Body-weight changes during growth in puppies of different breeds

As a species, the dog is unique. Depending on the breed, body weight varies 100-fold from the 1-kg Chihuahua to the 115-kg St. Bernard (1). The time taken for a growing puppy to achieve adult body weight also varies considerably with larger breeds having a longer growth period than smaller breeds. Also the rate of growth during this period is not constant; energy requirements decrease from 3 times maintenance at weaning to1.2 times maintenance as the puppy approaches adulthood (1). The provision of accurate feeding guides is essential if under- and overnutrition are to be prevented. Overnutrition of dogs results in obesity, but in large breeds overnutrition also causes musculoskeletal disorders (2,3). However, present feeding guides are based on "typical" growth data that use only a single equation (4,5). Breed-specific differences in growth patterns might be expected due to huge variations in size, temperament, and coat type, all of which are likely to affect energy requirements. This was evident in a study of six breeds of puppies that demonstrated very different energy requirements despite similar absolute body weights in Great Danes versus Newfoundlands and Briards versus Labrador Retrievers (6). Little information is published on breed-specific variations in puppy growth patterns, and most studies provide only limited data on single breeds, for example, 8-34-mo-old and 6-20-wk-old Labrador Retrievers (7,9) and 0-12-wk-old German Shepherds (8). Other studies are confounded by the use of different groups of dogs to provide data for a variety of age groups (10). Comparisons between these studies are difficult due to differing data presentation and treatment. The aim of this study was to compare the complete growth curves of 12 different-sized dog breeds and to investigate a mathematical basis for the provision of breed-specific feeding guides.