Congenital joint laxity and disproportionate dwarfism in a herd of beef cattle

摘要

Three calves from a herd of beef cattle on Prince Edward Island, Canada, were examined in May 1997 because of disproportionate dwarfism and excessive extension of metacarpophalangeal and metatarsophalangeal joints. Abnormalities had been noticed atbirth, 1-6 days earlier. A thorough herd investigation revealed that 16 calves born to 70 multiparous cows were affected during the calving season. The condition did not adversely affect calf survival. Affected calves had limbs that were disproportionately short, compared with their trunk size, and wide epiphyses of the femurs and humeri. Radiographic evaluation revealed incomplete maturation of carpal and tarsal bones and incomplete maturation and abnormal flaring of epiphyses of the short humeri and femurs. Histological findings were consistent with chondrodystrophy. This disorder had not been seen in the herd in previous years and was traced to feeding of dry, spoiled silage to the dams during mid-gestation. Covering the silage prevented problems inthe subsequent year. It is suggested that a fungal toxin most likely caused the outbreak.