Food intake and. growth of German 1 shepherd puppies G. E. Schroeder* and G. A. Smith Department of Animal and Wildlife Sciences, University of Pretoria, Pretoria. 0001, Republic of South Africa Iournal of Small Animal Practice (1994) 35, 587-591 ABSTRACT The nutritional programme followed during the growth and development of the German shepherd puppy may have a significant influence on the dog s value as a potential working or breeding animal. Limited research has been undertaken on the nutrition of the dog from birth until four to five weeks of age. The objective of this study was to establish a baseline in terms of food intake and growth, which can be used in a nutritional and managerial programme in a commercial breeding unit. The food intake and growth of 10 German shepherd dog litters, with an average of six puppies per litter, were monitored from birth to 12 weeks of age. Both food intake and growth was described by regression equations. A commercially available diet was fed throughout the study. Performance criteria, namely food intake and bodyweight, were established which could be used in a commercial German shepherd dog breeding unit. INTRODUCTION The objective of a nutrition programme is to ensure that the required growth and development of an animal is obtained while maintaining good health, activity and longevity (Holme 1979). Though a dog may have the genetic potential to grow at a specific rate, extrinsic factors such as nutrition, environment and health care can influence its performance (Meyer 1983). Studies of body composition in the dog have demonstrated that skeletal development is at a maximum (Sokolowski 1982) during the first six months of life and considering that the growing puppy may double its birthweight within seven to nine days after birth (Mundt and others 1981), nutrition can have a significant effect on its growth rate and body size. When developing an appropriate nutritional programme for growing puppies, it is essential to establish measurable criteria against which the performance of the puppies can be monitored during the growth period; this can be divided into three phases: 0 Phase 1. That period during which the puppy is completely dependent on the bitch s milk, and therefore its growth is, to a large extent, determined by the performance of the bitch. This phase ranged from birth to three weeks of age in this specific breeding unit. 0 Phase 2. That period during which the pup, though still suckling, starts to consume soft balanced diets, a situation which continues from three weeks until the end of weaning at six weeks of age. 0 Phase 3. That period representing the growth and development from weaning at six weeks of age until 12 weeks of age, from which stage the dogs are exposed to an intensive training or working programme. In this study, the influence of nutrition on the growth of the puppies was monitored up to the end of the third phase, the objective being to establish realistic criteria against which to gauge the food intake and growth of a litter in a commercial security dog breeding unit. MATERIALS ~ ~ AND ~ METHODS G. E. Schroeder s present address is Agricultural Research Council, Private Bag X2, Irene, 1675, Republic of South Africa Animals Ten German shepherd dog litters, ranging from four to nine pups, with an average of six per litter, were used in this study. From three weeks of age the puppies were handled daily and were
G. E. SCHROEDER AND G. A. SMITH placed in a pen on the lawn for an hour while the kennels were washed; this period away from the bitch gradually increased as the pups grew older, up to four hours per day at six weeks of age. The puppies were fed and given water inside the pen when they remained outside for longer than an hour. Socialising started at four weeks of age when the puppies were exposed to contact with both strangers and new environments. They were completely weaned at six weeks of age when the dam was removed. This was the practice in the unit and was also recommended by Bebiak and others (1987). At the ages of eight and 11 weeks their reaction to strangers and moving objects was evaluated by specially designed tests. The litters were housed in whelping kennels until they were 12 weeks of age. These kennels measured 2 X 4.75 m and had a heated whelping area of 1.5 X 1.5 m. The following temperatures were recommended by Christiansen (1984) and were maintained in the breeding unit: 0 First week: 29 to 32 C 0 Second week: 26 to 29 C 0 Third week: 23 to 26 C 0 Fourth week and onwards until 12 weeks of age: 23 C Maintaining these temperatures in the whelping area is essential in order to prevent losses due to very low temperatures, which could have serious economic consequences in a commercial breeding unit. The litters were vaccinated against canine parvovirus (CPV) (First Dose; Norden Laboratories) at four and six weeks of age. At eight weeks they were vaccinated against distemper, adenovirus types 1 and 2, measles and parainfluenza (Vanguard DA,MP + CPV; SmithKline Beecham Animal Health). At 12 weeks of age they were vaccinated against distemper, adenovirus types 1 and 2 and parainfluenza (Vanguard DA,P + CPV; Table 1. Composition of test diet I Component 4215 kcal G us 1000 kcal GEkg Protein 30.0 % 7.12 % Moisture 10.0 % 2.37 % Fat 8.0 % 1.90 % Fibre 5.0 % 1.19 % Calcium 1.2 % 0.28 % Phosphorus 0.9 % 0.21 % Ca:P 1.33: 1 1.33~1 Linoleic acid 2.0 % 0.83 % Digestible carbohydrates 36.02 % 8.55 % Vitamin A 6000 iulkg 1424 iu Vitamin D, 600 iu/kg 142.4 iu Vitamin E 60 iu/kg 14.24 iu GE 17.64 MJ GE/kg or 4215 kcal GE/kg Ca:P Calcium to phosphorus ratio SmithKline Beecham Animal Health). An anthelmintic, namely pyrantel pamoate (Nemex; Pfizer) was used at two, six and 10 weeks of age to remove roundworm. At four, eight and 12 weeks of age the litters were dewormed with fenbendazole (Panacur 10%; Hoechst) to remove roundworm and hookworm. The weighing of the puppies took place on a weekly basis from 24 hours after birth until the dogs were 12 weeks old. Diets A balanced diet with a basic composition as shown in Table 1 was given to the puppies on an ad libitum basis from 21 days of age (Alexander and Wood 1987). The diet was presented in a creep feeder thus preventing the bitch from eating the puppies food. Apart from this diet, which was given in a dry form, the palatability and intake were enhanced by also giving the same diet in a moistened and ad libitum form to the puppies three times a day. The ratio between feed and water was 1:1. This approach was in line with the recommendations of Baker (1984) and Bebiak and others (1987). The additional wet feed was presented to the pups at 08.00 hours, 14.00 hours and 18.00 hours each day until they were eight weeks old, after which the moistened feed was supplied only twice a day at 08.00 hours and 18.00 hours each day up to the age of 12 weeks, as recommended by Baker (1984). In order to evaluate the performance criteria of the litters, the following were recorded: 0 Litter size at whelping 0 Average bodyweight of the litter at birth 0 Average weekly food intake of the litter from three weeks until 12 weeks of age 0 Average weekly bodyweight changes in the litters from birth until 12 weeks of age RESULTS The average weekly bodyweights of the litter, their average feed intake as well as their average daily weight gain are presented in Table 2. Regression analysis was used to determine the regression equations for feed intake and mass changes, using a computer program (SAS 1985). The regression of the food intake of the puppies over time is shown in Fig 1. The regression of the puppy weight over time is shown in Fig 2. The innermost lines in Fig 1 represent the 95 per cent confidence limits and the outermost lines the 99 per cent prediction level of the regression line. The regression line, as described in equation 1, has an R value of 043072. y= axb..... (equation 1)
I O. C ' ' ' ' I ' ' ' ' ' ' ' ' Age ' ' ' (weeks) l ' ' ' ' ' ' ' 'Ii' ' ' ' ' ' /z FIG 1. Regression of the average food intake over time, showing the innermost confidence limits and outermost prediction levels 0 I 2 3 4 5 6 7 8 9 1 0 1 1,, Age (wecks) FIG 2. Regression of the average litter bodyweight over time, showing the innermost confidence limits and outermost prediction levels where y = intake of food (kg) a = 0.002135*, b = 2-4319 and x = age in weeks (*Intercept = In a). The growth of the puppies is shown in Fig 2, with the regression line, found to be the best fit, described by equation 2. where y= ela + bxl..... (equation 2) y = mass (kg), a = -0.2966, b = 0.2045 and x = age in weeks This equation describes the growth, with an RZ value of 0.9115. The innermost lines in Fig 2 represent the 95 per cent confidence limits and the outermost lines the 99 per cent prediction level of the regression line. DISCUSSION The composition of the diet (Table 1) indicates that this meets the minimum nutrient requirements for growing dogs (NRC 1985). Kirk and Bistner (1986) reported satisfactory growth of puppies with diets containing between 12.00 and 14.27 MJ/kg, which is 3.37 to 5.64 MJ/kg lower than the energy level of the diet used in this study. As far as the minimum level of protein in the diet is concerned, it is evident that the level in this diet exceeds the minimum requirement of between 25 and 27 per cent (Murphy 1983, Kirk and Bistner 1986). Not only is the level of protein important but also the ratio between the essential amino acids (NRC 1985). Due to the fact that the puppy cannot utilise fibre, the level in the diet should be restricted to between 5 and 8 per cent (Kirk and Bistner 1986, Kronfeld 1986). A level of approximately 5 per cent fibre was used in this diet and may be beneficial to the animal due to the effect of the fibre per se within the alimentary canal, namely by reducing the gastrointestinal transit time and thus increasing nutrient availability slightly. The 8 per cent fat level in the diet is on a par with the recommended level of between 5 and 8 per cent (Kirk and Bistner 1986, Kronfeld 1986). Although higher quantities may be warranted to achieve diets with higher energy levels for dogs in colder climates, caution should be exercised as higher fat levels may exhibit nutrient deficiencies such as protein, minerals and vitamins (NRC 1985) and could decrease the feed intake of puppies, especially when high temperatures prevail. The calcium and phosphorus (Ca:P) ratio in the diet of the growing puppy is very important as it will affect the bone formation of the dog. The diet used in the study had a Ca:P ratio of 1.33:l which is above the minimum ratio of 1.2:1 (NRC 1985) and is comparable with the recommended ratio of between 1.1 and 1.5:1, as suggested by various workers (Sokolowski 1982, Switzer and others 1986, Hand and others 1987). When a complete balanced diet is used, such as the diet in this study, no additional supplementation in the form of vitamins, minerals, meat or any other additives should be needed. Consequently, no supplementation was given to the puppies which is in agreement with the findings of Bebiak and others (1987). The intake of sufficient nutrients by the puppies is a prerequisite for optimal growth. The average food intake per puppy over the period from four to 12 weeks of age is depicted in Fig 1 as a regression of food intake over time. It is evident that food intake increases exponentially with age. A steady increase in food intake from the fourth week is observed, which is the start of solid food consumption. The average daily food intake of an eight-weekold German shepherd litter, should, according to equation 1 and Fig 1, be as follows: => y= axb..... (equation 1) y = 0.002135 X 8'2-43191 y = 0.002135 X 157.12 y = 0.336 kg foodlday 589
G. E. SCHROEDER AND G. A. SMITH The average daily food intake of the litter should be 0.336 kg/day. By making use of the confidence limits in Fig 1, 95 per cent of the litter should have an intake between 0.280 and 0.375 kg/day, but by using the prediction level, 99 per cent of the litter should have an intake of between 0.148 and 0.745 kg/day. This can now be used as a guideline for food intake in a nutritional programme for German shepherd puppies in a commercial breeding unit. Food intake represents the total intake by the pups of the dry food presented on an ad libitum basis, plus the amount which was moistened (ie, excluding the water) of the same diet. It must be kept in mind that up to six weeks of age, solid feed as well as milk from the dam is consumed by the pups. Holme (1979) observed that as the puppies interest in solid food increases, after 21 days, the demand for milk decreases, with a consequently lower food intake by the bitch. After the third or fourth week of lactation, the dam s milk production will decline while she becomes increasingly reluctant to nurse her puppies, an observation made by Bebiak and others (1987). As the puppies become more active they suckle less frequently (Christiansen 1984) and nutrients must therefore be supplied by means of a palatable balanced diet to ensure optimal intake. The feed intake of 31 g/kg live bodyweight, obtained in week 4 of this study, was equivalent to the 20 to 30 g/kg intake reported by Meyer (1983) for puppies born from bitches weighing between 32 and 35 kg, which includes German shepherd dogs. Clean, fresh drinking water is essential for the bitch and puppies and was at all times available on an ad libitum basis. Any restriction in availability of water would have a severe effect on food intake. In this study, water was supplied by means of automatic drinkers, except when the puppies were outside, when a water bowl was used. Another aspect which may influence food intake by the pups is the compaction of the food due to puppy activity. This problem was solved by restirring the food frequently. The extent to which these factors influenced performance are shown in Table 2. The performance of puppies during the first weeks of their lives can, to a large extent, be determined by their birthweight. In this study, the average birthweight was 0-520 kg which was higher than the value of 0.447 kg for German shepherd puppies reported by Schroeder (1991) and 0.443 kg reported by Meyer (1983), for puppies born from bitches weighing between 32 and 35 kg, which includes German shepherd dogs. The bitches used in the present study were between one and two years old and weighed between 17 and 36 kg. The fact that they were relatively young may have contributed to the smaller average litter size of six (between four Table 2. Food intake, average daily weight gain and average weight of the puppies, between birth and 12 weeks of age (standard deviations are in brackets) Age Average daily Average daily Average weight (weeks) food intake weight gain (kg) (kg) (kg) 0 1 2 3 4 5 6 7 8 9 10 11 12-0.065 ( f 0.02) 0.1 11 ( f 0.07) 0.165 (to.07) 0.299 ( t 0.1 4) 0.488 (k0.12) 0.555 (ko.19) 0.584 ( t 0.17) 0.693 ( f 0.1 5) 0.733 (ko.10), - 0.049 ( f 0.02) 0.056 ( t 0.02) 0.067 ( t 0.03) 0.052 ( f 0.05) 0.042 ( f 0.04) 0.045 ( k 0.031 0.068 (? 0.05) 0.106 ( f 0.06) 0.113(t0.04) 0.1 53 ( t 0.06) 0.141 (fo.09) 0.135 (fo.10) 0.520 (? 0.1 1) 0.864 (k0.17) 1.255 (fo.19) 1.721 (f0.29) 2.083 ( t 0.61 ) 2.376 ( f 0.64) 2.693 ( 0.60) 3.171 (f0.83) 3.916 ( t 0.96) 4.708 (5 1.00) 5.782 ( t 0.80) 6.768 ( f 1.24) 7.718 (f 1.02) and nine), compared to an average of eight reported by Christiansen (1984). The smaller litter size could have contributed to the fact that the puppies were heavier at birth. When birthweight of individual pups was expressed as a percentage of the bitch s mass, an average value of 1.97 per cent was recorded in this study, compared to a value of 2.16? 0.65 per cent reported by Meyer and others (1985) and 1.65 per cent reported by Schroeder (1991), indicating that the bitches were at par with previous studies. The smaller litter size is reflected in the fact that when the average litter weight at birth is expressed as a percentage of the bitch s weight, a value of only 7.89 per cent is recorded, compared to a value of 13.5 per cent reported for large dogs (which includes German shepherd dogs) by Meyer and others (1985). A large dog is generally defined as a dog with an average bodyweight of 35 kg. The dogs used in this study were slightly lighter than 35 kg. The size of the dog per se would, however, have a pronounced effect on this percentage, a value between 7.0 and 25.0 per cent would accommodate all breeds of dogs (Kienzle and others 1985). Considering that the puppies doubled their birth mass within nine days, an observation which is in line with the findings of Mundt and others (1981), it is evident that the bitches supplied sufficient quantities of milk to their young. The average bodyweight of an eight-week-old German shepherd dog litter, when using equation 2 and Fig 2, should weigh as follows: => y = e[o+bx). = e[-o.zwi + 0.2045 (1311.... (equation 2) Y = y = 3.817 kg The average bodyweight of the litter should be 3.817 kg. By using the confidence limits in Fig 2, 5 90
95 per cent of the litter should weigh between 3-60 and 4-00 kg, but by using the prediction level, 99 per cent of the litter should weigh between 2-35 and 6.45 kg. This can now also be used as a baseline for bodyweight in a management programme of the puppies in a commercial breeding unit. It is important that the puppy should grow actively during the first 12 weeks of its life. The results in Table 2 indicate that this was indeed the case in this study. Growth was, however, slightly suppressed during the period from three to seven weeks of age, which included the period of weaning. However, after this period, an accelerated average daily weight gain was obtained. An average three-week weight of 2.10 kg and an average weaning weight of 3.25 kg was achieved, which compares well with the 1.688 kg and 3.063 kg obtained in a study of German shepherd puppies by Schroeder (1991). It is of interest that there is a statistically insignificant correlation between the average birthweight and the average weight of the puppies at six (r = 0.33) and 12 (r = 0.31) weeks of age. Though a puppy with a low birthweight may be susceptible to domination and slower growth, it was observed that the growth of the puppies was to a large degree dependent on the management, care and nutritional status after birth rather than birth mass per se. CONCLUSION Satisfactory growth of the pups was obtained with the present diet and a response area was described (the confidence limits and prediction level) which can be of value in the day to day monitoring of a management and nutritional programme for rearing puppies in a commercial breeding unit. The question however arises as to whether satisfactory growth of the puppies could be maintained with less nutrient (protein and energy) dense diets, which could influence the subsequent working ability and the longevity of the dogs. ACKNOWLEDGEMENTS The authors wish to thank the management of Roodeplaat Breeding Enterprises for financing this study and the availability of the dogs and facilities. The South African Medical Services is thanked for the opportunity they created for G. Schroeder to complete this study. Veterinary nurses Ron61 Cronj6, Karen Trimm, Michelle Matthee and Anita Viviers are thanked for their valuable assistance in the management and care of the dogs and Klaas-Jan Leeuw for his assistance with the statistical analyses. REFERENCES ALEXANDER, J. E. & WOOD, L. L. H. (1987) Growth studies in labrador retrievers fed a caloric-dense diet. Time restricted versus free-choice feeding. Canine Practice 14, 41-47 BAKER, D. H. (1984) Equalized versus ad libitum feeding. Nutrition Reviews 42, 269-273 BEBIAK, D. M., LAWLER, D. F. & RENTZEL, L. F. (1987) Nutrition and management of the dog. Journal of Small Animal Practice 17, 505-533 CHRISTIANSEN, I. J. (1984) In: Reproduction in the Dog and Cat. 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