Abstract
Factors affecting the occurrence of an abnormal cartilage formation in the bones of young chicks have been studied. The condition occurs in chicks fed a purified diet and is prevented by the use of natural feed ingredients. The incidence of this abnormality can be increased by genetic selection. The abnormal cartilage formation is characterized by an accumulation of immature chondrocytes in the proximal metaphyses of the tibiotarsus and tarsometatarsus. The microscopic appearance is similar to the lesion observed with copper deficiency; however, dietary copper does not prevent it in chicks fed the purified diets. Deficiences of other nutritional factors known to affect bone formation did not produce a lesion similar to the abnormal cartilage formation. The purified diet used to produce the deformity was not improved by increased amounts of individual vitamins and minerals. No concentrated source of abnormal cartilage-preventing activity was observed in the natural feedstuffs studied. Thus, the nutritional factor(s) involved in the prevention of this condition is (are) unknown at the present time.