Retained placenta in Friesian mares: reproductive performance after foal heat breeding versus breeding in a subsequent heat

Postpartum reproductive performance was studied in 54 Friesian brood mares with and 50 without retained placenta. Retained placenta was defined as fai lure to expel all fetal membranes within 3 hours after the delivery of the foal. The group of mares with retained placenta was subdivided into mares i n which the placenta had been removed manually (n=30) and mares in which it was not (n=24). Within each group, reproductive performance after breeding in the foal heat and breeding in a subsequent heat was compared. Age of the mares, number of mares treated with antibiotics after inseminati on, and number of mares treated with prostaglandins were recorded. The inte rval between delivery and conception, efficacy rate, seasonal pregnancy rat e, pregnancy rate after first insemination, pregnancy loss rate, and foolin g rate did not differ between the mares with, and without retained placenta or between the mares with and without manual removal of the retained place nta. Within each group, the pregnancy rate after first insemination did not differ between breeding for the first time in the foal heat and breeding f or the first time in a subsequent heat. It is concluded that reproductive performance did not differ between 1) Fri esian mares with and without retained placenta and, 2) Friesian mares with and without manual removal of the placenta. With regard to reproductive per formance, retained placenta and manual removal of the placenta are not vali d reasons to avoid foal heat breeding in Friesian mares.