Proceedings of the 5 th Biennial Spooner Dairy Sheep Day

Proceedings of the 5 th Biennial Spooner Dairy Sheep Day Saturday, August 20, 2011 Spooner Agricultural Research Station University of Wisconsin-Madison Spooner, Wisconsin

Spooner Sheep Day was held annually at the Spooner Agricultural Research Station for 50 years from 1953 through 2002. We believe that it is the longest running agricultural field day of the several organized each year on the various Agricultural Research Stations of the College of Agricultural and Life Sciences, University of Wisconsin-Madison. After the 2002 Spooner Sheep Day, the decision was made to hold the event every-other year on even-numbered years. This decision was made so that a Spooner Dairy Sheep Day could be held on odd-numbered years with a program that could be better tailored to the focused issues of the dairy sheep industry. Therefore, there is still a sheep field day at the Spooner Agricultural Research Station every year. The 2011 field day is the 5 th Biennial Spooner Dairy Sheep Day and the 59 th consecutive sheep field day held at the station, and we hope to host many more. Sincere appreciation for organization of the Spooner Dairy Sheep Day is extended to Dr. David Thomas and Yves Berger for development of the program. The staff of the Spooner Agricultural Research Station prepares the facilities and graciously serves lunch and Kathy Monson (University of Wisconsin-Madison) prints the Proceedings. Thank you for all of your contributions. Claire Mikolayunas, Editor Department of Animal Sciences University of Wisconsin-Madison 1675 Observatory Drive Madison, WI 53706 mikolayunas@wisc.edu 2011 i

TABLE OF CONTENTS PROGRAM... 1 SPOONER AGRICULTURAL RESEARCH STATION UPDATES- Phil Holman...2 PROFITABILITY OF DAIRY SHEEP OPERATIONS Larry Tranel...3 2011-2012 SHEEP MILK MARKET UPDATE Paul Haskins...8 LAMB MORTALITY AT THE SPOONER AGRICULTURAL RESEARCH STATION (UW-MADISON) BETWEEN 1989 AND 2011 Yves Berger...10 GENETICS OF LAMB SURVIVAL David Thomas...18 RAISING LAMBS FROM WEANING TO MARKET Claire Mikolayunas...29 WHY ARE LAMB PRICES SO HIGH? Dave Johnson...39 2011 PERFORMANCE OF THE SPOONER AGRICULTURAL RESEARCH STATION FLOCK Yves Berger...41 INDEX OF ARTICLES FROM SPOONER SHEEP DAY AND SPOONER DAIRY SHEEP DAY PROCEEDINGS FROM 2000-2010...45 ii

PROGRAM 5 th BIENNIAL SPOONER DAIRY SHEEP DAY Spooner Agricultural Research Station of the University of Wisconsin-Madison Spooner, Wisconsin Saturday, August 20, 2011 8:30 a.m. Registration - Station Headquarters 9:00 Welcome and Station Updates Phil Holman Superintendent, Spooner Agricultural Research Station, CALS, UW-Madison 9:15 Profitability of Dairy Sheep Operations Larry Tranel Iowa State Extension Dairy Specialist 10:00 2011-2011 Sheep Milk Market Update Paul Haskins Sale and Marketing Manager, Wisconsin Sheep Dairy Cooperative 10:30 Break 10:45 Lamb Survival at Spooner Station Yves Berger Researcher, Spooner Agricultural Research Station, CALS, UW-Madison 11:15 Genetics of Lamb Survival David Thomas Professor, Department of Animal Sciences, CALS, UW-Madison Noon Lamb Barbecue Lunch $8.00/adult, $5.00/child under 12 1:00 Raising Lambs from Weaning to Market Claire Mikolayunas Extension Specialist, Department of Animal Sciences, CALS, UW-Madison 1:45 Why are Lamb Prices so High? Dave Johnson Equity Cooperative Livestock Sales Association 2:15 Dairy Sheep Research Discussion Bring your ideas for on-farm and station research regarding dairy sheep. 2:45 Adjourn and Open Barn Please visit the sheep barn and watch milking at 4:00 pm Spooner Sheep Day is sponsored by the College of Agricultural and Life Sciences (CALS) of the University of Wisconsin-Madison and Cooperative Extension of the University of Wisconsin- Extension. 1

SPOONER AGRICULTURAL RESEARCH STATION UPDATES Phil Holman Spooner Agricultural Research Station University of Wisconsin-Madison Spooner, Wisconsin The 2010 season was very productive in terms of receipts from milk, breeding stock, market lambs, sale of excess corn and soybeans. After the 2010 milking season, the milkhouse was remodeled. New door frames, doors, and interior wall panels were installed by the station staff. Doors and frames are a composite plastic to prevent rot. Also, a larger bulk tank was installed. In spring of 2011, a logging project was completed on the station property in accordance with a DNR Forestry Plan. All aspen were harvested, as well as thinning several pine species locations. Most noticeable will be the removal of a timber strip between the barn and several pastures. Young white pines were replanted in that timber strip. The timber harvest will be completed this winter. 2011 growing season notes so far: o Good yields and quality were observed with first cut alfalfa and alfalfa/grass harvest. First cut was chopped. Second cut yielded more round bales than we will use. Third cut was harvested last week and used to finish filling the silo. New seeded alfalfa looks excellent. o Several pastures were hayed in June because pastures were ahead of sheep forage needs. o Corn and soybean planting was late due to frequent rains in late April and early May. There was a dry spell in late June and early July but since then we have had excessive rains which have the crops looking good. Crop Research Includes o Variety trials of Corn, Alfalfa, Soybeans, Italian Ryegrass, Perennial Ryegrass, Oats, and Barley. o Two Switchgrass trials continue with a new one was seeded in 2011. o Sulfur needs of Corn at different soil ph trial o Soybean seeding rate trial Horticultural and Natural Resource Research Trials o Wine Grape Variety Trial o High Tunnel Fall Raspberry Production Trial o Replant of Hybrid Poplar and Hybrid Willow into the former Hybrid Poplar area o Hazelnut Production Trial 2

PROFITABILITY OF DAIRY SHEEP OPERATIONS Larry Tranel Extension Dairy Specialist Northeast and Southeast Iowa Iowa State University Extension and Outreach Introduction A review of profitability on dairy sheep operations is a difficult process due to the relatively few dairy sheep flocks producing milk and the ability to obtain accurate records of data necessary to analyze profitability. With that in mind, four Wisconsin dairy sheep operations were asked to submit data using the Dairy Sheep TRANS financial analysis software. The following discussion is based on the data in Tables 1 and 2 on the pages that follow. The data is broken into two groups. The data set on the left contains the average of the four farms. The data on the right contains the data of the top 50% or in this case, only the top two farms. These four dairy sheep operations exhibited a wide range of profitability from being somewhat profitable (depending on the definition) to being not so profitable and showing substantial losses from the net income from operations, return to labor and return to equity. Thus, it is important to realize that RISK is associated with management and operation of dairy sheep enterprises. The average of the four farms had 41 productive acres as part of the operation with the more profitable ones (Top 50%) at 54 acres per farm. The average had 225 ewes while the more profitable ones had 330 ewes or a significant 47% more ewes per farm. Total assets on the average farm was $1,447 per milking ewe while the more profitable ones had only $1,120 of assets per ewe. The average milk price was $66.17 and was pretty similar to the $64.84 milk price of the more profitable operations. Milk sales were $318 and $322 per ewe for the average and more profitable respectively. Total cash income was $424 and $411 per ewe, respectively. On the expense side of the equation, all the expense items were lower on the more profitable operations indicating more astute cost control measures to operation of a more profitable farm. Net cash income was negative in both the average farm (-$106 per ewe) and the more profitable (-$20 per ewe) operations. Inventory changes of -$183/ewe and +$16,891 were recorded for the average and more profitable, respectively and these were significant, mostly stemming from feed inventory changes and breeding livestock sales. After subtracting a charge for equity ownership and interest at 6%, the average return to labor was -$40,979 per operation or -$183 per ewe. For the more profitable farms, the return was still negative at -$11,186 with losses $29,793 lower than the average of the operations. Labor Efficiencies These dairy sheep operations averaged -$13.42 per labor hour while the more profitable ones averaged -$3.25 per labor hour going into the operation. There was 17.82 hours of labor average 3

per ewe while the more profitable farms averaged 15.15 hours of labor per ewe, a significant 17.6% difference that could play a key role in why the more profitable farms could handle 47% more ewes. Like any dairy operation, labor efficiency plays a large part in profitability and this analysis shows striking differences in all labor efficiency categories. The adjusted gross return per FTE (Full Time Equivalent) was $55,732 on average and $77,762 for the more profitable farms. The return to all labor per FTE was -$23,743 on average but still only $2,289 for the more profitable farms. The number of does per FTE Laborer (3,000 hours annually) was 125 on average but was 166 or 33% higher on the more profitable farms. Hundredweights sold per FTE were also significantly more on the more profitable farms by 38.8%. This increase in labor efficiency for all these measures was greater percentage wise than even the purchased feed cost differences (24%) between the average farm and the more profitable farms. Thus, the more profitable farms are much more labor efficient than the average farm. One of the more intriguing pieces of this analysis is the fact that total purchased feed costs were $273 per ewe on average but only $220 per ewe for the more profitable operations. The more profitable operations had 47% more ewes on only 31.7% more land and yet their feed costs were$53 lower per ewe. Errors in feed inventory adjustments from beginning to end of year could be a factor as producers estimated these figures as best they could. However, these feed cost differences are highly significant. Milk Production Costs and Profitability The average dairy sheep operation had a gross income of $66.17 per hundredweight. The gross expenses was $188.76 for a net cash income of $-122.60. This is of great concern as even a doubling of the gross income would still not cover the gross expenses of these operations, on average. However, the more profitable farms only had gross expenses per hundredweight of $89.74 so their net income loss per hundredweight was only $-24.90. Pounds of milk sold per doe was 473 for the average of the four farms but 502 pounds of milk per doe for the more profitable ones or around 6% higher. Other efficiency and profit factors play a part and can be compared against the average and the more profitable farms in the tables. Rate of return was -21% on average and -9.6% for the more profitable farms. The operating profit margin was -159% on average and -23.8% for the more profitable farms. Asset turnover ratios were 28% on average and 42.6% for the more profitable farms. Summary Dairy Sheep operations face profit risk as this industry continues to try to get its feet on the ground and grow. This profit analysis in 2010 showed highly variable levels of profitability or lack of signifying that many management issues need to be discerned relative to labor efficiency, feed costs and genetic improvement especially to increase both does managed per FTE, purchased feed costs and milk produced per doe. 4

2010 is one review in time. More dairy sheep profitability review is encouraged in future years to further assist this industry become more viable. Current and potential dairy sheep producers are encouraged to look at their current and potential profitability in order to reduce investment risk as new operations are built and current operations are expanded. Credits: This author would like to thank the dairy sheep operations who participated in this financial analysis. In addition, much appreciation needs to be given to Dr. Claire Mikolayunas, UW-Extension Sheep Specialist, for her initiation and thoughtful review of this Dairy Sheep Profitability Project. 5

Table 1. Dairy Sheep Records, 2010 Average Per Ewe Dairy Sheep Records Top 50% Top 50% 4 Farms 2010 2 Farms Per Ewe Productive Crop Acres 41 0.18 Productive Crop Acres 54 0.10 Average Number of Ewes 225 1.00 Average Number of Ewes 330 Total Assets on Farm $324,798 $1,447 Total Assets on Farm $369,451 $1,120 Milk Price $66.17 Milk Price $64.84 Milk Hundred weight Equiv. 1,462 6.51 Milk Hundred weight Equiv. 2,332 7.07 Milk Hundredweights 1,086 4.84 Milk Hundredweights 1,639 4.97 Milk Sales $71,297 $318 Milk Sales $106,294 $322 Cull Ewe Sales $2,291 $10 Cull Ewe Sales $4,582 $14 Lamb Sales $13,158 $59 Lamb Sales $19,266 $58 Crop Sales $0 $0 Crop Sales $0 $0 Other Income $8,477 $38 Other Income $5,441 $16 Total Cash Income $95,223 $424 /cwt.eq. Total Cash Income $135,582 $411 Veterinary, Medicine $2,384 $11 $1.63 Veterinary, Medicine $2,152 $7 Dairy Supplies $4,827 $22 $3.30 Dairy Supplies $6,218 $19 Breeding Fees $307 $1 $0.21 Breeding Fees $0 $0 Feed Purchased $61,353 $273 $41.97 Feed Purchased $72,647 $220 Repairs $5,772 $26 $3.95 Repairs $6,044 $18 Seed, Chem, Fert $2,106 $9 $1.44 Seed, Chem, Fert $2,502 $8 Fuel, Gas, and Oil $922 $4 $0.63 Fuel, Gas, and Oil $1,079 $3 Utilities $5,911 $26 $4.04 Utilities $7,805 $24 Interest Paid (included in equity charge) $0 $0 $0.00 Interest Paid (in equity charge $0 $0 Labor Hired $18,186 $81 $12.44 Labor Hired $24,324 $74 Rent, Lease and Hire $1,949 $9 $1.33 Rent, Lease and Hire $2,387 $7 Property Taxes $2,451 $11 $1.68 Property Taxes $3,124 $9 Farm Insurance $2,833 $13 $1.94 Farm Insurance $3,216 $10 Other Cash Expense $10,085 $45 $6.90 Other Cash Expense $10,615 $32 Total Cash Expense $119,082 $530 $81.46 Total Cash Expense $142,112 $431 Net Cash Income -$23,859 ($106) -$16.32 Net Cash Income -$6,530 ($20) Inventory Change $808 $4 $0.55 Inventory Change $16,891 $51 Net Farm Income -$23,051 ($103) -$15.77 Net Farm Income $10,362 $31 Equity@ 6% $17,928 $80 $12.26 Equity@ 6% $21,548 $65 Return to Labor -$40,979 ($183) -$28.03 Return to Labor -$11,186 ($34) Inventory Adjustments--Feed -$2,958 ($13) -$2.02 Inventory Adjustments--Feed $4,055 $12 Supplies and Other $1,500 $7 $1.03 Supplies and Other $3,000 $9 Breeding Livestock $2,163 $10 $1.48 Breeding Livestock $8,650 $26 Income Change $704 $3 $0.48 Income Change $15,705 $48 Prepaid Expenses $0 $0 $0.00 Prepaid Expenses $0 $0 Accounts Payable $0 $0 $0.00 Accounts Payable $0 $0 Machinery & Equipment $1,500 $7 $1.03 Machinery & Equipment $0 $0 Land and Buildings $6,250 $28 $4.28 Land and Buildings $0 $0 Other Adjustments $2,468 $11 $1.69 Other Adjustments $4,937 $15 Expense Change -$10,218 ($46) -$6.99 Expense Change -$4,937 ($15) Capital Purchases Minus Sales Adj. $10,115 $45 $6.92 Capital Purchases Minus Sales Adj. $3,750 $11 Depreciation COST $18,621 $83 $12.74 Depreciation COST $2,736 $8 Depreciation FM Value $5,593 $25 $3.83 Depreciation FM Value $3,140 $10 Unpaid Labor Cost $37,500 $167 $25.65 Unpaid Labor Cost $45,000 $136 Unpaid Labor Hours 4,000 17.82 hrs/ewe Unpaid Labor Hours $5,000 15.15 Labor Full Time Equivalents $1.83 Total Labor Labor Full Time Equivalents 2.17 Labor Earnings Per Hour -$13.42 Labor Earnings Per Hour ($3.25) -$0.01 6

Table 2. Dairy Sheep Records, 2010 Average Per Ewe Dairy Sheep Records Top 50% Top 50% 4 Farms 2010 2 Farms Per Ewe Gross Income per Cwt. Eq. $66.17 Gross Income per Cwt. Eq. $64.84 $0.20 Gross Expense per Cwt. Eq. $188.76 Gross Expense per Cwt. Eq. $89.74 $0.27 Net Income per cwt. -$122.60 Net Income per cwt. ($24.90) -$0.08 Cash Income-- $95,223 $424 Cash Income-- $135,582 $411 Adjusted Income $704 $3 Adjusted Income $15,705 $48 Total Income $95,927 $427 Total Income $151,287 $458 Cash Costs (w/o interest) $119,082 $530 Cash Costs (w/o interest $142,112 $431 Adjusted Costs -$104 $0 Adjusted Costs ($1,187) ($4) Overhead Costs $55,428 $247 Overhead Costs $66,548 $202 Total Costs $174,406 $777 Total Costs $207,473 $629 RETURN OVER COSTS -$78,479 -$350 RETURN OVER COSTS ($56,186) ($170) Adj. Gross Return per FTE Labor.. $51,732 Adj. Gross Return per FTE Labor.. $77,762 Return to All Labor per FTE Labor... -$23,743 Return to All Labor per FTE Labor... $2,289 Number of Does per FTE Labor... 125 Number of Does per FTE Labor.. 166.25 Cwts. of Milk Sold per FTE Labor... 607 Cwts. of Milk Sold per FTE Labo 843 Pounds of Milk Sold per Doe... 473 Pounds of Milk Sold per Doe... 502 Productive Crop Acres per Doe... 0 Productive Crop Acres per Doe. 0.17 Capital Cost per Doe $129 Capital Cost per Doe $78 All Labor Costs per Doe... $277 All Labor Costs per Doe... $208 Fixed Cost per Doe (DIRTI) $191 Fixed Cost per Doe (DIRTI) $119 Capital Invested per Doe $1,687 Capital Invested per Doe $1,092 Net Farm Income per Crop Acre... ($979) Net Farm Income per Crop Acre $164 Lbs. Milk Produced per Crop Acre 2468 Lbs. Milk Produced per Crop Ac 3,022 Adj. Gross Cash Income/Crop Acre $2,107 Adj. Gross Cash Income/Crop Acre $2,789 Machinery Investment/Crop Acre $573 Machinery Investment/Crop Acre $405 Fuel, Gas and Oil Cost/Crop Acre.. $24 Fuel, Gas and Oil Cost/Crop Acre.. $22 Repair Cost per Crop Acre... $161 Repair Cost per Crop Acre... $117 Fert/Chem/Seed Cost/Crop Acre $56 Fert/Chem/Seed Cost/Crop Acre $50 Livestock over Total Investment % 23% Livestock over Total Investmen 27% Cash Exp./Cash Inc.w/o Labor&Int. 121% Cash Exp./Cash Inc.w /o Labor&Int. 87% All Labor as Percent of Total Costs 31% All Labor as Percent of Total Costs 33% Fixed Cost as Percent of Total Cost 20% Fixed Cost as Percent of Total Cost 18% **Net Farm Income From Operations ($23,051) **Net Farm Income From Operatio $10,362 **Rate of Return on Assets -21% **Rate of Return on Assets -9.6% **Rate of Return on Equity -21% **Rate of Return on Equity -9.6% **Operating Profit Margin -159% **Operating Profit Margin -23.8% **Asset Turnover Ratio 28% Dairy Sheep TRANS 2007 **Asset Turnover Ratio 42.6% **Operating Expense Ratio... 188% by Dr. Larry Tranel **Operating Expense Ratio... 92.7% **Depreciation Expense Ratio... 10% Dairy Field Specialist **Depreciation Expense Ratio... 2.2% **Net Farm Income Ratio... -98% **Net Farm Income Ratio... 5.0% Dairy TRANS Profit Status is Dairy TRANS Peformance Rating by Larry Tranel, Dairy Field Specialist, Iowa State University Extension www.extension.iastate.edu/dubuque/info/dairy+publications.htm Estimated % Interest Paid 7

2011-2012 SHEEP MILK MARKET UPDATE Paul Haskins Director of Marketing Wisconsin Sheep Dairy Co-op River Falls, Wisconsin, USA 2011 Review 2011 has seen a great deal of upheaval in the market for both fluid and frozen milk. This market uncertainty is occurring not only in Wisconsin, but nationwide. The Wisconsin Sheep Diary Co-op (WSDC) was forced to weather two significant market events in 2011: WSDC s largest fluid milk customer reduced shipment volume by 30% compared to 2010 levels. WSDC s largest frozen milk customer suspended shipments after only 80,000 lbs delivered on a 150,000 lb contract. Overall, WSDC has experienced an 18% drop in the overall volume of milk sold (fluid and frozen) in 2011. In order to keep farms operating in 2011, WSDC was able to increase fluid shipment levels (sales and own product utilization) from about 810,000 lbs in 2010 to 900,000 lbs in 2011. WSDC s frozen milk sales dropped from 290,000 lbs in 2010 to 80,000 lbs in 2011. Factors Negatively Influencing Dairy Plants Decision To Purchase Sheep Milk Sheep milk has become a fairly tough sell to plants and cheese makers for the following reasons: Uncertainty in the economy and specifically the high end foodservice market. Inability of many plants to obtain financing for the purchase. Strength in domestic and international dairy markets has made commodity and specialty cheese made from cow s milk much more profitable in recent years and sheepmilk products less so. Plant capacity and milk segregation issues. Positive Sheep Milk Market Factors WSDC was able to increase fluid shipment volume by 10% over 2010 levels in 2011 via new customers and slight increases in volumes to some existing customers. There is a definite market demand for sheep milk products. WSDC sales of branded and private label cheese increased by 75% in 2010 and another 50% to date in 2011. WSDC plans to expand products and customer base in 2012, providing milk for up to 8 different plants in WI and MN for both milk sales and WSDC products. 8

The Future of Frozen Milk 2011 has seen a tremendous drop in frozen milk demand from existing and potential customers nationwide. The underlying reasons for this drop as reported by WSDC customers are: Rapidly developing local fluid milk supply in NY and CA. Increasing competition in the frozen milk market from large producers. Inability of WSDC to finance purchases long term for customers. Poor quality reputation for WSDC frozen milk. WSDC is planning a very limited involvement in the frozen milk market in 2012 with possibly no involvement at all. What Does This Mean For Prospective and Existing Farms? Market trends are going to positively and negatively affect farms depending on their size and location relative to where fluid milk is needed. Some expected trends: Consolidation of production with relatively fewer farms shipping larger volumes of milk. Decreased opportunities to provide frozen milk. Decreased acceptance of new patrons by WSDC except in areas and/or routes of need. Projected 10% growth in market in 2012 with more growth possible depending on success of particular products. 9

LAMB MORTALITY AT THE SPOONER AGRICULTURAL RESEARCH STATION BETWEEN 1989 AND 2011 Yves Berger Researcher Spooner Agricultural Research Station University of Wisconsin -Madison Introduction The data presented in this article cover 23 lambing seasons and close to 14,000 lambs. It is important to know that the data include all lambs, born dead or alive, even late abortions. Lambs aborted early in gestation are not included. This approach allows for an accurate calculation of the prolificacy of the ewes but will increase the mortality count. The information gathered is difficult to interpret because, over the years, the type of breeds as well as the management changed drastically, going form meat breeds (Hampshire, Suffolk, Targhee) to highly prolific maternal breeds (Romanov and Finn) and finally to highly specialized dairy breeds (East Friesian and Lacaune). It is interesting, however, to look at the common constant to all breeds and the effect of each breed on the overall mortality of lambs. Overall mortality Table 1 and Graph 1 show that over the years a total of 14.4% of the lambs died between the age of 0 to 90 days (1993 lambs for 13,832 lambs born). Forty seven percent of the dead lambs were born dead, died during birth or died shortly after birth. The percentage of lambs dead at birth or not surviving 1 day of age has been fairly constant throughout the years and seems to be independent of the breed or the type of management. The higher peak in 1997 corresponds to a higher rate of abortion or lambs born weak due to an outbreak of campylobacteriosis (vibriosis) which prompted the establishment of a yearly vaccination program. Another 21% of those lambs died of pneumonia the leading cause of mortality of young lambs. Between 1989 and 1999 the overall mortality was at or below 10% but for 1997. During this period the flock consisted of meat breeds and of highly prolific breeds managed in an accelerated lambing system. Even with large liter sizes the mortality was low and the incidence of pneumonia practically inexistent. Mortality of lambs really started to increase in 1999 when the genetic make up of the flock was changed toward a higher and higher percentage of specialized dairy breeds (East Friesian and Lacaune) with a management oriented toward maximum milk production, with early winter lambing, removal of lambs from their mother a few days after birth and more and lambs raised on milk replacer. The percentage of lambs dying of pneumonia also increased with the higher percentage of dairy breed. In 2011 with all ewes being 100% dairy and all lambs raised on milk replacer, the mortality rate between 0 and 90 days reached 28.8% with 13.2% of all lambs born dying of pneumonia. 10

Causes of death 0 days Table 2 shows that 47% of all dead lambs did not survive 1 day of age. Lambs dead in utero (rotten, mummified, water belly, deformed ) make up close to 1/3 of those lambs. The cause of this high number is difficult to pin point and it would be interesting to know whether it occurs on other farms. One possible explanation is the high prolificacy of the breeds of ewes at the Spooner Research Station. The large number of lambs in the uterus creates competition for a given number of cotyledons leading to some lambs being robbed of nutrients and therefore dead lambs, premature lambs, weak lambs or very small lambs. Difficult parturitions accounted for another 1/3 of the death. Dystocia occurred mostly in ewes carrying 3 or more lambs often creating abnormal presentation of the lambs at birth. Deaths attributed to mismothering such as lambs drowning in the amniotic sacs or lambs laid on by the mother during the birth of another lamb represent another 10% of the death at birth. Another 6.5% of the lambs were born normal but froze shortly after birth when the mother were having her second or third lamb. 1-10 days Eleven percent of all mortality occurred between 1 and 10 days of age. The leading causes of mortality during this period were: - Smothered by mothers in jugs (26.8%). Although the jugs are of the recommended size (4 x 5 ) with feed and water not taking any floor space, some ewes always manage to lay down on 1 or 2 lambs especially in large liters. This is certainly a management problem. Jugs maybe should be bigger. - Lambs born weak but not dying the first day, lambs not getting enough to eat and lambs euthanized for various reasons account for another 35 % of the death before 10 days of age. - Pneumonia starts to occur in those lambs and account for 12% of the deaths. 10-30 days Sixteen percent of all deaths occurred between 10 and 30 days of age with 2 leading causes: - Abomasum bloat is the cause of 24% deaths in this group. Abomasum bloat due to the fermentation of milk in the abomasum is the cause of sudden death of the fastest growing lambs raised on milk replacer. - Pneumonia claimed 33% of the death in this age group. - Lambs not eating sufficiently caused 12% of the deaths. 30-90 days Twenty five percent of the overall mortality occurred between 30-and 90 days of age. The causes are varied and diverse such as difficult weaning, accidents and were often unknown but more than half (59%) of the mortality was due to pneumonia. 11

Effect of the parity of the ewes on mortality of lambs (Table 3) Lambs born from primiparous ewes had a higher mortality rate than lambs born from older ewes (19.7% vs. 12.7%) and were more susceptible to pneumonia than lambs born from older ewes (7.9% vs. 1.6%). A season effect cannot be discounted since young ewes generally lamb later than older ewes (March-April vs. January-February). The wide daily temperature fluctuations at this time of the year contribute to the development and build up of Pateurella hemolytica, the leading agent in pneumonia of young lambs. The suspicion of lower quality colostrum in primiparous ewes leading to a lesser immunity of young lambs was discarded after that the Total Protein of 7 lambs less than 5 days old from primiparous ewes showed normal values. Effect of the sex of lambs (Table 4) Male lambs had a slightly higher mortality than female lambs and were somewhat more susceptible to pneumonia. Effect of the type of birth (Table 5) Lambs born in liter superior to 3 had a greater chance of dying before 1 day of age because of the greater number of dystocia and of the greater number of lambs dead before birth. The greater percentage of lambs born single dying of pneumonia certainly came from the fact that most single lambs are born from primiparous ewes, therefore more susceptible to pneumonia. Effect of the type of rearing (Table 6) Over the years an identical number of lambs were either raised by their mothers or artificially raised on milk replacer. Lambs raised on milk replacer had a higher mortality (10%) than lambs raised by their mothers (2.5%). Artificially raised lambs also had a higher incidence of pneumonia but pneumonia accounted for only 42 % of the deaths whereas in the naturally raised lambs pneumonia accounted for 72% of the deaths. Effects of the genotypes of the ewes and sires (Table 7) This table presents the most interesting data. The mortality rate of lambs born from any type of ewes (dairy and non dairy) was fairly low (6-10%) when they were sired by non dairy rams. The incidence of pneumonia in those lambs was also very low. The exception would be for lambs born from very high percentage dairy ewes such as East Friesian or East Friesian-Lacaune crosses. However, the mortality of lambs as well as the incidence of pneumonia increased sharply as soon as the same dairy ewes were bred by dairy rams. The mortality of lambs seemed to increase proportionally with the percentage of dairy genetics. Lambs born from half dairy ewes had a lower mortality rate (17%) than lambs born from higher percentage dairy ewes (24-26%). It appears that lambs with a high percentage dairy genetic makeup are less vigorous at birth and more susceptible to environmental diseases and stress. 12

Conclusion In a sheep dairy operation more than 2/3 of the total income can come from milk production. It is therefore understandable that a producer seeks to obtain the maximum milk production. In order to achieve this high milk production, some management techniques need to be put in place such as using high percentage dairy ewes, early winter lambing, removal of lambs as soon as 1-2 days after birth and rearing of all lambs on milk replacer. Those techniques can be unfavorable to the survivability of lambs if stress is induced on the lambs and/or if the environmental factors propitious to the propagation and build up of bacteria prone to induce pneumonia are not well controlled. Not all farms would be able to have a perfect control of those factors and could expect a high mortality rate. If this mortality rate is above a certain tolerance level and control of all aspect of hygiene cannot be achieved, decisions in the change of management should be taken such as reducing the percentage of dairy genetic, choosing a more favorable lambing season, and letting the ewes raising their lambs. Of course, the overall milk production will be adversely affected. 13

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Percentage Table 1. Total mortality of lambs from 1989 to 2011 Number of lambs born Total dead Dead <1 day Dead 1-10 days Dead 10-30 days Dead 30-90 days Dead of pneumonia 13832 1993 937 221 344 491 426 14.4% 6.8% 1.6% 2.5% 3.5% 3.1% Graph 1. Total mortality over the years 35 30 25 Total mortality Dead <1 day Pneumonia 20 15 10 5 0 Years 14

Table 2. Main causes of mortality (percent of total) Causes of death <1 day 1-10 10-30 30-90 TOTAL old days days days Total dead 937 47% 221 11% 344 17.2% 491 24.6% Born dead (rotten, malformed, mummified ) 295 14.8% 14.8% Born from sick ewes 23 1.2% 1.2% Born alive weak 70 3.5% 17.9% 4.4% Difficult lambing 315 15.8% 15.8% No rupture of amniotic sac or laid on by mother 97 4.9% 56 2.8% 7.7% Hypothermia or Starvation 59 3% 32 1.6% 29 1.5% 32 1.6% 7.7% Euthanized 20 1% 29 1.5% 29 1.5% 14.7% 4.7% Bloat or overeating 12.6% 81 4.1% 3.2% 4.9% Accident 5.3% 15.8% 15.8 1.9% Pneumonia 26 1.3% 113 5.7% 287 14.4% 21.4% Other 50 2.5% 2.5% Unknown or not recorded 58 2.9% 44 2.2% 77 3.9% 90 4.5% 13.5% Table 3. Effect of the parity of the ewes on mortality of lambs (without year 1989) (percent of born) Parity # born Total < 1 day 1-10 10-30 30-90 Pneumonia dead old days days days 1 3389 656 207 82 124 243 268 19.4% 6.1% 2.4% 3.7% 7.1% 7.9% 2+ 10048 1277 637 185 217 238 164 12.7% 6.3% 1.8% 2.2% 2.4% 1.6% 15

Table 4. Effect of the sex of lambs (percent of born) Sex # born Total < 1 day 1-10 10-30 30-90 Pneumonia dead old days days days Male 6919 1080 485 125 193 277 237 15.6% 7% 1.8% 2.8% 4% 3.4% Female 6907 887 382 148 149 208 190 12.8% 5.5% 2.1% 2.2% 3% 2.8% Table 5. Effect of the type of birth (percent of born) Type of # born Total < 1 day 1-10 10-30 30-90 Pneumonia birth dead old days days days 1 1704 271 90 25 64 92 79 15.9% 5.3% 1.5% 3.8% 5.4% 4.6% 2 7347 954 322 148 192 292 234 13% 4.4% 2% 2.6% 4% 3.2% 3 3993 616 380 80 65 91 54 15.4% 9.5% 2% 1.6% 2.3% 1.4% 4-5-6-7 751 140 88 23 22 7 8 18.6% 11.7% 3% 2.9%.9% 1% Table 6. Effect of the type of rearing (percent of raised) Type of # raised Total 1-10 10-30 30-90 Pneumonia rearing dead days days days Natural 6033 152 0 12 140 109 2.52 0.2% 2.3% 1.8% Artificial 6399 619 77 231 311 260 9.7% 1.2% 3.6% 4.9% 4.1% 16

Table 7. Effect of the genotypes of ewes and sires (percent of born) Dam Breed Romanov-Finn crosses Sire # born Total dead < 1 day old Pneumonia breed no dairy 2642 307 11.6% 206 7.8% 5.2% Targhee no dairy 685 69 10% 47 6.9% 1.1% Dorset Type no dairy 1076 73 6.8% 42 3.9% 3.3% dairy 921 94 10.2% 53 5.8% 8.9% ½ EF or less no dairy 1811 162 8.9% 105 5.8% 15.8% dairy 666 118 17.7% 38 5.7% 517 7.7% ½ L or less no dairy 187 17 9% 9 4.8% 0 0% dairy 270 47 17.4% 16 4.9% 14 5.2% > 1/2 EF or ¾ EF no dairy 310 24 7.7% 14 4.5% 2.6% dairy 313 74 23.6% 26 8.3% 31 9.9% >1/2 L or ¾ L no dairy 135 9 6.7% 6 4.4% 0 0% dairy 146 35 24% 12 8.2% 12 8.2% 7/8 EF or EF no dairy 173 27 15.6% 4 2.3% 3 1.7% dairy 545 141 25.9% 14 2.6% 52 9.5% 7/8 L or L no dairy 44 4 9.1% 0 0% 2 4.5% dairy 108 25 23.1% 4 3.7% 9 8.3% ExL or LxE no dairy 1416 220 15.5% 107 7.5% 32 2.3% dairy 2077 473 22.8% 126 6% 162 7.8% 17

GENETICS OF LAMB SURVIVAL David L. Thomas Department of Animal Sciences University of Wisconsin-Madison Madison, Wisconsin, USA Summary Lamb survival is an economically important trait in commercial sheep production. Lamb survival exhibits a large amount of individual and maternal hybrid vigor, and breed differences exist for lamb survival. Therefore, the greatest opportunities to genetically improve lamb survival are to utilize breeds known for high lamb survival in mating systems that produce crossbred lambs from crossbred ewes. Low estimates of direct and maternal heritabiliteis for lamb survival, a negative correlation between direct genetic and maternal genetic effects for lamb survival, and lack of effective selection criteria for ewe rearing ability suggest that selection for improved lamb survival will be difficult at the present time. Development of improved selection criteria and genomic selection may result in reasonable amounts of selection response in the future. The Problem The most recent report on sheep death losses in 2009 from the USDA indicates that lamb mortality represents a major economic loss to the sheep industry. USDA estimates that 3,690,000 lambs were born in 2009 in the U.S. (NASS, 2010b), and 228,500 of these lambs died from nonpredator causes (6.2% lamb mortality) (NASS, 2010a). In many of the western states where most of the sheep are located, lambs are not counted until they are docked at a few weeks of age. Since many lamb deaths take place very early in life (see below), the 6.2% estimate of lamb mortality is very much an underestimate of the true lamb death loss in the U.S. In Wisconsin, it was estimated that 8,700 lambs died from non-predator causes out of a total crop of 75,000 lambs in 2009 (11.6 %). At an average market value of $112 per lamb (WASB, 2010), lamb death losses resulted in a loss of potential income of $974,400 to Wisconsin sheep producers in 2009. With market lamb values substantially higher in 2011 (~$240 per lamb), this same lamb death loss in 2011 would result in a loss of potential income of $2,088,000 to Wisconsin sheep producers. The majority of lamb deaths occur early in the lamb s life. A study of lamb deaths from birth to weaning at 30 or 60 days of age from 1989 through 1997 at the Spooner Agricultural Research Station, University of Wisconsin-Madison, USA reported a 9.9% mortality (536 deaths prior to weaning/5425 births) (Berger, 1997). Of the total deaths prior to weaning, 77% (411/536) of the lambs were born dead or died within the first 3 days of life. Southey et al. (2001) reported that of 8,642 lambs born in a flock at the USDA Meat Animal Research Center, Clay Center, Nebraska, USA, 18.8% died by 120 days of age, and 81% of these deaths occurred before weaning at 50 days of age. The major causes of lamb deaths in the U.S. in 2009 were: weather related, primarily hypothermia (25.6% of deaths), lambing problems (14.5%), respiratory problems (12.6%), internal parasites (7.9%), and the disease enterotoxemia (6.3%) (NASS, 2010). 18

There are several Best Management Practices for improving lamb survival such as health management and vaccination programs, proper nutrition of pregnant ewes, lambing management, prevention of predation, and proper lamb nutrition. Good management practices are essential for high lamb survival, but breed choice, selection, and crossbreeding may offer ways to genetically improve lamb survival even further. Breed Choice There are reports in the scientific literature of differences between breeds for lamb survival, which is a good indicator that lamb survival is determined, to some extent, by the genotype of the lamb and/or the dam. Table 1 presents results from some published research studies of the survival of F1 (firstcross) lambs sired by different breeds of rams. Within each study, the breed of dam of the lambs was the same. Therefore, the maternal breed environment is the same for each lamb, and differences between lambs from different breeds of sire is an estimate of one-half the direct genetic breed differences for survival. Table 1. Breed of sire means for lamb survival from selected studies. Breed of sire of the lamb a No. of sires/lambs Survival period Survival, % Reference Oxford?/1182 67.2 Birth 8 to 14 Hampshire?/982 63.2 weeks Suffolk?/1014 58.1 Texel 19/? Birth 51 86 Suffolk 20/? days 77 Barbados 12/168 91.9 Finnsheep 12/148 91.4 Birth 56 St. Croix 12/178 89.5 days Combo-6 12/173 82.3 Booroola Merino 12/162 80.7 Romanov 19/? 94.1 Finnsheep 23/? 93.0 Birth 56 Texel 21/? 90.7 days Dorset 20/? 90.0 Montadale 19/? 89.1 Smith, 1977 Leymaster and Jenkins, 1993 Bunge et al., 1993 Freking and Leymaster, 2004 a Within a study, the sires were bred to the same breed of ewe. All lambs were first crosses with the breed of dam in common. 19

The studies presented in Table 1 are a select group of studies that have sampled a large number of rams and produced a large number of lambs from each breed. Between studies, the difference in percentage lamb survival between the highest and lowest sire breed ranged from 5.0% to 11.2%. This means that for every 100 lambs born in a flock, the use of the breed of sire with the highest lamb survival rate would be expected to result in 5 to 11 more lambs surviving than the breed of sire with the lowest lamb survival rate or approximately $680 to $1,500 more income. Determining which breed of sire is genetically superior for lamb survival is not easy. The results of only four studies are presented in Table 1. It would be desirable to have additional studies with these same breeds to determine if the results presented here are repeatable as well as more studies with additional breeds. However, given these limitations, the studies presented in Table 1 do give some indication of breed genetic differences. It appears that Suffolk sires may be poorer for lamb survival and Finnsheep, Romanov, and the hair breed sires of Barbados and St. Croix may be superior for lamb survival compared to some other breeds. Breed differences for lamb survival can also be estimated by observing differences in survival of lambs from dams of different breeds or crossbreds. Since ewes provide both genes and a maternal environment to their lambs, such comparisons give estimates of both direct genetic breed effects and maternal genetic breed effects. It takes well-designed experiments to disentangle the direct genetic effects from the maternal genetic effects. Crossbred ewes containing Finnsheep or Romanov breeding have been shown to produce lambs with higher survival rates in several studies. Table 2 presents results from the review of Thomas (2010) on the performance of Northern European short-tailed breeds of sheep, of which the Finnsheep and Romanov breeds are members, in studies conducted in Canada and the U.S. Table 2. Mean lamb survival to weaning, averaged across studies, of Finn-cross and domestic/domestic-cross lambs in North America Survival, % Finn - Domestic % Finn Finn Domestic Diff. a % diff. b No. of studies 25% Unadj. c 77 80-3 -4 7 Adj. d 12.5% Unadj. c 75 87 69 86 +6 +1 +9 +1 3 6 Adj. d 85 82 +3 +4 2 a Difference between the Finn and Domestic means in each row. b ((Finn mean Domestic mean)/domestic mean) * 100. c Lamb survival is unadjusted for lamb s litter size. d Lamb survival is adjusted for lamb litter size by including type of birth or type of birth and rearing in the model or lambs were raised from birth artificially on milk replacer. 20

Table 2 presents the lamb survival of one-quarter and one-eighth Finnsheep lambs from onehalf and one-quarter Finnsheep ewes, respectively, compared to non-finnsheep lambs. Finnsheep ewes give birth to larger litters than almost all other breeds in North America, and it is well known that percentage of deaths increases as the number of lambs in the litter increases. When the number of lambs in the litter is not considered, one-quarter Finnsheep lambs from one-half Finnsheep ewes have a lower lamb survival than domestic breeds or crossbreds. However, this appears to be an effect of the increased litter size of one-half Finnsheep ewes. If the data are adjusted for litter size, the one-quarter Finnsheep lambs have 9% higher survival rates than the domestic breed lambs, i.e. within the same litter size, lambs of Finnsheep breeding are expected to have greater lamb survival than lambs of domestic breeding. As would be expected, the Finnsheep advantage for lamb survival, adjusted for litter size, is less for one-eighth Finnsheep compared to one-quarter Finnsheep lambs (Table 2). The positive effect of Finnsheep breeding on lamb survival appears to be totally due to the Finnsheep genes provided to the lamb (direct genetic effect) because the Finnsheep maternal effect for lamb survival is estimated to be negative (Thomas, 2010), largely due to lower milk production of Finnsheep ewes compared to other breeds. Composite breeds of sheep containing Finnsheep breeding have been developed in North America: Outaouais Arcott (49% Finnsheep), Rideau Arcott (40% Finnsheep), and Polypay (25% Finnsheep). Due to their Finnsheep composition, these breeds would be expected to have higher lamb survival than most other familiar breeds or crosses in North America. The Romanov is one breed which may be superior to the Finnsheep for lamb survival. A large study conducted at the U. S. Meat Animal Research Center, Clay Center, Nebraska, USA (Casas et al., 2004) found that lambs from one-half Romanov ewes had a greater lamb survival (unadjusted for litter size) than lambs from one-half Finnsheep ewes (87.3 vs. 85.4%) even though the one-half Romanov ewes had a greater litter size than the one-half Finnsheep ewes (2.20 vs. 2.05). There also is evidence that suggests that breeds traditionally managed under low-input or noinput management systems at lambing time (e.g. hill breeds of U.K.) have greater lamb survival than breeds traditionally managed intensively at lambing time (Dwyer and Lawrence, 2005; Dwyer, 2008). In the study of Dwyer et al. (1996), Scottish Blackface and Suffolk embryos were transferred to Scottish Blackface and Suffolk ewes so that all four combinations of ewe breed and embryo breed were represented. All ewes received a single embryo. Ewe breed had little effect on lamb behavior shortly after birth. Blackface lambs from both breeds of ewe stood twice as quickly and were more likely to suckle within the first 2 hours of birth than Suffolk lambs, suggesting the probability of greater lamb survival of Blackface lambs. Many breeds have not been adequately evaluated for productive performance. All breeds, including those that have been well-evaluated in the past, change genetically over time due to directed selection or random chance (genetic drift). Therefore, there will always be a need for well-designed experiments to compare available breeds of sheep under common management systems for all production traits including lamb survival. 21

Selection In order for genetic progress to be made for any trait, genetic variation must exist for the trait (e.g. the trait has to have a heritability greater than zero). Heritability is an estimate of the proportion of phenotypic variation that is due to additive genetic (breeding value) variation. Perhaps more simply stated, heritability is an estimate of the proportion of the differences between animals in performance for a trait that are due to their genetic differences. If there are no genetic differences between animals in a population, there will be no progress from selection. Neal Fogarty, a sheep researcher recently retired from the New South Wales Department of Primary Industries, Orange, New South Wales, Australia, and his colleagues have published reviews of genetic parameter estimates for traits in sheep from the world scientific literature (Fogarty, 1995; Safari and Fogarty, 2003; Safari et al, 2005). Safari et al. (2005) reported heritability estimates for 29 sheep production traits from 326 studies. Sixteen of these studies estimated the direct heritability of lamb survival, and the average heritability of these 16 estimates was 0.03 the second lowest average heritability among the 29 different traits. This suggests that there is very little additive genetic variation for lamb survival. Within a breed, the primary reason that some lambs survive and some lambs die is due largely to environmental effects and only slightly to the genes that they possess, i.e. lambs that die almost always have negative environmental effects and lambs that survive almost always have positive environmental effects. In addition to the effect of a lamb s genes on its survival, consideration also needs to be given to the effect of the dam on the lamb s survival through the maternal environment that she provides. This includes the uterine environment provided to the fetus, the maternal care at lambing, and her milk production. The extent to which these traits are under genetic control and their relationship with lamb survival is captured in the maternal heritability for lamb survival. The review by Safari et al. (2005) reported an average maternal heritability for lamb survival of 0.05 from 8 studies. While this maternal heritability is still relatively small, it is almost twice the estimate for the direct heritability. Therefore, the genetic differences among dams for maternal traits are more important for lamb survival than the genetic differences among lambs for survival. A complicating factor in selection for lamb survival is that almost all studies have shown a negative correlation between direct genetic and maternal genetic effects for lamb survival, and some of the estimates are quite high (-0.61 to -0.75) (Everett-Hincks et al., 2005; Welsh et al., 2006; Cloete et al., 2009). The existence of this negative genetic correlation indicates that some genes that cause high lamb survival also result in poor maternal traits that negatively affect lamb survival and genes that cause poor lamb survival also result in good maternal traits that positively affect lamb survival. The fact that the direct and maternal heritabilites are low and the direct-maternal genetic correlation is negative does not mean that selection for improved lamb survival is a total waste of time. Since the heritabilities are not zero and the genetic correlation is not -1.00, selection may still result in some genetic improvement, but the improvement in lamb survival is expected to be 22

slower than improvement in more heritable traits. Since lamb survival is a trait with large economic value, even small genetic improvements can have a large impact on flock profitability. There are examples of selection experiments for lamb rearing ability that have shown progress over time. High Efficiency (HE) and Low Efficiency (LE) lines of Merino sheep for lamb rearing ability were established in Australia in 1974 (Haughey, 1983). The HE line was established with females from ewes that had weaned at least one lamb in 3 or 4 years out of 4 years, and the LE line was established with females that had failed to wean all their lambs in 2, 3, or 4 years out of 4 years. All surviving ewe lambs in each line were retained. Rams utilized in each line were selected from the best dams in the HE line and from the poorest dams in the LE line. From 1980-1982, 6 to 8 years after establishment of the lines, the HE line had 20.2% and the LE line had 33.6% lamb mortality from birth to weaning. Two lines of Merino sheep have been divergently selected since 1986 in South Africa (Cloete et al. 2005 and 2009). Ram and ewe lamb replacements in the High line have been selected from ewes that have generally weaned more than 1 lamb per mating, and ram and ewe lamb replacements in the Low line have been selected from ewes that have generally weaned less than 1 lamb per mating. From 1998 to 2002, after 12 to 16 years of selection, 67% of lambs in the High line and 47% of lambs in the Low line were multiple-born so selection had an effect on litter size. However, even though the High line had a greater litter size, it also had a higher lamb survival to weaning than the Low line (80% lamb survival for the High line vs. 71% lamb survival for the Low line) (Cloete et al., 2005). It appears that selection for improved lamb survival can be effective, but the genetic improvement per year may be quite low. Lamb survival also has an upper limit of 100%. If a flock already has a relatively high lamb survival of 95% or higher, there would be little opportunity or need to select for increased lamb survival. However, if lamb survival is low (80% or lower) under reasonable levels of management, selection for improved lamb survival may be desirable. We currently do not have the necessary knowledge to recommend the most effective manner in which to select for improved lamb survival. A practical approach would appear to be selection of replacement ewe and ram lambs from dams that successfully rear their lambs to weaning. While this appears to be a very simple and workable selection criterion, there are questions on how to implement it for which we do not have good answers. For example, consider the following scenarios: 1. Ewe A gives birth to and raises a single lamb in each of four lambings at 1, 2, 3, and 4 years of age. Ewe B gives birth to and raises 1, 1, 2, and 2 lambs in four lambings at 1, 2, 3, and 4 years of age, respectively. Both ewes raised 100% of their lambs. Which ewe is most likely to be genetically superior for lamb survival. You don t know, but you would probably select Ewe B and her progeny because she was challenged with twin lambs and succeeded in raising them. 2. Ewe C gives birth to 2, 2, and 2 lambs and weans 1, 1, and 2 lambs at 1, 2, and 3 years of age, respectively, for a survival percentage of 67%. Ewe D gives birth to and raises 1, 1, and 2 lambs at 1, 2, and 3 years of age, respectively, for a survival percentage of 100%. 23

You would probably select Ewe D and her progeny. Ewe C was challenged with twin lambs in her first two years and failed to raise all of them. 3. Ewe E gives birth to and raises 2 lambs in her first lambing for a survival percentage of 100%. Ewe F gives birth to 2, 2, 2, and 2 lambs and weans 1, 2, 2, and 2 lambs at 1, 2, 3, and 4 years of age, respectively, for a survival percentage of 88%. I would probably choose Ewe F and her progeny even though she has a lower survival rate for her lambs. With a lowly heritable trait like lamb survival, more performance data on an individual greatly increases the accuracy of the estimated genetic value. Ewe F was challenged with twins 4 times and only failed once. However, a case could be made for Ewe E who succeeded in raising twins as a ewe lamb, which is a less common occurrence than raising twins as a 2, 3, or 4 year old ewe. The scenarios above indicate that the selection criterion cannot be simply the percentage of lambs born that survived to weaning or the total number of lambs that survived to weaning. Since most of the genetic progress in a flock comes from sire selection, a practical recommendation would be to select replacement rams from older ewes that have had a large proportion of multiple births and raised all or most of their lambs. For ewe replacement selection, a producer may wish to establish independent culling levels for lambing percentage (e.g. at least 1.7 lambs born per lambing) and lamb survival (e.g. at least 80% of the lambs born survived to weaning). Ewe lambs would only be considered for a replacement if their dam met both criteria. One or both of these criteria could be increased or relaxed if too many or not enough dams met the original criteria. However, it should be noted that some authors are very apprehensive about using lamb survival, defined as the proportion of lambs in a litter that survive, in sheep selection programs. Everett-Hincks and Cullen (2009) reported a very low heritability of 0.01 for proportion of lambs in a litter that survive from a large data set in New Zealand involving 24 flocks and 31,651 ewes. They concluded, This study showed that there is little to be gained from including litter survival in sheep selection programs because heritabilities and repeatabilities for the litter survival traits were very low. They suggested that proxies for maternal care at lambing time such as reproductive hormone levels may be better selection criteria. There is much research to be done to determine the best selection criteria in order to develop estimates of genetic value (Expected Progeny Differences, EPD) for lamb rearing ability. The National Sheep Improvement Program currently calculates an EPD for number of lambs weaned per ewe lambing that is the best estimate we currently have available for genetic merit for lamb rearing ability. However, selection on this EPD will also result in increased litter size. Many producers may already have high enough litter size and may wish to only improve lamb survival. Animal genomics holds real promise for identifying differences between animals in their DNA profiles that are related to direct genetic and maternal genetic effects for complex traits such as lamb survival. Selection based on a combination of performance data and a DNA test could improve the accuracy of selection. Mating Systems Inbreeding and Crossbreeding Inbreeding. Inbreeding is the mating of related males and females, and the progeny resulting from such a mating are inbred. Inbreeding is quantified by the inbreeding coefficient (Fx) which 24

can vary from 0 to 1. Table 3 presents the inbreeding coefficients of progeny resulting from different types of matings. Inbreeding generally results in a decrease in performance called inbreeding depression. Inbreeding depression occurs for virtually all production traits in sheep, but it is especially large for lamb survival. The average decrease in lamb survival from inbreeding estimated from over 5,400 lamb records from 6 studies from an old review (Lamberson and Thomas, 1984) was -2.8 lambs surviving out of 100 lambs born for each 0.01 increase in Fx. This suggests that lambs resulting from the matings of half-brothers to half-sisters (progeny with Fx =.125) would be expected to have approximately 35 fewer lambs survive out of 100 lambs born compared to lambs born from unrelated parents. Inbreeding is to be discouraged. Table 3. Minimum inbreeding coefficient (Fx) from different types of matings involving relatives. Mating type Minimum Fx of progeny Sire - Daughter.25 Son - Dam.25 Full sibs.25 Half sibs.125 Sire - Granddaughter.125 While most flocks avoid intentional inbreeding, it is impossible to avoid some inbreeding with purebreeding. All animals within a breed are somewhat related, and an estimate of an average inbreeding coefficient of at least 0.02 is to be expected in most breeds. Therefore, a lamb mortality rate among purebred lambs of approximately 6% might be expected just due to the negative effects of inbreeding. Crossbreeding. Crossbreeding is the mating of rams and ewes of different breeds or different breed combinations, and it results in hybrid vigor. Hybrid vigor is the increased performance of crossbred animals over the average performance of the purebreds that made up the cross. Individual hybrid vigor is the increased performance due to the individual being a crossbred, and maternal hybrid vigor is the increased performance of an individual due to its dam being a crossbred. Hybrid vigor is the recovery of performance lost from inbreeding depression in pure breeds. Inbreeding results in a large decrease in lamb survival, but crossbreeding results in the opposite effect a large increase in lamb survival. Individual and maternal hybrid vigor for lamb survival to weaning averaged from many studies is estimated to be 9.8% and 2.7%, respectively (Nitter, 1978; SID, 2002). This means that a sheep producer can expect about 10 more lambs surviving to weaning from 100 lambs born if the lambs are crossbred compared to being purebred. An additional 3 more lambs survive to weaning per 100 lambs born if the crossbred lambs are produced from crossbred dams compared to producing crossbred lambs from purebred dams. These potential increases in lamb survival from hybrid vigor cannot be ignored, and 25

virtually all commercial sheep producers should be producing crossbred lambs from crossbred ewes. An example of the amount of individual hybrid vigor obtained from crossing Targhee and Suffolk sheep is presented in Table 4. These data are from a study conducted at the Dixon Springs Agricultural Center (DSAC), University of Illinois using purebred rams and ewes from a flock of Targhee (ILT) and Suffolk (ILS) sheep resident at DSAC, a flock of Suffolk (NDS) sheep established from importations over 3 years from North Dakota State University, and a flock of Targhee (OHT) sheep established at DSAC from importations over 3 years from Ohio State University (Long et al., 1989). The data are from over 1,300 matings. Production of crossbred lambs from purebred ewes resulted in 3.88 kg (13.8%) more weight of lamb weaned per ewe mated than production of purebred lambs (Table 4). The major factor causing increased ewe productivity when crossbred lambs were produced was the increased survival rate of crossbred compared to purebred lambs (5.4 more lambs surviving to weaning per 100 lambs born or 6.8% advantage of crossbred lambs over purebred lambs). Table 4. Productivity of purebred Suffolk and Targhee ewes producing purebred or crossbred lambs and estimates of individual hybrid vigor. Ram Ewe Fertility, % Prolificacy, no. lambs/ewe lambing Lamb survival, % Lamb 90-d wt., kg Ewe productivity, kg ILS ILS 80.2 1.50 79.0 30.82 27.74 OHT OHT 92.8 1.43 77.2 27.33 27.16 NDS NDS 83.1 1.69 76.6 26.40 27.02 ILT ILT 90.7 1.63 81.5 25.75 30.65 Purebred ave. 86.7 1.56 78.6 27.58 28.14 ILS OHT 91.2 1.40 85.1 29.33 30.20 OHT ILS 86.7 1.63 87.6 28.78 34.55 NDS ILT 88.7 1.62 83.9 28.34 31.48 ILT NDS 82.4 1.81 79.3 26.93 31.86 Crossbred ave. 87.2 1.62 84.0 28.34 32.02 Hybrid vigor 0.5 0.06 5.4 0.76 3.88 % hybrid vigor 0.6 3.5 6.8 2.8 13.8 References Berger, Y. M. 1997. Lamb mortality and causes A nine year summary at the Spooner Agricultural Research Station. In: Proceedings of the 45 th Annual Spooner Sheep Day. Dept. of Animal Sciences, UW-Madison. p. 33-40. (http://www.ansci.wisc.edu/extensionnew%20copy/sheep/publications_and_proceedings/pdf/nutrition%20and%20health/lamb% 20mortality%20and%20causes.pdf). 26

Bunge, R., D. L. Thomas, T. G. Nash, and R. L. Fernando. 1993. Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: Effect of breed of service sire on lamb production of Suffolk and Targhee ewes. J. Anim. Sci. 71:321-325. Casas, E., B. A. Freking, and K. A. Leymaster. 2004. Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: II. Reproduction of F1 ewes in fall mating seasons. J. Anim. Sci. 82:1280-1289. Cloete, S. W. P., I. Misztal, and J. J. Olivier. 2009. Genetic parameters and trends for lamb survival and birth weight in a Merino flock divergently selected for multiple rearing ability. J. Anim. Sci. 87:2196-2208. Cloete, S. W. P., A. J. Scholtz, J. J. E. Cloete, and J. B. van Wyk. 2005. The ability of Merino ewes and lambs to reunite after separation, as affected by divergent selection for ewe multiple rearing capacity. Australian J. Exp. Agric. 45:1131-1137. Dwyer, C. M. 2008. Genetic and physiological determinants of maternal behavior and lamb survival: Implications for low-input sheep management. J. Anim. Sci. 86:E246-E258. Dwyer, C. M. and A. B. Lawrence. 2005. A review of the behavioural and physiological adaptations of hill and lowland breeds of sheep that favour lamb survival. Appl. Anim. Behavior Sci. 92:235-260. Dwyer, C. M., A. B. Lawrence, H. E. Brown, and G. Simm. 1996. Effect of ewe and lamb genotype on gestation length, lambing ease and neonatal behaviour of lambs. Reprod. Fertil. Dev. 8:1123-1129. Everett-Hincks, J. M. and N. G. Cullen. 2009. Genetic parameters for ewe rearing performance. J. Anim. Sci. 87:2753-2758. Everett-Hincks, J. M., N. Lopez-Villalobos, H. T. Blair, and K. J. Stafford. 2005. The effect of ewe maternal behaviour score on lamb and litter survival. Livestock Prod. Sci. 93:51-61. Fogarty, N. M. 1995. Genetic parameters for live weight, fat and muscle measurements, wool production and reproduction in sheep: a review. Anim. Breeed. Abstr. 63:101-143. Freking and Leymaster. 2004. Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: IV. Survival, growth, and carcass traits of F1 lambs. J. Anim. Sci. 82:3144-3153. Haughey, K. G. 1983. Selective breeding for rearing ability as an aid to improving lamb survival. Australian Vet. J. 60:361-363. Lamberson, W. R. and D. L. Thomas. 1984. Effects of inbreeding in sheep: A review. Anim. Breed. Abstr. 37:191-202. Leymaster, K. A. and T. G. Jenkins. 1993. Comparison of Texel- and Suffolk-sired crossbred lambs for survival, growth, and compositional traits. J. Anim. Sci. 71:859-869. Long, T. E., D. L. Thomas, R. L. Fernando, J. M. Lewis, U. S. Garrigus, and D. F. Waldron. 1989. Estimation of individual and maternal heterosis, repeatability and heritability for ewe productivity and its components in Suffolk and Targhee sheep. J. Anim. Sci. 67:1208-1217. NASS (National Agriculture Statistics Service). 2010a. Sheep and goat death loss. NASS, Agricultural Statistics Board, USDA. 18 pp. (http://usda.mannlib.cornell.edu/usda/current/sgdl/sgdl-05-27-2010.pdf). NASS (National Agriculture Statistics Service). 2010b. Sheep and goats. NASS, Agricultural Statistics Board, USDA. 7 pp. (http://usda.mannlib.cornell.edu/usda/nass/sheegoat//2010s/2010/sheegoat-07-23- 2010.pdf). Nitter, G. 1978. Breed utilization for meat production in sheep. Anim. Breed. Abstr. 46:131-143. 27

Safari, E. and N. M. Fogarty. Genetic parameters for sheep production traits: estimates from the literature. Tech. Bull. Vol. 49. NSW Agriculture, Orange, Australia. http://www.sheep.crc.org.au/articles.php3?rc=145. Safari, E., N. M. Fogarty, and A. R. Gilmour. 2005. A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livestock Prod. Sci. 92:271-289. SID Sheep Production Handbook. 2002. American Sheep Industry Association, Inc. Centennial, Colorado. Vol. 7, p. 22. Southey, B. R., S. L. Rodriguez-Zas, and K. A. Leymaster. 2001. Survival analysis of lamb mortality in a terminal sire composite population. J. Anim. Sci. 79:2298-2306. (http://jas.fass.org/cgi/reprint/79/9/2298). Thomas, D. L. 2010. Performance and utilization of Northern European short-tailed breeds of sheep and their crosses in North America: a review. Animal 4:1283-1296. Welsh, C. S., D. J. Garrick, R. M. Ens, and G. B. Nicoll. 2006. Threshold model analysis of lamb survivability of Romney sheep. New Zealand J. Agric. Res. 49:411-418. WASB (Wisconsin Agricultural Statistics Bulletin). 2010. Wisconsin Field Office, NASS, USDA. 64 pp. (http://www.nass.usda.gov/statistics_by_state/wisconsin/publications/annual_statistical_b ulletin/annbull_2010_final_web.pdf). 28

RAISING LAMBS FROM WEANING TO MARKET Claire Mikolayunas Small Ruminant Extension Specialist University of Wisconsin Madison, Wisconsin In a dairy sheep operation, income from the sale of meat lambs can account for 20-35% of gross income. With the recent increase in the price of lamb, the relative value of lamb sales on dairy sheep operations may be increasing. The majority of dairy sheep operations in the Midwest are removing lambs from dams within 48-72 hours after birth and lambs are reared artificially on milk or milk replacer. After weaning, lambs can be managed in a variety of ways to grow them to market weight. Creep Feeding In a dairy sheep production system, lambs are weaned earlier than in a commercial meat operation, increasing the need for superior nutrition and management in order to successfully transition lambs from milk replacer to a growing diet. Lambs must have access to a creep ration as early as possible (10 to 14 days). Weaned lambs are more efficient at utilizing energy from feed compared to feeding the ewe (or purchasing milk replacer) to then feed the lamb. The purpose of creep feed is to increase the energy intake, supporting growth. For lambs weighing less than 50 pounds, dietary crude protein should be 18-20%. For lambs greater than 50 pounds, dietary crude protein can be 14-16%. Creep rations do not need to be complex a mixture of 90% corn and 10% soybean meal can be an effective ration. In a commercial production system, feeding creep to nursing lambs is common when production emphasizes multiple births, rapid lamb growth, or if environmental conditions restrict ewe nutrition (range or low quality pastures). In pasture situation, feeding creep to lambs may only be profitable when pasture quality is low or declining. For lambs raised as singles, there is little benefit to providing creep feed. For lambs raised as twins or triplets, daily gains may be 0.2#/d higher if supplemented with creep feed. Post-Weaning In some dairy production systems, lambs can be weaned as early as 21 to 28 days, reducing rearing costs by reducing lamb milk replacer expenses. If started on creep early, lambs will begin to consume a significant amount of creep feed at 3-4 weeks of age. Data from 451 lambs recorded during the 2011 Spooner Agricultural Research Station lambing season indicated an average birth weight of 11.9 pounds and an average weaning weight of 28.1 pounds (2.4 times birth weight) at 30.8 days of age. While there are no statistics associated with this data, Graph 1 displays the difference in weaning weight and weaning age of lambs from the 2011 Spooner flock. The Katahdin crossed lambs were weaned at a lower weights and older ages, but these lambs also began with 1.9 to 3.1 less pounds of body weight at birth. 29

Graph 1. Weaning weight and weaning age of lambs based on sire and dam genetics. Number of animals in each breed and average birth weights are as follows: Dairy*Dairy n=130, 11.6 lbs; Dairy*Dorset n=17, 11.3 lbs; Dairy *EF n=171, 12.5 lbs; Dairy*Hamp n=90, 12.6 lbs; Kat Cross*Lac n=4, 9.43 lbs. Growth Pattern In a growing animal, the deposition of bone, muscle, and fat occurs at different rates (Graph 2). This growth pattern is regulated by a complex interaction of regulating factors and changing requirements for tissue growth. As an animal reaches physiological maturity, the rate of fat deposition increases and the percentage of body fat is greater. Maturity can be specified in relation to mature body size (Freer and Dove, 2002). In comparing two animals of a similar size, the one with a larger mature body weight will be leaner than an animal with a smaller mature body weight. The goal for growing and finishing lambs is to reach the optimum relationship of muscle and fat relative to the frame size of the animal. If an animal is allowed to grow beyond the optimum finished weight, they will experience decreased rates of gain, decreased feed efficiency, and undesirable (overly fat) carcasses. Graph 2 (Image Courtesy of Texas A&M) 30

Growing Diets Less mature animals have the potential for higher rates of protein accumulation and higher proportion of their energy stored as protein, compared to being stored as fat. Fat gain is related to amount of energy in excess of maintenance and protein gain costs. The rate of gain of fat also increases with stage of maturity, up to 70% mature (Freer and Dove, 2002). The growing phase may be considered as the period from 40 to 80 pounds. The nutritional requirements for young, growing animals is primarily for energy (Table 1). In both moderate and rapidly growing lambs, energy requirements increase with increasing body weight. However, since dry matter intake (DMI) increases, the energy density of the diet (or % TDN) decreases. Protein requirement increases as daily gain increases, reaching a maximum, then plateau and even decrease. The weight at which protein requirements plateau is determined by mature body weight. Feeding excess protein is wasteful, as it may be metabolized into energy and stored as fat. Lambs with moderate to rapid growth potential will gain 0.5 to 0.8 pounds per day, some achieving over 1 pound per day. In order to accomplish these gains, lamb diets should contain 75 to 80% TDN and 14 to 17% CP. Intake levels should reach 3 to 5 % of body weight in larger and smaller lambs, respectively. Table 1. Nutrient Requirements of Growing Lambs (NRC, 2007) Production stage Body Wt (lb) Intake (lb/day) Lbs. TDN % TDN Lbs. CP % CP 44 2.2 1.8 82 0.37 17 Moderate Growth 66 2.9 2.2 76 0.42 14 Potential 88 3.3 2.7 79 0.44 13 110 3.3 2.6 79 0.40 12 High Growth Potential 4-7 Month Lambs 44 2.6 2.0 77 0.45 17 66 3.1 2.4 77 0.48 15 88 3.3 2.5 76 0.51 15 110 3.7 2.8 76 0.53 14 66 2.9 2.1 72 0.42 14 88 3.5 2.7 77 0.41 12 110 3.5 2.7 77 0.35 10 Based on these nutrient requirements, Table 2 indicates some example creep and growing rations. There are many rations available for growing lambs, these are simply provided as examples. The main point is the high energy content (TDN%) and the lower CP requirement as lambs approach market weights. Table 2. Example Growing Ration To 70 lb. 70 to 90 lb. 90 lb to Market (%) (%) (%) Ground Corn 49 59 69 Chopped Grass Hay 33 23 13 Soybean meal 10.5 10.5 10.5 Molasses 5 5 5 31

Trace Min. Salt + Se 1 1 1 Dicalcium phosphate 1 1 1 Ammonium Chloride 0.5 0.5 0.5 TDN (% ) 66.8 69.5 72.1 CP (%) 11.5 11.4 11.3 (Source: ASI, 2002; NRC, 2007) Other grains can be fed in place of corn in a growing and finishing ration. Grains may be substituted as indicated in Table 3. Alternative sources of energy, such as food processing waste, can be used in rations but gains will not equal those of grains. Including roughage in the diet can increase dietary energy (silage and grass or grass/legume haylage), increase dietary protein (legume forages) or improve rumen function. Table 4 indicates the relative cost of using feeds other than corn as sources of energy. Table 3. Relative Feeding Value of Grains (ASI, 2002) Lb Required to Feedstuff Feed Value Relative to Corn Equal 1 Lb. Corn Notes Shelled Corn 100 - Sorghum 95 1.05 Barley 90 1.10 Oats 80 1.25 Wheat 105 0.95 Feed <50% diet grain Ground ear corn 88 1.14 Mix 95% ear corn + liq. mol. Liquid Molasses 70 1.43 Not >5% complete diet Table 4. Relative Dollar Value of Shelled Corn ($/100 lb) and Other Energy Sources Shelled Corn, $/100 lb. Adjustment $6.25 ($3.50/bu) $12.00 ($6.72/bu) factor Barley 0.90 5.63 4.83 Oats 0.80 5.00 4.29 Wheat 1.05 6.56 5.63 Ear Corn 0.88 5.50 4.72 Sorghum 0.95 5.94 5.09 Ground Ear Corn 0.88 5.49 4.71 Liquid Molasses 0.70 4.37 3.75 ($/ton) ($/ton) Corn Silage 7.40 46.25 88.80 Hay 11.60 72.50 62.18 Alfalfa 11.00 68.75 58.96 Clover 11.20 70.00 60.03 Grass-Legume 10.80 67.50 57.89 Orchardgrass 7.60 47.50 40.74 Timothy 5.60 35.00 30.02 32

Bluegrass 5.16 32.24 27.65 The physical form of the diet should be uniform to reduce sorting, not to increase digestibility. Creep rations are most palatable when fed in meal form, such as crimped, cracked, rolled or pelleted feeds. Ground grain can produce dusty feeds, reducing intake and increasing the risk of respiratory disorders. If hay is to be mixed with concentrates, chopping or coarsely grinding the forage will encourage uniform consumption and reduce wastage. If a large amount of forage is included in the diet, pelleting will increase intake. Finishing Diets The thickness of fat covering the ribeye muscle is generally used as an indicator of lamb carcass fatness. While fat thickness can range from 0.05 to 0.50 inches, the industry average is 0.30 inches. The desired range is 0.15 to 0.25 inches. Less fat contributes to carcass shrinkage, discoloration, and a reduction in meat quality. Excess fat contributes to lower yield of closely trimmed, wholesale and retail cuts. The frame size of a lamb, defined as the lamb s skeletal height and length in relation to age, will determine the weight at which the animal is ready for slaughter. Traditional slaughter weights of lambs in the United States are approximately 60% of the physiological mature size of the dam (Snowder et al., 1994). Table 5 below indicates the approximate relationship between live weight and fat thickness for small, medium and large-framed lambs: Table 5. Live weight and fat thickness for various mature frame sizes. Frame Size Slaughter Weight (lbs) Small (200 lb mature ram) Medium (250 lb mature ram) Large (300 lb mature ram) 90 0.15 0.10 0.05 100 0.20 0.15 0.10 110 0.25 0.20 0.15 120 0.30 0.25 0.20 130 0.35 0.30 0.25 140 0.40 0.35 0.30 (from National Lamb Feeders 409 Coursebook) In order to reach the desired fat thickness, most lambs in the United State are on finishing diets for a minimum of 30 days. As seen in Table 1, the energy requirement is 73-78% TDN and 10-14% CP, based on body size. When transitioning diets from a grower to a finisher diet, transition over 14 days period. Remember that you are changing the ecology of microorganisms in the rumen, a process which take a gradual transition. If lambs are fed at a level of 3 to 4% of their body weight, they should gain 0.6 to 1.0 pounds per day (Neary, 1998). Pasture Finishing Lambs may be finished on high forage diets, such as pasture, but lambs will typically have lower rates of gain and leaner carcasses. Slower rates of gain may not be undesirable if they are cost 33

effective. Throughout the United States, lambs are finished on fall crop residues, such as wheat, pea stubble, or corn stubble. Lambs may also be finished on cultivated crops, such as brassicas. Lambs finished on pasture must have experience grazing with ewes, or intake and performance will be depressed. Lambs should be adjusted to this management system over 2-3 weeks, grazing high quality pasture for short periods of time. Similar to ewes turned out onto fresh pasture, lambs should be turned out with a full rumen, as they can suffer from enterotoxemia from lush forage. Grazing time can be gradually increased over 2-3 weeks. Pasture-raised lambs may also benefit from access to creep feed prior to weaning. In addition to pasture-only diets, lamb growth may be maximized if lambs are also supplemented with concentrates at the following levels: 50-60 lb = 0.5 lb/hd/day 60-75 lb = 1.0 lb/hd/day 75-90 lb = 2.0 lb/hd/day > 90 lb = 3.0 to 4.0 lb/hd/day Based on the target market, lambs may have access to this supplement during the last 30-40 days of growth. Lambs on cool season grasses or legumes may only need supplementation of energy. However, when grazing moderate forage, 10% of the supplement can be protein source. Expected gains from pasture-grown lambs will depend on the genetic potential of the animal. In an evaluation of supplementation on pasture in lambs grown from 70 to 110 pounds, average daily gains for pasture-only lambs were 0.34 lb/day, gains for pasture plus 2.2 lb of 13% CP supplementation were 0.58 lb/day and gains in drylot (intake of 4.55 lb/day) were 0.59 lb/day. Therefore, the feed:gain ratio of lambs supplemented on pasture was higher (3.79) compared to feedlot lambs (7.71). Lambs can also be finished on pasture without supplemental grain. Borton et al. (2005) evaluated the effect of finishing Targhee x Hampshire lambs to weights of 115 or 170 on either confinement diets or grazing ryegrass pastures. In comparing lambs reared to 115 pounds, average daily gain (ADG; lb/d) of forage and confinement lambs from weaning to slaughter were 0.33 and 0.33, respectively. Therefore, days on feed were 184 days for grazing lambs and 82 days for confinement lambs. McClure et al. (1994) evaluated the effect of finishing lambs on rotationally grazed pastures (orchardgrass, ryegrass or alfalfa) and confinement diets. Average daily gain of lambs for the drylot, alfalfa, ryegrass and orchardgrass grass treatments were 0.57, 0.49, 0.28, and 0.28 lb/d respectively. Lambs grazed on grasses had smaller carcasses with less muscle, fat and bone. Although carcasses of lambs grazed on alfalfa were lighter, they had the same muscle mass as concentrate-fed lambs and less fat and more desirable yield grades than concentrate fed lambs. McClure et al (1995) also evaluated the effect of grazing and finishing on drylot on Targhee x Hampshire lambs. In this trial, lambs were assigned to the following post-weaning treatment: all concentrate in drylot, grazing alfalfa, grazing ryegrass, grazing ryegrass for 62 days then drylot, and grazing ryegrass for 62 days then alfalfa. Average daily gain for the treatments were as follows: Drylot Alfalfa Ryegrass Rye + drylot Rye + Alf 34

ADG (lb/day) 0.77 a 0.49 b 0.31 d 0.41 bc 0.33 cd Days on test 58 a 77 b 178 e 133 c 154 d Carcass fat was lowest on alfalfa treatment. Lambs backgrounded on ryegrass had high lean:fat tissue gain and a higher percentage of lean in their carcass compared to drylot lambs. In a recent trial, Jacques et al. (2011) evaluated the effect of four finishing diets on growth rates of weaned Dorset lambs: ad libitum concentrates, restricted concentrates, zero grazing (forage brought to the lambs) and grazing. All concentrate-fed lambs had access to dry hay. Lambs were weaned at 52 pounds and slaughtered when they reached 105 pounds. Average daily gains and feed efficienecy are presented in Table 6. Overall, forage-based diets may prevent excessive carcass fat in heavy lambs while producing similar muscle development, resulting in a leaner product for consumers. Table 6. Concentrates Restr. Conc Zero Graze Grazing ADG (lb/d) 0.99 c 0.76 b 0.59 a 0.65 a Days on feed 105 a 122 b 146 c 145 c Feed Efficiency (% or Gain:DMI) 0.32 c 0.25 b 0.18 a 0.20 ab Pasture versus Drylot While pastured animal have a slower rate of gain, rising costs for grain may make pasturedraised animal more economical. In an update to the economic evaluation of Berger (1995), here is s rough economic evaluation of raising drylot versus pasture reared lambs. Basic Assumptions: - Weaning at an average of 50 pounds and finishing to 110 pounds. - Costs only to rear lambs, not to include ewe management. - Lambing in spring to utilize forages for lamb growth - All lambs raised to market weight, none sold as feeders. - Lambing on April 1, weaned at 60 days on June 1. For confinement lambs: - ADG of 0.77 lb/d (average of above trials 0.99, 0,77 and 0.57 lb/d) - Total of 78 days to market weight of 110 pounds. - Market date of August 18, $ 132/cwt = Income of $145.20 - Feed efficiency of 0.25. To gain 60 pounds, intake of 240 pounds of grain. - Grain cost of $431/ ton (April, 2011) or $0.2155/ pound. - Total grain cost of $51.72 - Income over feed = $93.48 For pasture lambs: - ADG of 0.55 (average of above trials 0.65, 0.50, 0.49) - Total of 109 days to market 35

- Market date of September 18, $135/cwt = Income of $148.50 - Pasture cost: Iowa State University analysis of cost per acre for pasture (http://www2.econ.iastate.edu/faculty/duffy/pages/pastureandhay.pdf) indicated an annual cost of $110 per acre. At a stocking rate of 10 lambs per acre, this is a cost of $11 per lamb. - Income over feed = $137.50 Terminal Sires As any geneticist will tell you, production is a result of the combination of genotype and the environment. Producers must not overlook the contribution of genetics to achieve desirable growth rates and carcass characteristics. As the market for milk and dairy genetics changes (possibly decreasing) and the market demand for lamb increases, producers may choose to breed more of their dairy ewes to terminal sires. Graph 3 indicates growth rates for lambs sired by different breeds in the 2011 Spooner lamb crop. Terminal sires contribute large, lean and efficient growth to lambs. Graph 3. Growth rates of Spooner lambs from 53-64 days post-weaning. Number of animals in each breed are as follows: Dairy*Dairy n=55, Dairy*Dorset n=3, Dairy *EF n=72, Dairy*Hamp n=88, Kat Cross*Lac n=9 Rearing Rams or Wethers In a trial evaluating the effect of castration on average daily gain, Arnold and Meyer (1988) reported that feed efficiency (pounds of gain per pound of feed) was 19% greater in rams compared to wethers. However, ADG was not different between ewes and wethers or between wethers and rams when grown to 115 pounds. When comparing animals sired by white-faced and black-faced rams, black-faced lambs were 5% more efficient at utilizing feed compared to 36