Reproductive performance of Finn sheep and crosses with subtropical breeds under accelerated lambing

Abstract

Reproductive performance of pure Finn (F), Rahmani (R) and Ossimi (O) sheep, F 1 crosses (FR and FO), back crosses to R (R·FR) and O (O·FO) and cross-bred sheep obtained by interbreeding (R·FR) 2 and (O·FO) 2 was studied under accelerated lambing. The data covered 18 successive mating seasons every eight months (September, May and January). High prolificacy of pure F ewes was maintained but low conception rate (CR) and high lamb losses markedly reduced number of lambs weaned per ewe joined (LWJ). Conception rate and number of lambs born per ewe lambing (LSB) were significantly higher in F 1 and backcross ewes than in local ewes. Superiority of first and back crosses over locals ranged between 23–28 and 10–15% in LSB, 32–34 and 21–23% in LWJ, on a per crop basis and 48–51 and 31–35% in LWJ on a per annum basis. Improvement in prolificacy of different crosses, however, was less than expected assuming linear increase with increasing F blood. Generally, the ewes performed better in September mating than in January or May. Seasonal variation in CR differed among genotypes while all breeds showed marked seasonal variation in prolificacy.