Energy intake, growth rate and body composition of young Labrador Retrievers and Miniature Schnauzers fed different dietary levels of vitamin A

Abstract

Research in rodents has shown that dietary vitamin A reduces body fat by enhancing fat mobilisation and energy utilisation; however, their effects in growing dogs remain unclear. In the present study, we evaluated the development of body weight and body composition and compared observed energy intake with predicted energy intake in forty-nine puppies from two breeds (twenty-four Labrador Retriever (LAB) and twenty-five Miniature Schnauzer (MS)). A total of four different diets with increasing vitamin A content between 5·24 and 104·80 mmol retinol (5000-100 000 IU vitamin A)/4184 kJ (1000 kcal) metabolisable energy were fed from the age of 8 weeks up to 52 (MS) and 78 weeks (LAB). The daily energy intake was recorded throughout the experimental period. The body condition score was evaluated weekly using a seven-category system, and food allowances were adjusted to maintain optimal body condition. Body composition was assessed at the age of 26 and 52 weeks for both breeds and at the age of 78 weeks for the LAB breed only using dual-energy X-ray absorptiometry. The growth curves of the dogs followed a breed-specific pattern. However, data on energy intake showed considerable variability between the two breeds as well as when compared with predicted energy intake. In conclusion, the data show that energy intakes of puppies particularly during early growth are highly variable; however, the growth pattern and body composition of the LAB and MS breeds are not affected by the intake of vitamin A at levels up to 104·80 mmol retinol (100 000 IU vitamin A)/4184 kJ (1000 kcal).

Energy requirements for growth in the Yorkshire terrier

“…When the energy requirements of the Yorkshire terriers, Labrador retrievers and miniature Schnauzers were compared, breed-specific patterns were observed. In agreement with data previously reported for miniature Schnauzer puppies ( 8 ) , Yorkshire terrier puppies required lower energy intake to maintain ideal body condition score than did Labrador retriever puppies until 23 weeks of age. The energy intakes of the miniature Schnauzer puppies were very similar to those of the Yorkshire terriers until 16 weeks of age when they diverged, possibly due to a longer rapid growth phase in the miniature Schnauzers.…”

“…1) was overestimated by the NRC (2006) ( 9 ) equation from 10 to 20 weeks of age whilst the values were comparable from 21 to 52 weeks of age with the exception of weeks 25 and 45. When compared with the energy requirement values reported by Brenten et al ( 8 ) (Fig. 2), there was a significant interaction of breed with time ( P  < 0·0001) with the energy intake of Yorkshire terriers being significantly less than that of Labrador retrievers from 10 to 29 weeks of age ( P  ≤ 0·05) by 77·4 (95 % CI 132·6, 61·1) to 376·6 (95 % CI 477·4, 275·3) kJ/kg 0·75 .…”

“…Neither equation, however, accounts for differences in breed. Brenten et al ( 8 ) investigated the energy requirements of miniature Schnauzer and Labrador retriever puppies and observed that for miniature Schnauzer puppies, the NRC equation initially overestimates and subsequently underestimates energy requirements while those of Labrador retrievers were met. As accurate feeding guides are vital for healthy growth in puppies, the primary objective of this study was to investigate the energy requirements of a toy breed, namely the Yorkshire terrier, from 10 weeks to 1 year of age.…”

Growth standard charts for monitoring bodyweight in dogs of different sizes

“…Therefore, unlike the WHO growth standards, it is unlikely that a single growth standard could be created that could be applied to all dogs. Furthermore, whilst previous studies have reported how bodyweight changes during the growth phase for a small number of breeds [ 10 , 11 , 12 , 13 , 14 ], such data are not sufficient for creation of growth curves for all breeds and sizes.…”

Age‐associated and breed‐associated variations in haematological and biochemical variables in young labrador retriever and miniature schnauzer dogs

“…For MCV and MCH a significant effect of breed was observed with miniature schnauzers having significantly higher MCV and MCH throughout the trial. It can be speculated whether the smaller RBC size in labrador retriever presents an adaptation to the higher metabolic rate ( Brenten and others 2014 ) providing an increased surface area for oxygen exchange ( Hawkey 1975 ).…”