A study of ossification of carpal and tarsal bones in normal and hypothyroid foals.

The degree of ossification of carpal and tarsal bones was determined in normal foals of various ages and in hypothyroid and thyroidectomized foals. In normal foals ossification occurred very rapidly in the last few weeks of gestation and less rapidly from birth to 33 days. The ulnar carpal bone was consistently less ossified than other carpal or tarsal bones. Foals with congenital hyperplastic goitre had retarded ossification of the cuboidal bones, especially the central and third tarsal bones. Thyroidectomized foals had retarded ossification of lesser degree.