Progesterone assays and rectal palpation in pre-service management of a dairy herd

Fifty-one dairy cows were examined three times at weekly intervals during weeks 5 to 7 after calving. Rectal palpation of the ovaries and plasma progesterone assay were used to determine cyclic ovarian function. Eight of 51 cows exhibited true anoestrus by day 49 after calving. Only 23 of 43 cycling cows were served by day 77, the end of the target period for first service. In 77 per cent of 142 examinations, rectal palpation and progesterone assay gave compatible results. Most incompatibility occurred early or late inthe cycle, or in association with cystic structures in the ovaries. Eleven of the 51 cows had cysts in the ovaries but cyclicity and fertility were not adversely affected.