Progesterone treatment of anovulatory mares

Abstract

This study took place over a 3 year period and was conducted in 4 phases. In total, 40 mares of stock horse type were used. All mares were in good health, but had failed to conceive or did not give birth to a live foal from the preceding year's breeding. In phase one, 6 mares were separated in to 3 groups of 2 mares each. Each group received an intramuscular injection of 17-hydroxyprogesterone-n-caproate (17-OHPC), Delalutin. Group I received 125 mg; group II, 250 mg and group III, 375 mg of 17-OHPC. The results were not conclusive. In phase two, 9 mares were randomly divided in to 3 groups of 3 mares each. Group I received 20 mg; group II, 30 mg; and group III, 40 mg of 17-0HPC per 100 pounds body weight. The treatment groups did not differ significantly in number of days in estrus, number of days from ovulation to the next 3 cm follicle, number of days from a 3 cm follicle to ovulation, or conception rate. When the data accumulated from the treated groups were compared to similar data recorded from normal mares a significant difference (P <0.05) was calculated for the number of days from ovulation to the next 3 cm follicle, with the mean time being 7 days less for the treated mare is. In phase three, 15 mares were randomly divided in to 3 groups of 5 mares each. Group I received 40 mg of 17-OHPC per 100 pounds body weight, group II received 20 mg of 17-OHPC per 100 pounds body weight, and group III was designated as the control. There were no significant differences between groups for number of days in estrus. ...