Thyroid function in primary ketosis.

The authors compared the thyroid function of cows with primary ketosis and clinically healthy cows in the same stage of lactation by a method based on the in vitro erythrocyte uptake of L-3,5,3′- triiodothyronine labelled with I131. This method (EU) proved to be affected by, among other factors, the content of total protein in the blood plasma, which was lower in ketotic than in normal cows. This caused difficulties in interpretation of the measured EU, but the authors consider that the experiments indicated an elevated thyroid activity in ketosis. The importance of continued research into the probable relation between thyroid function and ketosis is stressed.