Abstract
Clinical findings and thyroid function were examined in8 growth-retarded Japanese Black cattle. Until about 3 or4 months of age, the animals had grown normally and had had normal appetites. At initial examination (3 to 13 months of age), however, their bodies were very small, though normally proportioned. Laboratory tests revealed no characteristic findings. Three of the cattle had poor appetites and were largely inactive. Their basal serum total triiodothyronine (T3) concentrations and serum total thyroxine (T4) concentrations were low. Thyrotrophin-releasing hormone (TRH) stimulating tests showed serum total T4concentrations to have increased in2 animals and to have remained at a low level in one. Of five animals demonstrating normal appetite and activity, serum total T4concentrations were normal in 1, moderately low in 2, and very low in 2. These concentrations increased in all5 after TRH stimulation. These8 growth-retarded animals may have been suffering from the euthyroid sick syndrome.
