RESUMEN
Profitability of sheep production depends on the reproductive response of ewes and growth of their lambs, which can be improved through the ram genotype. The aim of this study was to evaluate the reproductive response of Blackbelly (Bb), Pelibuey (Pb), Katahdin (Kat) and Dorper (Dor) ewes crossed with Damara (Dam) and Dor rams and the growth of their offspring. To measure percentage of single and multiple lambings (MLP), 234 Bb, Pb, Kat and Dor ewes were used. To measure lamb growth, the offspring of 86 Bb x Pb (BbPb) ewes and 73 Kat x Dor (KatDOR) ewes were used. Four Dor x BbPb, six Dam x BbPb and six Dam x KatDor lambs were slaughtered for carcass assessment. MLP was analyzed with the CATMOD procedure considering the factors age and breed. Lamb growth data were analyzed with the MIXED procedure, and those of carcass characteristics with the GLM procedure of SAS, using weight at slaughter as covariable. MLP was higher (P<0.05) in Bb than in Dor. The Dor x BbPb lambs were heavier (P<0.05) at birth than Dam x BbPb. Of the lambs from single and multiple births, the KatDor lambs were heavier (P<0.05) at birth than BbPb lambs. The female lambs of Dor rams had higher (P<0.05) weight gain after weaning than those of Dam rams. Carcass dressing, subcutaneous fat, and primal cut yield were not different (P>0.05) by effect of ram breed. It is concluded that Bb ewes are more prolific than Dor ewes; male lambs of Dam rams had post-weaning growth response and carcass yield similar to those of Dor rams, although the female lambs of Dor rams were heavier than those of Dam rams.(AU)
Rentabilidade da produção de ovinos depende da resposta reprodutiva de ovelhas e do crescimento de seus cordeiros, o que pode ser melhorado por meio do genótipo masculino. O objetivo deste estudo foi avaliar o desempenho reprodutivo de ovinos Blackbelly (Bb), Pelibuey (Pb), Katadin (Kat) e Dorper (Dor) e o crescimento de cordeiros com carneiros Damara (Dam) e Dor. Para medir a porcentagem de partos simples e múltiplas (MLP), foram utilizados 234 ovelhas Bb, PB, Kat e Dor. Para medir o crescimento dos cordeiros, foram utilizadas 86 ovelhas Bb x Pb (BbPb) e 73 Kat x Dor (KatDOR). Quatro cordeiros Dor x BbPb, seis Dam x BbPb e seis Dam x KatDor foram sacrificados para avaliação de carcaça. MLP foi analisada com o procedimento CATMOD, considerando-se fatores como idade e raça. Dados de crescimento do cordeiro foram analisados com o procedimento MIXED, e as de características de carcaça com o procedimento GLM do SAS, utilizando-se peso ao sacrifício como covariável. MLP foi maior (P<0.05) em Bb do que em Dor. Os cordeiros Dor x BbPb foram mais pesados (P<0.05) no nascimento do que Dam x BbPb. Em partos simples e múltiplos, os cordeiros de ovelhas KatDor foram mais pesados (P<0.05) no momento do nascimento de cordeiros BbPb. As cordeiras de carneiros Dor apresentaram maior (P<0.05) ganho de peso após o desmame do que as de carneiros Dam. O rendimento de carcaça, a espessura da gordura subcutânea e o rendimento de corte primal não foram diferentes por efeito da raça de carneiro. Conclui-se que as ovelhas Bb são mais prolíficas do que as ovelhas Dor; cordeiros de carneiros Damara tiveram resposta de crescimento pós-desmame e rendimento de carcaça semelhantes aos dos carneiros Dor, embora Dorper cordeiras fossem mais pesadas do que as de Damara.(AU)
Asunto(s)
Animales , Tamaño de la Camada/genética , Reproducción/genética , Ovinos/genética , Ovinos/crecimiento & desarrollo , Destete , Aumento de Peso , Fenómenos Fisiológicos Reproductivos/genéticaRESUMEN
Profitability of sheep production depends on the reproductive response of ewes and growth of their lambs, which can be improved through the ram genotype. The aim of this study was to evaluate the reproductive response of Blackbelly (Bb), Pelibuey (Pb), Katahdin (Kat) and Dorper (Dor) ewes crossed with Damara (Dam) and Dor rams and the growth of their offspring. To measure percentage of single and multiple lambings (MLP), 234 Bb, Pb, Kat and Dor ewes were used. To measure lamb growth, the offspring of 86 Bb x Pb (BbPb) ewes and 73 Kat x Dor (KatDOR) ewes were used. Four Dor x BbPb, six Dam x BbPb and six Dam x KatDor lambs were slaughtered for carcass assessment. MLP was analyzed with the CATMOD procedure considering the factors age and breed. Lamb growth data were analyzed with the MIXED procedure, and those of carcass characteristics with the GLM procedure of SAS, using weight at slaughter as covariable. MLP was higher (P<0.05) in Bb than in Dor. The Dor x BbPb lambs were heavier (P<0.05) at birth than Dam x BbPb. Of the lambs from single and multiple births, the KatDor lambs were heavier (P<0.05) at birth than BbPb lambs. The female lambs of Dor rams had higher (P<0.05) weight gain after weaning than those of Dam rams. Carcass dressing, subcutaneous fat, and primal cut yield were not different (P>0.05) by effect of ram breed. It is concluded that Bb ewes are more prolific than Dor ewes; male lambs of Dam rams had post-weaning growth response and carcass yield similar to those of Dor rams, although the female lambs of Dor rams were heavier than those of Dam rams.(AU)
Rentabilidade da produção de ovinos depende da resposta reprodutiva de ovelhas e do crescimento de seus cordeiros, o que pode ser melhorado por meio do genótipo masculino. O objetivo deste estudo foi avaliar o desempenho reprodutivo de ovinos Blackbelly (Bb), Pelibuey (Pb), Katadin (Kat) e Dorper (Dor) e o crescimento de cordeiros com carneiros Damara (Dam) e Dor. Para medir a porcentagem de partos simples e múltiplas (MLP), foram utilizados 234 ovelhas Bb, PB, Kat e Dor. Para medir o crescimento dos cordeiros, foram utilizadas 86 ovelhas Bb x Pb (BbPb) e 73 Kat x Dor (KatDOR). Quatro cordeiros Dor x BbPb, seis Dam x BbPb e seis Dam x KatDor foram sacrificados para avaliação de carcaça. MLP foi analisada com o procedimento CATMOD, considerando-se fatores como idade e raça. Dados de crescimento do cordeiro foram analisados com o procedimento MIXED, e as de características de carcaça com o procedimento GLM do SAS, utilizando-se peso ao sacrifício como covariável. MLP foi maior (P<0.05) em Bb do que em Dor. Os cordeiros Dor x BbPb foram mais pesados (P<0.05) no nascimento do que Dam x BbPb. Em partos simples e múltiplos, os cordeiros de ovelhas KatDor foram mais pesados (P<0.05) no momento do nascimento de cordeiros BbPb. As cordeiras de carneiros Dor apresentaram maior (P<0.05) ganho de peso após o desmame do que as de carneiros Dam. O rendimento de carcaça, a espessura da gordura subcutânea e o rendimento de corte primal não foram diferentes por efeito da raça de carneiro. Conclui-se que as ovelhas Bb são mais prolíficas do que as ovelhas Dor; cordeiros de carneiros Damara tiveram resposta de crescimento pós-desmame e rendimento de carcaça semelhantes aos dos carneiros Dor, embora Dorper cordeiras fossem mais pesadas do que as de Damara.(AU)
Asunto(s)
Animales , Tamaño de la Camada/genética , Ovinos/crecimiento & desarrollo , Ovinos/genética , Aumento de Peso , Destete , Reproducción/genética , Fenómenos Fisiológicos Reproductivos/genéticaRESUMEN
Profitability of sheep production depends on the reproductive response of ewes and growth of their lambs, which can be improved through the ram genotype. The aim of this study was to evaluate the reproductive response of Blackbelly (Bb), Pelibuey (Pb), Katahdin (Kat) and Dorper (Dor) ewes crossed with Damara (Dam) and Dor rams and the growth of their offspring. To measure percentage of single and multiple lambings (MLP), 234 Bb, Pb, Kat and Dor ewes were used. To measure lamb growth, the offspring of 86 Bb x Pb (BbPb) ewes and 73 Kat x Dor (KatDOR) ewes were used. Four Dor x BbPb, six Dam x BbPb and six Dam x KatDor lambs were slaughtered for carcass assessment. MLP was analyzed with the CATMOD procedure considering the factors age and breed. Lamb growth data were analyzed with the MIXED procedure, and those of carcass characteristics with the GLM procedure of SAS, using weight at slaughter as covariable. MLP was higher (P0.05) by effect of ram breed. It is concluded that Bb ewes are more prolific than Dor ewes; male lambs of Dam rams had post-weaning growth response and carcass yield similar to those of Dor rams, although the female lambs of Dor rams were heavier than those of Dam rams.
Rentabilidade da produção de ovinos depende da resposta reprodutiva de ovelhas e do crescimento de seus cordeiros, o que pode ser melhorado por meio do genótipo masculino. O objetivo deste estudo foi avaliar o desempenho reprodutivo de ovinos Blackbelly (Bb), Pelibuey (Pb), Katadin (Kat) e Dorper (Dor) e o crescimento de cordeiros com carneiros Damara (Dam) e Dor. Para medir a porcentagem de partos simples e múltiplas (MLP), foram utilizados 234 ovelhas Bb, PB, Kat e Dor. Para medir o crescimento dos cordeiros, foram utilizadas 86 ovelhas Bb x Pb (BbPb) e 73 Kat x Dor (KatDOR). Quatro cordeiros Dor x BbPb, seis Dam x BbPb e seis Dam x KatDor foram sacrificados para avaliação de carcaça. MLP foi analisada com o procedimento CATMOD, considerando-se fatores como idade e raça. Dados de crescimento do cordeiro foram analisados com o procedimento MIXED, e as de características de carcaça com o procedimento GLM do SAS, utilizando-se peso ao sacrifício como covariável. MLP foi maior (P<0.05) em Bb do que em Dor. Os cordeiros Dor x BbPb foram mais pesados (P<0.05) no nascimento do que Dam x BbPb. Em partos simples e múltiplos, os cordeiros de ovelhas KatDor foram mais pesados (P<0.05) no momento do nascimento de cordeiros BbPb. As cordeiras de carneiros Dor apresentaram maior (P<0.05) ganho de peso após o desmame do que as de carneiros Dam. O rendimento de carcaça, a espessura da gordura subcutânea e o rendimento de corte primal não foram diferentes por efeito da raça de carneiro. Conclui-se que as ovelhas Bb são mais prolíficas do que as ovelhas Dor; cordeiros de carneiros Damara tiveram resposta de crescimento pós-desmame e rendimento de carcaça semelhantes aos dos carneiros Dor, embora Dorper cordeiras fossem mais pesadas do que as de Damara.
Asunto(s)
Animales , Aumento de Peso , Destete , Ovinos/crecimiento & desarrollo , Ovinos/genética , Reproducción/genética , Tamaño de la Camada/genética , Fenómenos Fisiológicos Reproductivos/genéticaRESUMEN
Direct and maternal breed effects on birth and 200-d weights were estimated for nine parental breeds (Hereford [H], Angus [A], Braunvieh [B], Limousin [L], Charolais [C], Simmental [S], Gelbvieh [G], Red Poll [R], and Pinzgauer [P]) that contributed to three composite populations (MARC I = 1/4B, 1/4C, 1/4L, 1/8H, 1/8A; MARC II = 1/4G, 1/4S, 1/4H, 1/4A; and MARC III = 1/4R, 1/4P, 1/4H, 1/4A). Records from each population, the composite plus pure breeds and crosses used to create each composite, were analyzed separately. The animal model included fixed effects of contemporary group (birth year-sex-dam age), proportions of individual and maternal heterosis and breed inheritance as covariates, and random effects of additive direct genetic (a) and additive maternal genetic (m) with covariance (a,m), permanent environment, and residual. Sampling correlations among estimates of genetic fixed effects were large, especially between direct and maternal heterosis and between direct and maternal breed genetic effects for the same breed, which were close to -1. This resulted in some large estimates with opposite sign and large standard errors for direct and maternal breed genetic effects. Data from a diallel experiment with H, A, B, and R breeds, from grading up and from a top cross experiment were required to separate breed effects satisfactorily into direct and maternal genetic effects. Results indicate that estimation of direct and maternal breed effects needed to predict hybrid EPD for multibreed populations from field data may not be possible. Information from designed crossbreeding experiments will need to be incorporated in some way.