Associação genética entre a mudança de peso vivo e características relacionadas à fertilidade e à habilidade materna de ovelhas Santa Inês

• Ano de defesa: 2016
• Autor(a) principal: Muniz, Lorena Mirelle Santos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Avaliação genética multivariada; Correlações genéticas; Herdabilidade; Inferência bayesiana; Número de crias desmamadas; Peso total de crias ao nascimento
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/21594

As Santa Inês is the breed with the largest number of animals available in Brazil, which makes it the maternal base of the country's meat sheep industry, and in the moment that signals to need to increase the effective size of the flocks, to meet the suppressed domestic demand by meat lamb, evaluate the reproductive performance of this breed is a fundamental issue. As in meat production, much emphasis is given to growth traits over those of fertility, the aim of this study was to investigate a possible association between the change in body weight in the pre- and post-partum, and traits related to fertility and maternal ability of Santa Ines sheep. The analyzed traits were mating weight (MW), lambing weight (LW) and weight of the ewe at weaning of their lambs (WW), number of lambs born per ewe (NLB), number of lambs weaned per ewe (NLW), total weight of lambs born per ewe (LWB) and total weight of lambs weaned per ewe (LWW), weight change between mating and lambing (WC1 = (LW – MW)/(lambing date – mating date)) and weight change between lambing and weaning (WC2 = (WW – PP)/(weaning date – lambing date)) of 2,166 ewes, from 2004 to 2010. Four multivariate animal models were analyzed: 1) Limiar2 x Linear2 (NLB, NLW, WC1 and WC2), 2) Linear4 (LWB, LWW, WC1 and WC2), 3) Linear3 x Limiar2 (MW, LW, WW, NLB and NLW) and 4) Linear5 (MW, LW, WW, LWB and LWW) by Bayesian inference with THRGIBBS1F90 and GIBBS2F90 software. The heritabilities for NLB, NLW, LWB, LWW, WC1, WC2, MW, LW and WW were 0.24, 0.24, 0.15, 0.10, 0.07, 0.01, 0.40, 0.44 and 0.44, respectively. The mode estimation for genetic correlation between WC1 and WC2 was equal to 1.0. Genetic correlations of WC1 and WC2 with the traits NLB, NLW, LWB and LWW tended to be negative. We conclude that ewes which do not show major changes in their body weight, in the period close to lambing, are more efficient and should be selected to improve flock productivity. This aspect should be associated with a greater number of lambs weaned per ewe.