REPRODUCTIVE PERFORMANCE OF DORPER AND KATAHDIN EWES BRED IN SPRING SEASON IN THE NORTHERN MEXICO

Abstract

This study compared the ability of breeds Dorper and Katahdin to reproduce out of season. The ewes were kept in confinement conditions and fed with a whole diet (23.4% DM, 12.7% of CP and 2.3 Mcal ME). The sheep were exposed to males of their respective breeds in March-April (217 Dorper and 72 Katahdin) and in May-June (103 Dorper and 37 Katahdin).  The proportion of ewe lambed was higher (P < 0.0001) in two breeds bred in March-April (67.7 and 72.2%) than May-June (38.8 and 29.7%), but prolificacy was similar (P > 0.05) in both breeds in the two breeding periods (1.35, 1.35, 1.15 and 1.36 lambs born/ewe lambed in the March-April and May-June breeding, in the Dorper and Katahdin breeds, respectively). It is concluded that ewes of hair Dorper and Katahdin sheep are able to reproduce outside of the reproductive season, in Durango, Mexico. However, reproductive efficiency was increased in ewes bred at the beginning than those bred at the end of spring season.