Gonadotropin-Releasing Hormone and Prostaglandin F2α for Postpartum Dairy Cows: Estrous, Ovulation, and Fertility Traits

Abstract

A study of 234 Holstein cows was conducted to determine if early postpartum treatments of gonadotrophin-releasing hormone, prostanglandin F2.alpha., or both would alter frequency and occurrence of estrus and ovulation as well as subsequent fertility. Cows in groups 1 and 2 received gonadotropin-releasing hormone (200 .mu.g) between 10 and 14 d postpartum, and cows in groups 3 and 4 received saline. Ten days later, cows in groups 2 and 3 received prostaglandin F2.alpha. (25 mg), and cows in groups 1 and 4 received saline. Treatment with gonadotropin-releasing hormone reduced intervals to first ovulation and first detected estrus as well as increasing the proportion of cows with three or more ovalations before first serve from 57% for saline-treated controls to 83%. Treatment with prostaglandin F2.alpha. reduced intervals to second and third ovulation and shortened the first estrous cycle. Treatments for cows in groups 1 and 3 increased the proportion of cows having estrous cycles of normal duration. Interval from calving to conception was reduced by 43 to 48 d for cows with an abnormal puerperium treated with either gonadotropin-releasing hormone or prostaglandin F2.alpha. compared with controls (group 4) and by 27 to 29 d overall in all cows in groups 1 and 3. Cows with normal or abnormal puerperium in groups 1 and 3 required 26 to 41% fewer services per conception than controls. We conclude that treatments of gonadotropin-releasing hormone or prostaglandin F2.alpha., but not the treatment combination, improved fertility of dairy cows, especially those that experienced puerperal problems.