Effects of limited food consumption on the incidence of hip dysplasia in growing dogs

Summary Forty-eight 8-week-old Labrador Retrievers were allotted to 2 groups of 24 dogs each; 1 group was fed ad libitum and the other group was given 25% less of the same feed until the dogs were 2 years old. Radiography of the hip joints was done when the dogs were 30, 42, 54, 78, and 104 weeks old. Subluxation was measured by the Norberg angle on radiographs made with the dog in the standard (extended limb) position. Independent of age at which the radiography was done, there was less subluxation of the femoral heads in the limit-fed dogs. Using the Swedish method of hip joint evaluation on the same radiographs, it was found that fewer dogs on limited food intake had signs of hip dysplasia. Radiographs done when dogs were 2 years old, for all the methods used (Norberg angle in standard and frog-limb position, the Orthopedic Foundation for Animals ofa score, and the Swedish score), revealed less hip dysplasia (less joint subluxation and less degenerative joint disease) in the limit-fed dogs. Using the ofa method, 7 of the 24 limit-fed dogs and 16 of the 24 ad libitum-fed dogs were diagnosed as having hip dysplasia. Similarly, using the Swedish method, 5 of the 24 limit-fed dogs and 18 of the 24 ad libitum- fed dogs were diagnosed as having hip dysplasia. The food-intake-related differences were significant both for the ofa score and for the Swedish score. There was a significant correlation between the Norberg angle measured on radiographs made with the dog in the standard position when it was 30 weeks old and the result obtained when the dog was 2 years old by the ofa and Swedish methods. The findings support the clinical recommendation to avoid overfeeding of growing dogs, particularly in breeds prone to canine hip dysplasia.