A Comparison of two dosages of prostaglandin F2α for the treatment of functional anestrus in dairy cattle

Abstract

Two dosages (25 and 50 mg) of prostaglandin F2a (Lutalyse) were compared for the treatment of functional anestrus in two herds of Holstein cattle. Response was measured by percent in estrus within five days after treatment, percent pregnant of those bred, and percent pregnant of total treated. Doubling the recommended dosage (25 mg) had no effect on response in either herd. Nor were there any differences in response between lightweight and heavyweight cows. Heifers were significantly more responsive than cows. Of those exhibiting estrus after treatment 81% were observed on days three and four, and 6.2% developed ovarian cysts by the first examination after an unresponsive treatment. In one herd there were significantly less animals observed in estrus in the summer when compared to the other three seasons.