1991 Volume 44 Issue 11 Pages 1098-1101
One hundred and one calves, 99 Holstein calves and 2 Japanese Black beef calves, were reared in the Tokachi District and carried to a meat inspection center. Their thyroids were subjected to a weighing, histological examination and measurement of serum thyroid hormone. Thyroid weight for 43 calves (42.6%) were below 15g, 46 calves (45.5%) from 15g to 30g and 12 calves (11.9%) over 30g. Histologically, 4 of 12 calves over 30g of thyroid weight showed a diffuse parenchymatous goiter. The serum thyroxine (T4) levels of these 4 cases decreased slightly but the serum triiodothyronine (T3) levels increased significantly. Therefore, the T4/T3 ratio was very low.
Consequently, many cases which seemed healthy had goiter caused by iodine deficiency, and it was determined that the Tokachi District is a region where enzootic goiter is prevalent.