Reproductive performance of woolly and hairless crossbred ewes treated with an exogenous progestagen and eCG hormone during the non-breeding season

Abstract

The aim of this study was to evaluate the reproductive performance of woolly and hairless crossbred ewes treated with an exogenous progestagen and eCG hormone during the non-breeding season. Mixed breed ewes (n = 48) were assigned into two treatments considering the presence (G-Woolly, n = 25) or absence of wool (G-Hairless, n = 23). The ewes underwent hormone treatment to induction/synchronization of estrus, which consisted of the insertion of an intravaginal device randomly at the estrous cycle (D0). On Day 7, ewes were injected with eCG and d-cloprostenol. On Day 9, the device was removed and males were introduced into the herd (proportion of 1:6) twelve hours later during days 10, 11 and 12. After Day 12, males were separated from females for ten days and later reintroduced into the herd for 45 days. The rate of onset of estrus and the pregnancy rate from the synchronization was 84.0 and 36.0% vs. 87.0 and 56.6%, G-Woolly vs. G-Hairless (p> 0.05). The total pregnancy rate after male reintroduction was 68.0 vs. 91.3%, G-Woolly vs. G-Hairless (p< 0.05). In conclusion hairless crossbred ewes treated with the exogenous progestagen and eCG hormone during the non-breeding season presented higher reproductive performance compared to woolly crossbred ones.