Effect of administration of estradiol and progesterone, and bacterial contamination, on endometrial morphology of acyclic mares

Abstract

Acyclic mares (free of uterine infection and with typical acyclic endometria on biopsy) received daily intramuscular injections in oil of either 1.5 mg estradiol benzoate ( n - 4) or progesterone ( n = 5). Estradiol and progesterone treatment induced biopsy changes consistent with estrus or diestrus respectively (Kenney, 1978). Subsequently, seven mares with typical acyclic endometria were given ten daily intra-uterine infusions of from 400 to 10 000 pg estradiol-17β. All mares developed Streptococcus zooepidemicus infections which masked any endometrial changes which might have been induced by estradiol infusion.