Response of serum LH and milk progesterone to two GnRH agonists, fertirelin and buserelin, in cows with ovarian follicular cysts

Abstract

Follicular cysts were diagnosed in 172 Holstein cows by rectal palpation, and the diagnosis was confirmed in 41.3% of the cows, using 3 consecutive milk progesterone tests. For 57 cows with cysts, treated with 200 μg fertirelin or 20 μg buserelin 14 days after first examination, the average serum LH concentration 2.0-2.5 h after treatment was 22.5 and 20.6 ng/ml respectively, and luteinization occurred in 76.7 and 66.7% of cows. Of cows treated with fertirelin and buserelin, 75 and 72% respectively showed an increase in milk progesterone to ?1.0 ng/ml. The percentage of cows conceiving within 180 days of treatment was 70.8 and 61.9% respectively in the 2 groups, and the service period averaged 71±41 and 63±53 days respectively. The differences between treatments were not significant.