Skeletal development of greyhounds, German shepherd dogs and their crossbreed offspring. An investigation with special reference to hip dysplasia.
Skeletal development (appearance of secondary ossification centers) of Greyhounds, German Shepherds and their crossbreed offspring was studied. It was found that Greyhounds were more mature at birth than German Shepherds. Crossbreeds held an intermediate position. After about 16 weeks the skeletal age of German Shepherds was more advanced than that of Greyhounds and Crossbreeds. Of 28 German Shepherds which were radiographed at 6 months of age 6 (21%) had hip dysplasia. Four of these were sacrificed and necropsied together with 3 radiographically normal litter mates. These "normal" pups had incipient macroscopic and histologic signs of hip dysplasia. All Greyhounds and Crossbreeds, which were radiographed at about 6 months of age, had normal hips. Three Greyhounds and 7 Crossbreeds were necropsied at 6 months of age. Their hip joints were normal. All German Shepherds had unstable hips (post mortem) from an age of 4 weeks while Greyhounds and Crossbreeds had stable or only slightly unstable hips. On the basis of previous experiments with estradiol induced hip dysplasia it was suggested that German Shepherd are under influence of more maternal estrogens during fetal life than Greyhounds and Crossbreeds. The accelerated skeletal maturation and early sexual maturity of German Shepherds indicate an early and/or higher production of endogenous estrogens, which retards growth of cartilage, initiating the vicious circle of hip dysplasia. It was concluded that investigations of estrogen levels and further studies of skeletal development of dogs with and without hip dysplasia are necessary before any definite conclusion on etiology and pathogenesis of spontaneously occurring hip dysplasia can be drawn.
D000818:Animals; D001846:Bone Development; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D004285:Dogs / Q000254:growth & development*; D005260:Female; D006618:Hip Dislocation, Congenital / Q000662:veterinary; D006619:Hip Dysplasia, Canine / Q000000981:diagnostic imaging / Q000473:pathology; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D011859:Radiography; D012741:Sexual Maturation