or 3«0/ calcium. Skeletal mineralization was greatest with diets containing 2.25$ calcium and 0.8% phosphorus. The National Research Council (10) recommends 2*25% calcium and 0.75$ phosphorus. These values appear to be optimal and should not be altered based on data available to date. Atkinson et al. (2) reported that, when housed in laying cages, large bronze required 1.90^calcium to prevent embryonic mortality while large white turkeys required 2.66^. Results with large white breeder turkeys.in laying cages at OARDG tend to confirm this greater need for calcium. Diets containing 2.25$ calcium and 0.75% phosphorus led to a decline in shell quality which was at least partially alleviated by feeding supplemental oyster shell. However, a word of caution is in order. Free choice feeding of oyster shell or grit should be avoided because flocks or at least individual birds may overconsume these materials under certain conditions. Experience here has shown that caged birds may eat excess oyster shell even when feed is available. Cooper and Barnett (ij.) reported that oyster shell and grit consumption by turkeys increased when mash consumption was restricted to 80$of ad libitum consumption. Another mineral element deserving reassessment is manganese. Atkinson et al. (3) reported that, based on reproductive performance, the optimum level of dietary manganese was between 5^1 and 108 ppm. This is much higher than the 33 ppm. (33 mg./kg. or 72.6 mg./lb.) requirement level listed by NRC (10). Jensen (8) reported the first evidence that the mineral element selenium could replace vitamin E for maintaining normal hatchability. Although this work was done with Japanese quail, it is likely that similar effects will be observable with chickens and turkeys. Scott et al. (11) fed turkey poults diets containing corn and soybean meal from areas where the soil content of selenium is low (Ohio is such an area). They found the dietary selenium requirement to be 0.18 ppm. in the presence of vitamin E and 0.28 ppm. in the absence of vitamin E. Supplementation with the sulfur amino acids, methionine and cystine, was ineffective in preventing the myopathies which occurred in the following order of prominence: first, smooth muscle (gizzard); second, myocardium (heart); third, skeletal (breast) muscle. Because of the very narrow tolerance between efficacy and toxicity of selenium, the -&.-

58 TJ*S. Food and Drug Administration will not allow use of selenium or selenium salts as feed additives* The best alternative is to feed about 5$ of seleniferous wheat middlings obtained from Minnesota or the Dakotas. The folacin requirement for optimum hatchability and progeny performance of turkeys was reported by Miller and Balloun (9) to be 1*23 mg./kg. (2*71 mg./lb.) of diet* This represents a considerable increase over the 1966 NRG recommendation of 0.8 mg./kg. Cropper and Scott (7), using a modified AOAC-19^5 method, showed folic acid present in most feedstuffs as bound or conjugated and that this was fully utilized by chicks and poults. They cautioned against conclusions drawn from use of the I960 AOAC method since this measures only free folic acid. Using gas chromatography, Cooper and Barnett (5>) found that corn oil contained $6% linoleic acid. When %% corn oil was added isocalorically to practical breeder diets, average egg weights were increased 3 grams* This treatment caused no changes in egg production, hatchability, feed consumption, or body weight. Cooper and Barnett (6) restricted nutrient intake and mature body size of turkey toms by feeding low density diets containing coastal Bermuda grass meal starting at 2i or 35 weeks of age. In natural mating tests, fertility of males fed coastal Bermuda meal at 30 and ij.0$ levels in the rations generally improved, with the greatest improvement being obtained on the l±qfa diet. Although this response with natural mating might be attributed to increased physical activity, it is possible that it might also reflect improvements in semen production. An experiment conducted here and reported in 1966 (12) showed that, when toms were restricted to Qofo of ad libitum consumption from 12 to 2ij. weeks of age, subsequent semen production was increased* References 1. Arends, L* G*, D* L* Miller, and S* L. Balloun Calcium requirements of the turkey breeder hen. Poultry Sci. ij.6: Atkinson, R* L*, J* W* Bradley, J* R* Couch, and J. H. Quisenberry. 19&7* The calcium requirement of breeder turkeys* Poultry Sci* 1^6: 207~21i _* 3* Atkinson, R* L*, J* * Bradley, J. R. Couch, and J. H. Quisenberry Effect of various levels of manganese on the reproductive performance of turkeys* Poultry Sci. lj.6: Ij. 72-1^75 Ij.. Cooper, J. B* and B* D. Barnett Oyster shell and insoluble grit consumption of breeder turkeys* Poultry Sci. 1 6: * 5. Cooper, J* B* and B* D* Barnett. 1968* Response of turkey hens to dietary linoleic acid fed'as corn oil. Poultry Sci* *

59 6. Cooper, J. B. and B. D. Barnett. 1968* Effect of diet of turkey males on fertility. Poultry Sci. lj.7: * Cropper, W. J. and M* L. Scott Studies in folic acid nutrition in chicks and poults. Brit. J. Nutr. 8: 65>-73«8. Jensen, L* S Vitamin E and essential fatty acids in avian reproduction. Federation Proc. 27: 91^ * Miller, D. L* and S. L. Balloun Folacin requirements of turkey breeder hens. Poultry Sci. ij.6: l 02-l5o National Academy of Sciences National Research Council Publication 13^5* Nutrient requirements of poultry. 11. Scott, M. L., G-* Olson, and L. Krook. 1967* Selenium responsive myopathies of myocardium and of smooth muscle in the young poult. J. Nutr. 91: * 12. Touchburn, S* P* 1966* Feeding the breeder turkey. OARDC, Turkey Research-~1966, Res* Summary 17. pp* 6-13* -56-

60 EFFECT OF SELECTING TURKEYS FOR RESISTANCE TO COLD STRESS Karl E* Nestor, Keith I. Brown, and Nikola Bachev Department of Poultry Science Stress may be defined as any harmful condition resulting from the inability of the animal to maintain an adequate internal environment* As a result, changes occur in the blood or other body fluids* A stressor is any agent capable of producing stress* Cold, heat, and lack of water are potential stressors* It is now known that stressors result in the adrenal gland producing a larger quantity of a hormone, corticosterone* Thus, the level of this hormone in the blood is an indication of the severity of the stress condition* The blood level of corticosterone after cold stress was used as the selection criterion in the development of two lines of turkeys* The cold stress involved placing I).--week-old poults in a cold room at i 0 F* for I), hours* At the end of this period, a sample of blood was taken for corticosterone analysis* One line (high line) was selected for a high level of hormone after stress while the other line (low line) was selected for a low level of corticosterone* At the end of the i.*~hour stress period, a randombred line which was not selected was used as the control* The blood level of corticosterone after four generations of selection averaged 13«6, 10.1 _, and 9«3 ug^, respectively, in the high, randombred control, and low lines* Thus, the lines are getting well separated in their response to cold stress. Research is in progress to determine the response of these lines to other stressors such as heat, exercise, and disease* The majority of the mortality in turkeys usually occurs early in life* A summary of the mortality occurring during the first l\. weeks is presented in Table 1* This mortality is divided into that occurring naturally and that occurring during the stressing procedure* A few poults die while in the cold room but most mortality due to stressing occurs while collecting blood or immediately thereafter* The low line has had consistently lower natural mortality than the randombred control or the high line. This indicates that this strain is able to withstand more adverse conditions than the other two strains* In 1966 when a serious PPLO infection (H strain) occurred, the high line had higher natural mortality than the randombred control* This was not evident in 1967 and 1960, which suggests that the high line is more susceptible to adverse environmental conditions* The reproductive data of the three lines are presented in Table 2* The low line appears to be increasing in egg production relative to the other two lines* The differences were significant in 1968* Percent fertility of the high line was significantly depressed in 196?* However, no line differences were evident in 1968, so this difference may have resulted from chance. No line differences are apparent in hatchability of fertile eggs*

61 Table 1* Summary of Mortality for the First Pour Weeks of Age. Line Year 196? 1968 Natural Mortality R. B. C. ; Low Line High Line R* B. C. Low Line High Line Mortality Due to Stress ll.l All Mortality R. B* C. I Low Line High Line ^ '"Randombred control strain 3 2 H strain of PPLO diagnosed. The growth performance of the selected lines is given in Table 3. Body weight of the low line was increased while that of the high line was decreased at ij. weeks of age. There were no significant line differences observed at 16 or 2l\. weeks of age. Summary Selection for high and low blood levels of corticosterone after cold stress was successful in establishing lines exhibiting these traits* The line showing a low level of corticosterone after stress also exhibits higher egg production, faster growth to 1 weeks of age 5 and lower mortality during the early growth period than the randombred control from which it was developed. The line which produces a high level of corticosterone after stress has similar reproduction abilities and has similar liveability as the randombred control population but has reduced body weight at l\. weeks of age.

62 Table 2*--Reproductive Performance of Selected Lines (12 wks. production)» Line % Egg Production 0 Fert. % Hatch of Fertile Eggs R. B. C. 32 High Line Low Line R. B. C. 3 High Line Low Line R. B. C. 3 High Line Low Line ^ i R. B. C. 3 High Line Low Line R. B. C. 3 High Line Low Line 50.] I7.5 1 il ll Note: Only trap nested eggs were recorded. Approximately *$% of all eggs were floor eggs* ^Differences between lines were statistically significant (P^ 2Randombred control strain 3* Table 3. Growth Performance of Selected Lines After Pour Generations of Selection* Line k wk. (gm. ) M F 16 wk. M (lb.) F 21+ wk. M (lb.) F R. B. C. 3 Low Line High Line ij-71 Ld+2 lj Difference in body weight between lines was highly significant

63 RECENT FINDINGS IN MYGOPLASMA MELEAGRIDIS RESEARCH Y* S* Mohamed and E. H* Bohl Departments of Veterinary Science and Poultry Science Reports of the U.S. Department of Agriculture indicate that airsacculitis is still the major cause of turkey condemnations at packing plants. Two members of the PPLO family of organisms are capable of producing airsacculitis in turkeys: Mycoplasma gallisepticum (popularly known as the S6) and M» meleagridis, which is often referred to as the f! H!T serotype or t! N?! strain. M* gallisepticum is the organism which causes infectious sinusitis and airsacculitis in turkeys and chronic respiratory disease in chickens. M. gallisepticum has been brought under control in the last few years after the development of reliable testing procedures and control programs* M. meleagridis is the focus of attention now as a causative agent of airsacculitis because of its widespread existence in turkey flocks* Research has been underway in the last few years at the OARDC to study different aspects of this infection in turkeys. The following is a summary of the research findings in Ohio and a review of some other findings* Significance of the Infection M* meleagridis is prevalent in Ohio turkey flocks. Reports indicate that the infection is equally prevalent in turkey flocks in other parts of the country and in Canada. Airsacculitis due to M* meleagridis has been detected in unhatched embryos, day-old poults, and 16-week-old turkeys. Indications are that the lesions heal after this age. This means that air sac lesions may be still present in fryer-roaster turkeys at the time of processing, which can lead to condemnations* Studies at Minnesota (l) indicated that turkeys hatched from tylosin-dipped eggs (to control M. meleagridis) showed fewer condemnations due to airsacculitis and/or septicemia-toxemia, as compared to turkeys originating from undipped eggs* Ohio studies indicate that M. meleagridis by itself is capable of producing airsacculitis* Lesions are usually limited to the air sacs. Bscherichia coli can complicate the condition, resulting in a disease which involves the lungs* In this case, lung abscesses are observed and the disease might be fatal* Experimental infection of germfree turkey poults with M* meleagridis, E* coli, and a combination of both organisms substantiates this observation* It is interesting to note that in these experiments E. coli infection alone did not result in any lesions* Studies at California (2) indicated that M. meleagridis infection had no deleterious effects on egg production, fertility, or early incubation mortality. However, there was a significant difference in poult yield between eggs hatched from infected hens and those from clean hens due to late incubation mortality. -60-

64 There have been field observations and suggestions attributing a direct or indirect relation of M* meleagridis infection to several other problems including twisted and bowed legs, rough feathering, stunting early in life, reduced weight gain, adult eye infections, and skeletal lameness in adult turkeys* These observations and suggestions must be further substantiated by more data to prove a relationship. Epidemiology Experiments conducted at OAKDG indicate that the organism can be recovered from the reproductive tracts of virgin male and female turkeys, The semen acts as a vehicle to carry the organism from infected males to non-infected females. It is obvious that this venereal mode of transmission makes it possible that a few infected males can insure the infection of a large population of females» The organism in the female oviduct is transmitted to the egg and the embryo in turn becomes infected (Pig. 1). Lateral respiratory transmission also occurs but in this case the organism tends to localize in the upper respiratory tract. Diagnosis Serum plate and tube agglutination tests have been developed at OARDC. These tests are satisfactory for the diagnosis of the infection. Media for isolation and methods for identification of the organism have also been developed. Control 1. The use of cultural and serological procedures to establish Mycoplasma«*free breeder flocks* This procedure would require testing sera from all the birds in a breeder flock and culturing materials collected from the tracheas and reproductive tracts of male and female turkeys* Only serologically and culturally negative birds can be used then for breeding purposeso This procedure has been used successfully at OARDC to establish a flock of turkeys free of M* meleagridis. 2. Dipping turkey eggs in a solution of the antibiotic tylosin tartrate. utilizing the temperature differential method, proved valuable in reducing the incidence of airsacculitis and Mycoplasma isolations in day-old poults* At present, most turkey flocks have a high incidence of infection with M* meleagridis* Thus, reducing the incidence by egg dipping facilitates the selection of serologically negative birds for breeding purposes. Results obtained at OARDC indicate that this procedure might afford a practical approach for the control of M* meleagridis infection in commercial turkey flocks» The procedure of egg dipping utilizing pressure differential is being compared and evaluated at OARDC with the heat differential method for possible future use* Specific Pathogen Free (SPP) Flock Considerable research has been conducted to establish and maintain a SPF turkey flock* Cultural and serological procedures were employed

65

66 THE EFFECTS OF ANTIBIOTIC COMBINATIONS ON THE GROWTH, FEED CONVERSION, AND MORTALITY OF TURKEYS 3* P* Touchburn, K* E* Nestor, and Y* S* Mohamed Department of Poultry Science Mycoplasma meleagridis is an important cause of airsacculitis in turkeys* Figures released by the U*S* Department of Agriculture indicate that in 1966 about 37*1 percent of the condemnations in turkeys at federally inspected packing plants were due to airsacculitis The purpose of this experiment was to determine the effects of two antibiotic combinations on infection by M* meleagridis and on growth, feed conversion, and mortality* Naturally infected poults were used. By examination at 1 day old, it was established that 7*2 percent of the poults had air sac lesions and 10*1 percent were infected with M* meleagridis * Three types of turkeys were represented* They were large type white, medium type white, and crosses between the two* The responses to dietary treatment were similar in all three types* In other words, there were no significant treatment X type interactions* For this reason, this report will refer only to the averages of the combined types* Three dietary treatments were compared* The control treatment was the regular six-ration schedule in use at OARDC* It is outlined in the 1966 Turkey Research Summary (Turkey Research 1966, OARDC, Res* Summary 17. p* 39) and includes different schedules for toms and hens* The second treatment group received the same feeds but were given Magnamycin-Terramycin in the drinking water from 1 day old to 5 days of age* A booster dose was given for 3 days at 12 weeks of age* The concentration was 1 gram of Magnamycin and 1 gram of Terramycin per gallon of water* The third treatment received feed containing 200 grams of Neomycin and 200 grams of Terramyoin per ton for the first pound of feed consumed per bird* At 12 weeks of age, the toms received an additional 2 Ib* and the hens an additional 1.5 l"b* of the antibiotic-^supplemented feed per bird* At all other times these birds were fed the same as the control birds* There were llj.0 male and ll^ female poults started on each treatment* Twenty-eight male poults were removed for serological tests at 2 weeks of age* The average floor space allocated was lj.*3 square feet per torn and 3*3 square feet per hen* Results For treatments 1, 2, and 3* airsacculitis lesions were observed in 11*1* 25*0, and 21*5 percent of the birds examined at 2 weeks of age* Positive isolations of M* meleagridis were obtained only in the birds showing air sac lesions* In this ^experiment, neither the Magnamycin-Terramycin nor the Neomycin-Terramycin combination was effective in eliminating M* meleagridia infection* Both antibiotic combinations significantly improved body weights at Ij. and 8 weeks of age (Table 1). However, this early advantage in -63-

67 Table 1. Effects of Antibiotic Combinations on Average Body Weight (lb.). Treatment k. Control Mag*~Terra* Neo*~Terra. Toms Hens Ij i. i _ 8 16 wk* wk* wk* wk. wk* wk* wk* *2 2lj.* lj *1+8 5*7 15* i+* *5 i5*i *28 lj_* k wk Statistical Significance" N*S* N*S. 3HC- N.S* N.S*, and N,S* = Non-Significant* growth rate was lost by 16 weeks of age so that no improvement in body weight was evident at market age* No significant treatment effects were observed in shank length, keel length* body depth, or breast width at 2i. weeks of age* The feed conversion data are summarized in Table 2* There was a tendency to improved feed conversion in the antibiotic treatment groups through 16 weeks of age* However, the improvement was significant only for the first Ij. weeks of growth* The poorer feed conversion of the toms for the first l± weeks of age (Table 2) can be explained by the fact that a sample of toras was removed for serological tests at 2 weeks of age* This can also explain the significant treatment X sex interaction for this age* Both antibiotic combinations reduced mortality but the differences reached a significant level only for the period from hatching through 16 weeks of age (Table 3)* Mortality was significantly higher for toms than for hens* Greater losses were experienced in hatch 2 than in hatch 1* Most of these losses occurred before ij. weeks of age* At least part of the mortality differences can be explained by the occurrence of a paracolon infection in hatch 2 which seemingly affected the toms to a greater extent than the hens* In the toms of the second hatch, in which the highest level of mortality was observed, the antibiotic combinations had their greatest effect* The average mortality values for the control, Mag-*Terra, and Neo-Terra groups were 27*8, li.*8, and 5*6 percent, respectively* Summary The administration of Magnamycin-Terramycin to growing turkeys had p.o effect on the occurrence of airsacculitis lesions or the incidence of infection with M* melaagridis*

68 Both antibiotic combinations were effective in reducing mortality caused by a naturally occurring infection of paracolon* Early growth rate and feed conversion were equally improved by both antibiotic combinations. Table 2. Effect of Antibiotic Combinations on Average Feed Conversion (feed per gain). 0-U H-8 Age (ides.) 8-16 l6-2ii 0-2U Treatment 1 1. Control 1.8U U Mag. -Terra U Neo. -Terra UO Sex Toms U Hens U.06 Hatch U Statistical Significance Treatment ** N.S. N.S. N.S. N.S. Sex ** N.S. JHf >#* Hatch #* N.S. -5HJ- N.S. N.S. Treatment x Sex JOC. M C< 'TW IN. D. N.S. N.S. N.S. Weighted average for sexes combined. 2 * P<.05, ** - P<.01, and N.S. - Non Significant. -65-

69 Table 3 --Effect of Antibiotic Combinations on Mortality o-u Age (uks.) ; Treatment 1 1. Control 2. Mag. -Terra. 3- Neo. -Terra. 5.1; U Sex Toms 1U 6.1; Hens 2.k 2.1* 3-1; ii.o Hatch Statistical Significance Treatment Sex Hatch Treatment x Sex Treatment x Hatch N.S. N.S. ** N.S. N.S. 1.0 l.u N.S. * N.S. * * * ** ** ** N.S. * N.S. N.S. * * Tfeighted average for sexes combined * 2 # «P<»Q5, ^ tt P<C.01 f and N«S, «Non Significant. -66-

70 NEW DIMENSIONS IN ELECTRIC BROODING- James W* Mar qu and Department of Poultry Science More turkey losses occur in the early poult stage than at any other period. It is often said that proper temperature, humidity^ fresh air (i*e*, air free from ammonia, dust, high levels of COg* etc.) will help to increase livability. However, few controlled studies have been performed which define exactly the proper environmental conditions required* In fact, present day brooding methods have evolved from the use of various types of brooding equipment on a trial and error basis with little controlled work to adequately test various brooding systems and types of brooding equipment. Turkeys have conventionally been started with a hover-type brooder utilizing either electricity or gas as fuel. Currently there is little information available on the use of infra-red energy for brooding turkey poults* However, there is plenty of information concerning the types and methods for ventilating windowless and semi-environmentally controlled brooder houses for turkey poults. It seems probable that different brooding systems will require different ventilation systems. Brooders burning a combustible gas under a hover and not vented to the outside will undoubtedly require a different ventilating system than an infrared electric brooder with no hover* Little attention has been paid to the atmosphere under the hover where the poult lives. More attention needs to be directed to studying moisture, ammonia, C02 and D at the level of the poult in the brooder house* Brooding Research at OARDC The Lincoln brooder (warm air brooding) and the infra-red brooder (cool air brooding) have been compared* This was accomplished by using an old 20 x 120-foot shed-roofed house (known as House 8)* The building was rewired and all electricity used for brooding was metered. The Ohio Farm and Home Electrification Council, Inc. cooperated in this project. Four pens of 1^2 poults each were started on November 11, 19&7* Two pens used infra-red brooders and two pens used the Lincoln brooder* The infra-red unit was a l^y-inch "linear type" brooder using two metal sheath tubes. Each unit was suspended 30 inches above the floor at start of brood and raised as needed* Each unit is rated at 3300 watts* The Lincoln brooder is made in Canada and has a small electric fan which circulates air past finned liquid-filled tubes. The liquid is heated by electrical immersion-type resistance elements and the heat is transferred to the air via the fins. Operation is fully thermostat controlled* The brooder is rated at 3000 watts. At the start of the test, it was believed that House 8 had been insulated with straw and other material years ago* Evidently when the -67-

71 Table 1. Electric Brooding Research. Type Brood No. No. of Poults Brooding Period Total KWH's KWH's per Poult Lincoln 1 86U 11/17/67-1/5/68 (7 weeks) W 5-57 Infra-red Lincoln U /17/67-1/5/68 (7 weeks) 6/6/68-7/25/68 (7 weeks) 5133* U 1.76 Infra-red /6/68-7/25/68 (7 weeks) 271*6* 2.52 Controlling radiant output has been a problem on both broods. house was moved to the present location in , much of the insulattioti material was lost* As a result, it was very difficult to obtain optimum brooding temperatures. Both types of brooders performed well and required very little maintenance* The poults were always visible* The units could easily be removed or hoisted to the ceiling during the cleanout period* The poults under the infra-red heaters could easily find their own comfort zone* The Lincoln brooder heated the entire room and men working with the poults were sometimes uncomfortable due to the heat* There were no visible differences in feather development or poult activities* At the end of the second brooding period, additional meters were installed so that lights and fans could be metered separately* New variable speed fans were installed* The air inlets were connected to ducts which distribute incoming air uniformly along the length of the house* Therefore, beginning with the third brood it will be possible to measure separately the amount of electricity used for brooding, lighting, and ventilation* It is planned to again brood poults under the infra-red heaters in the east side of House 8* (House 8 is divided by an insulated feed room*) In the west side, L* P» gas brooders will be used so that the two brooding systems can be compared* Results Table 1 gives a brief summary of the equipment used and the number of ICWH's used per poult* In both broods, the amount of KWH T s per poult -68-

72 was high with the infra-red heater. working properly. This was due to the controls not In brood 3* additional data will be obtained in regard to mortality and body weight of birds* Field Trial A new brooder similar to the Lincoln type has been built in this area and on October 1 >, 1968, 5>000 chicken-broilers were placed under five brooders at a poultry farm in Holmes County* The electricity used for these brooders is being metered and temperature records are being kept..69-

73 TURKEY MANAGEMENT PROCEDURES AT OARDC Philip A* Rentier Department of Poultry Science The following management practices are followed for all poults and turkeys reared on the Research Center turkey farm* Starting Poults All houses or pens are cleaned thoroughly before each group* Houses are washed down and disinfected or fumigated. When possible, houses should remain vacant for at least 1+ weeks before starting another group* New litter is used to the starting depth of 1 inch and more is added when needed* The litter is covered with cripped kraft paper for the first 3 to days* The poults are fed on new egg flats for the first 3 to 5 days* The litter is raked or stirred at least once a week and litter is added when needed to keep litter in a dry condition. If dropping accumulate around feeders and waterers or the litter becomes wet, the droppings and wet litter are removed and replaced with fresh litter* Poults are placed on the floor or in batteries from 2 to i{. hours after removal from the hatcher. At 2 to 3 weeks of age, three-fourths of the incisive of the beak of all poults is removed with a Lyon electric debeaker to prevent cannibalism. Growing and Finishing Poults Poults and turkeys are grown in confinement when possible* method is preferred over the range method* This If poults are moved to the range, this should be done at 8 weeks of age* The flight feathers of one wing are clipped at the time of placing the poults on range* Range flocks should be visited a minimum of three times per day* The first check should be made between 7 and 8 a*m* and the last check before dark when birds go on the roost. Range equipment is moved about 100 feet two times each week* Ranges are fenced into two sections* One section is used for a month and the second section is used for the next month* The flock is then returned to the first section, etc* Ranges are baited the same evening the poults are put on the range* It doesn! t do any good to bait earlier because foxes and raccoons are not attracted to the area unless there are turkeys present When possible, a few decoy turkeys could be put out earlier and the range baited to prevent loss of more valuable turkeys* Strychnine poisoning is used for bait* The bait is made into 2 inch by 3A-inch cylinders* This done in the following manner* A l ~inch 2 x 14. hinged with another l ~inch 2 x 1 on the top with 3/V-inch holes 1 inch apart are placed together* Hard beef tallow is packed into the 3/l -inch holes until they are half full* Strychnine tablets are placed in the center of the tallow cylinders, making sure the tablets do not touch -70-

74 the outside because the bitter taste makes the animals bait-shy* More tallow is tamped into the hole until it is filled* Thus a cylindertype of bait 3A-inch in diameter and 2 inches long is formed* The bait cylinders are put into a plastic bag with other bait, fish oil is poured into the bag, and it is shaken up* The final step is to pour sugar into the bag to coat the bait* The bait is placed around the outside of the fence* "When placing the bait, a map should be made showing where the bait is placed under trees, fence posts, rocks, etc. Then remaining bait can be picked up at a later time to prevent domestic animals from getting it* Bait should be placed in such a manner as to hide it from birds* It should be placed under grass, rocks, in depressions in the terrain and near trees, etc* Strychnine poison can be obtained from the U*S. Pish and Wildlife Service, Division of Wildlife Services, New Post Office Building, Columbus, Ohio* If further information is needed on baiting, Mr* Charles McGriff, Pish and Wildlife Service, Division of Wildlife Services, can be contacted at the same address* Breeders Breeder hens are usually restricted to a 6-hour day for at least a 6-week period prior to the start of lay* The procedure used for training hens to go into trapnests at the start of lay is: 1. Hens are palpated each morning as early as possible* If a hen has a hard-shelled egg in the uterus, she is put in the nest as soon as possible* The time of lay is recorded. 2. Hens are put in the nest three times before testing to see if they will go in the nest on their own* If found that they still lay on the floor, they should be put in the nest for three additional times and then tested again. This procedure is continued until they go in the nest themselves* Floor layers can be identified by palpating all hens in the pen. Hens which go into the nest two or more consecutive times are considered trained* Procedure for Removing Broody Hens 1* Remove broody hens Monday, Wednesday, and Friday* 2* Do not start removing the broodies before 3:30 p*m. The last egg gathering should be made at 3 : 00 p*m. 3* Check the hens on the nests* If the hen has laid during the day or has a hard-shelled egg in the uterus, release her from the nest. If the hen has not laid during the day or does not have an egg, remove her and put her in the broody pen even though she may have laid for several days previously. i;. Put broody hens back in the laying pens on Monday, Wednesday, and Friday mornings. 5* Hens which have not layed for consecutive days or more are removed to the broody pen on Fridays* -71-

75 Insemination Turkey hens are inseminated when they drop the first egg* They are inseminated again 3 days after the first insemination. After this they are usually inseminated weekly* Fumigation and Storage of Eggs Eggs are gathered at least four times each day and are cleaned during gathering. Before the eggs are fumigated, they are again checked and cleaned to make sure there is no manure, shavings, or other dirt on the eggs. Eggs are fumigated at 8:00 a.m., 11:00 a.m., 2:00 p*m*, and l4.:l.5 P*m, daily. After they are fumigated, the eggs are held at room temperature until the following morning* At this time they are put into a hatcher at 100 F* for 2 hours. The eggs are removed from the hatcher and immediately dipped into a tylosin solution of 1000 parts per million for 15 minutes* Solution is kept in a cold room at i 0 F* The eggs are put into the egg cooler at 55 F. and?5 percent relative humidity* The eggs are then cased the following day. The egg room is washed and disinfected once every month. The incubator floor is washed out at least once a month and the incubator is fumigated with formaldehyde gas after the eggs are transferred on Monday morning. The hatcher is cleaned and fumigated after each hatch* Disease Prevention and Control Clean coveralls and boots are worn by the employees. Plastic boots are provided for employees and visitors entering buildings where young poults are being reared. Water cups and range waterers are cleaned daily to prevent the spread of disease* Dead turkeys are removed from the pens and taken to the freezer. The freezer is emptied once a week and these birds are taken to the Veterinary Science Department for disposal* 1. Coccidiosis; Coccidiostat (Amprolium) is fed in the feed from 1 day to 8weeks of age. 2* Blackhead: After 8 weeks of age, a blackhead preventive ration (2 - Ibs. of Hepzide (30$) per ton) is fed continuously in the complete grower or finisher rations. If the medicated feed is to be used with whole grains, the drug level in the medicated feed must be adjusted accordingly* At the first sign of outbreak (presence of sulfur-colored diarrhea, ruffled feathers, weakness, and drowsiness) all regular preventive feed should be removed and replaced with turkey blackhead treatment feed containing 14. Ib* of Eratrymix per ton for 2 weeks* Seriously infected birds should be given individual capsules containing Emtrymix* -72-

76 At the end of the 2-week period of treatment, the birds should be continued on regular blackhead preventive feed* 3* Fowl pox: All turkey breeders are vaccinated 2-l± weeks before the onset of production by the wing-web method I -. Newcastle disease : All turkey breeders are vaccinated J^.-6 weeks before the onset of production by the wing-web method, using the Roakin strain* 5>» Pullorum paratyphoid control : At the time the Newcastle vaccine is administered, blood samples are collected from all breeders, These are taken to the State Diagnostic Laboratory at Reynoldsburg, Ohio, for the rapid serum test before the onset of production. 6. PFLO (Mycoplasma gallisepticum) control: A sample of at least 10% of the breeders, 100 minimum, is tested by the method recommended by the Animal Disease and Parasite Research Division of the U»S, Dept. of Agriculture before the onset of production* 7» Faracolon control: Blood samples from all breeder hens are tested at the State Diagnostic Laboratory. All breeder hens receive 1 Ib. of nf~l80 per ton of breeder ration to the end of production. If paracolon is suspected, poults are fed 2 Ib. of nf-l80 per ton of starter ration until the age of 3 weeks. Treatments for all other diseases are determined by consultation with the Department of Veterinary Science or Dr. G. A* Marsh, Department of Poultry Science, OSU. Nutrition OARDG Turkey Growing Ration Schedule Effective May 1968* Peed No. Percent Protein Toms Age in Weeks Hens P-l P-2-68 P-3-68 P P-5-68 P-6-68 P-7-68 P

77 Breeding Stock Breeding stock reared with sexes intermingled are fed according to the torn schedule* They receive P-6-68 (\$% protein finisher) until 6 weeks before the start of egg production; that is, until 26 weeks of age unless otherwise specified* Then they are fed either P-7-68 (Hen Breeder) or P-8-68 (Tom Breeder). Rodent Control Signs of rats and mice, such as seeing them, droppings, and burrows, are reported to the Farm Manager at once* Bait stations are maintained in all buildings and fresh bait is put before the rats and mice frequently. Water founts with soluble bait in the water are placed with dry bait, preferably in a box or station where possible* At the first sign of rodents, such as in the fall months when rats migrate the most, the baiting program is stepped up* Anticoagulant poisons are used except when they are not effective. Then the Farm Manager decides what poison is best suited* The carrier for the poison should vary to make it more palatable for the rats and mice* " Buildings are kept rodent-proof by keeping doors closed, concrete floors, and immediate repair of holes in walls and foundations* Buildings should be cleaned and free of refuse and other hiding places for rodents* Work Schedule for Weekends 1* Check young poults first* 2> Check all buildings Including waterers, ventilation, temperature, feed, abnormal birds, and any other variation from normal* If there are eggs to be gathered, the first gathering should be made on the first round of checking* 3* Do routine work starting with buildings which do not have automatic waterers* I).* Check incubator temperature and humidity at least twice a day* 5* Check ranges at least twice a day, once In the morning and before leaving in the evening * 6* Eggs are gathered at least four times a day and fumigated four times* The previous day r s eggs are dipped each day* 7* Before, leaving at the end of the day, check buildings again for waterers* ventilation, temperature, and feed* 8* Check young poults last* This procedure may vary If an emergency arises*

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