THE EFFECT OF THYROID DEFICIENCY ON THE OESTROUS CYCLE AND CONCEPTION IN THE EWE

Abstract

SUMMARY: One half of a flock of twenty-four 3- to 4-year-old Merino ewes were thyroidectomized and the other half subjected to a sham-operation, oestrous cycles being recorded before and after surgery in both groups. A year later a record was again kept of oestrous cycles, and in both series of observations there were no apparent changes due to thyroidectomy. An intact ram was run with the flock on two occasions, at 3 and 14 months, after thyroidectomy. As judged by lambing in the first instance, and dissection in the second, there were no effects of thyroidectomy on conception. It was concluded that thyroidectomy has no apparent influence on the oestrous cycle and conception in the ewe.