The live foaling rate per cycle in mares

Abstract

Summary The overall live foaling percentage per cycle on 4 Kentucky Thoroughbred farms was 42.0%. The rate varied with mare reproductive status, mare age, cycle number and stallion. The most pronounced effect was associated with mare age. Estimates of the relative importance of embryonic loss as a factor limiting reproductive success for young and old mares. suggest that young mares lose half of their embryos from fertilisation to term, and the loss rate increases with mare age to the point that old mares lose all or nearly all of their embryos.