Estimativas de parâmetros genéticos para características de crescimento, de carcaça e da carne em bovinos cruzados terminados em confinamento
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Data
2021-02-12
Autores
Gatti, Maurício [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A qualidade da carcaça e da carne de bovinos é cada vez mais importante para o setor produtivo, portanto estudos com características de crescimento, de carcaça e da carne de animais cruzados são fundamentais, pois o cruzamento permite explorar diferenças genéticas entre raças para atender os aspectos de qualidade do produto. Este trabalho teve como objetivo avaliar a viabilidade de utilização de raças exóticas em cruzamento com a raça Nelore, por meio de estimativas de efeitos aditivos diretos e heteróticos individuais e a viabilidade de seleção em população composta de animais cruzados, por meio de estimativas de parâmetros genéticos para as características peso ao final (PFIN; peso de abate) de confinamento, ganho de peso diário no confinamento (GPD), tempo de confinamento (TCON), consumo diário de matéria seca (CMS), peso de carcaça fria (PCF), rendimento de carcaça fria (RCF = PCF/PFIN), espessura de gordura subcutânea (EGAOL), área de olho de lombo (AOL) e as características da carne força de cisalhamento (FC), capacidade de retenção de água (CRA), pH e perda por cocção (PPC). Foram utilizados dados de animais Nelore e cruzados de Nelore com raças taurinas adaptadas (Bonsmara e Senepol), britânicas (Angus e Hereford) e continentais (Charolesa, Limousin, Pardo Suíço tipo carne e Simental) e as raças sintéticas Brangus (5/8 Angus + 3/8 Zebu) e Canchim (5/8 Charolês + 3/8 Zebu). Os grupos genéticos foram classificados de acordo com sua composição de taurino adaptado (Ta), taurino britânico (Tb), taurino continental (Tc) e zebuíno (Zb). Foram estimados os efeitos aditivos diretos e heteróticos individuais dos vários grupos de raças envolvidos e obtidas estimativas de herdabilidade e de correlação genética para as características. Os efeitos aditivos diretos de raças taurinas adaptadas, britânicas e continentais, em relação ao Nelore, bem como seus efeitos heteróticos individuais em combinação com a raça Nelore e entre si, sugerem a utilização dessas raças no sistema de produção em cruzamento com a raça Nelore. As estimativas de herdabilidade foram iguais a 0,53 ± 0,06; 0,39 ± 0,07; 0,57 ± 0,06; 0,31 ± 0,08; 0,57 ± 0,06; 0,51 ± 0,06; 0,37 ± 0,06; 0,59 ± 0,07; 0,09 ± 0,05; 0,43 ± 0,07; 0,29 ± 0,06 e 0,19 ± 0,07, para PFIN, TCON, GPD, CMS, PCF, RCF, EGAOL, AOL, FC, CRAC, pH e PPC, respectivamente, indicando a possibilidade de obtenção de progresso genético pela seleção para todas essas características, exceto FC. As correlações genéticas variaram de média a alta para PFIN com GPD (0,46), PCF (0,95) e FC (-0,60), GPD com PCF (0,59), RCF (0,57), AOL (0,34) e FC (-0,37), PCF com RCF (0,33), AOL (0,82) e FC (-0,80), RCF com AOL (0,52) e FC (-0,56), EGAOL com FC (-0,52) e AOL com FC (-0,38), indicando a possibilidade de resposta à seleção correlacionada para essas características.
Beef cattle carcass and meat quality are increasingly important for the productive sector, therefore studies with growth, carcass and meat traits of crossbred animals are fundamental, since crossbreeding allows to explore genetic differences among breeds to attend the aspects of product quality. The objectives of this study were to evaluate the viability of crossbreeding exotic breeds with the Nellore breed, through estimates of direct and heterotic individual effects, and the viability of selection in a crossbred population, through estimates of genetic parameters for weight at the end (PFIN; slaughter weight) of feedlot, daily weight gain in feedlot (GPD), feedlot time (TCON), daily dry matter consumption (CMS), cold carcass weight (PCF), cold carcass yield (RCF = PCF/PFIN), subcutaneous fat thickness (EGAOL), rib eye area (AOL), and the meat traits shear force (FC), water holding capacity (CRA), pH and cooking loss (PPC). Data on Nellore and Nellore crossbreds with adapted taurine breeds (Bonsmara and Senepol), British breeds (Angus and Hereford) and continental breeds (beef type Brown Suiss, Charolais, Limousin, and Simmental) and the synthetic breeds Brangus (5/8 Angus + 3/8 Zebu) and Canchim (5/8 Charolais + 3/8 Zebu) animals were used. The genetic groups were classified according to their composition of adapted taurine (Ta), British taurine (Tb), continental taurine (Tc) and zebu (Zb). The direct additive and heterotic individual effects of the various groups of breeds involved were estimated and heritability and genetic correlation estimates were obtained for the traits. The direct additive effects of adapted, British and continental taurine breeds, relative to Nellore, as well as their individual heterotic effects in combination with the Nellore breed and among themselves, suggest the use of these breeds in crossbreeding programs with the Nellore breed in the production system. The heritability estimates were equal to 0.53 ± 0.06, 0.39 ± 0.07, 0.57 ± 0.06, 0.31 ± 0.08; 0.57 ± 0.06, 0.51 ± 0.06, 0.37 ± 0.06, 0.59 ± 0.07, 0.09 ± 0.05, 0.43 ± 0.07, 0.29 ± 0.06 and 0.19 ± 0.07, for PFIN, TCONF, GPD, CMS, PCF, RCF, EGAOL, AOL, FC, CRA, pH and PPC, respectively, indicating the possibility of obtaining genetic progress by selecting for all these traits, except FC. The genetic correlations varied from medium to high for PFIN with GPD (0.46), PCF (0.95) and FC (-0.60), GPD with PCF (0.59), RCF (0.57), AOL (0.34) and FC (-0.37), PCF with RCF (0.33), AOL (0.82) and FC (-0.80), RCF with AOL (0.52) and FC (-0.56), EGAOL with FC (-0.52), and AOL with FC (-0.38), indicating the possibility of correlated response to selection for these traits. Other genetic correlations were of low magnitude.
Beef cattle carcass and meat quality are increasingly important for the productive sector, therefore studies with growth, carcass and meat traits of crossbred animals are fundamental, since crossbreeding allows to explore genetic differences among breeds to attend the aspects of product quality. The objectives of this study were to evaluate the viability of crossbreeding exotic breeds with the Nellore breed, through estimates of direct and heterotic individual effects, and the viability of selection in a crossbred population, through estimates of genetic parameters for weight at the end (PFIN; slaughter weight) of feedlot, daily weight gain in feedlot (GPD), feedlot time (TCON), daily dry matter consumption (CMS), cold carcass weight (PCF), cold carcass yield (RCF = PCF/PFIN), subcutaneous fat thickness (EGAOL), rib eye area (AOL), and the meat traits shear force (FC), water holding capacity (CRA), pH and cooking loss (PPC). Data on Nellore and Nellore crossbreds with adapted taurine breeds (Bonsmara and Senepol), British breeds (Angus and Hereford) and continental breeds (beef type Brown Suiss, Charolais, Limousin, and Simmental) and the synthetic breeds Brangus (5/8 Angus + 3/8 Zebu) and Canchim (5/8 Charolais + 3/8 Zebu) animals were used. The genetic groups were classified according to their composition of adapted taurine (Ta), British taurine (Tb), continental taurine (Tc) and zebu (Zb). The direct additive and heterotic individual effects of the various groups of breeds involved were estimated and heritability and genetic correlation estimates were obtained for the traits. The direct additive effects of adapted, British and continental taurine breeds, relative to Nellore, as well as their individual heterotic effects in combination with the Nellore breed and among themselves, suggest the use of these breeds in crossbreeding programs with the Nellore breed in the production system. The heritability estimates were equal to 0.53 ± 0.06, 0.39 ± 0.07, 0.57 ± 0.06, 0.31 ± 0.08; 0.57 ± 0.06, 0.51 ± 0.06, 0.37 ± 0.06, 0.59 ± 0.07, 0.09 ± 0.05, 0.43 ± 0.07, 0.29 ± 0.06 and 0.19 ± 0.07, for PFIN, TCONF, GPD, CMS, PCF, RCF, EGAOL, AOL, FC, CRA, pH and PPC, respectively, indicating the possibility of obtaining genetic progress by selecting for all these traits, except FC. The genetic correlations varied from medium to high for PFIN with GPD (0.46), PCF (0.95) and FC (-0.60), GPD with PCF (0.59), RCF (0.57), AOL (0.34) and FC (-0.37), PCF with RCF (0.33), AOL (0.82) and FC (-0.80), RCF with AOL (0.52) and FC (-0.56), EGAOL with FC (-0.52), and AOL with FC (-0.38), indicating the possibility of correlated response to selection for these traits. Other genetic correlations were of low magnitude.
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Palavras-chave
Correlações genéticas, Efeitos de raça, Efeitos heteróticos, Taurino, Zebuíno, Genética, Animais domésticos, Melhoramento genético