Reproductive parameters on hair sheep (Morada Nova and Santa Inês) reared in intensive systems in Southeastern Brazil

Abstract

In southeastern Brazil, the Santa Inês ewes is one of the most used to produce early slaughtering crossbred lambs. The Morada Nova breed is reared only in some regions of Brazil and has a very small number of animals and flocks, but ewes have potential to be used for lamb production in the southeast, due to their adaptability to tropical conditions. This experiment aims to evaluate the reproductive potential of Morada Nova ewes to produce early lambs for slaughter. The study was carried out at Instituto de Zootecnia, city of Nova Odessa, located in São Paulo State, Brazil. Forty-nine adult Santa Inês (SI) ewes with 51.8 ± 7.07 kg of initial body weight and forty-nine Morada Nova (MN) with 33.1 ± 4.98 were used. During pregnancy the ewes were reared on intensive grazing systems with rotational grazing on Aruana grass pasture (Panicum maximum cv.IZ-5), and in the final third of gestation received corn silage ad libitum and a concentrate mixture (400 g/day) with 16% crude protein and 80% of total digestible nutrient (TDN). The length of pregnancy, calculated through the date of mating and date of birth; prolificacy rate obtained by the number of lambs born per ewes; percentage of multiple births (%) and ewe’s weight at lambing (kg) were calculated. Statistical analysis was carried using GLM procedure of SAS ®. The birth weight of MN ewes was lower than the SI ewes, which is a reflection of their smaller size, however, the other reproductive parameters were similar between genotypes. These results highlight the potential use of Morada Nova ewes, as smaller maternal breed, for lamb production, which is favorable for production system that seeks sustainable intensification and optimization of resources, especially food.