EVALUATION OF MATERNAL BREEDS IN CROSSING WITH DORPER BREED SHEEP IN THE EARLY PRODUCTION OF SLAUGHTER LAMBS

Abstract

Performance and parasitic infection will be evaluated in sheep Morada Nova and Santa Inês besides performance and carcass traits and meat from their offspring in feedlot. Will be utilized 40 ewes Morada Nova and 40 Santa Ines. Twenty ewes from each breed group will be mated with Dorper ram to obtain the F1 (½ Morada Nova x ½ Dorper e ½ Santa Inês x ½ Dorper) and the remainder will be mated with the same genetic group to obtain the pure breeds. The ewes will be kept on Panicum maximum cv. Aruana, supplemented when necessary with concentrate and roughage. Ewes will be following up during pregnancy, lactation and weaning also the parasitic infection (OPG and Famacha), body weight will be considered. Blood samples will be obtained during late pregnancy, parturition and lactation (30 and 60 days) to determine the concentration of ²-hydroxybutyrate to quantify the increase in lipid mobilization. The lambs will be weighed at birth and during lactation (30 and 60 days) and finished in feedlot with high concentrate diet. Performance will be evaluated in feedlot and slaughtered when they reach 35 kg live weight. After slaughter carcasses will be weigh and evaluated for different carcass measurements as (degree of conformation, carcass fat, loin eye measurements and chemical composition of meat) also the chemical composition of the 12th rib, the proportion of commercial cut and tissues, meat color, pH, shear force, cooking loss, water retention capacity and fatty acid profile of meat will be carried out.