Estimates of direct, maternal and grandmaternal genetic effects for growth traits in Gobra cattle

Abstract

Estimates of genetic parameters for birth (N = 3909), weaning (N = 3425), yearling (N = 2764) and final (N = 2144) weights were obtained from the records of Gobra cattle collected at the Centre de Recherches Zootechniques de Dahra, Senegal. Three animal models were fitted to obtain estimates by REML using an average information (AI) approach. Model 1 considered random direct, maternal genetic and maternal permanent environmental effects. In model 2, a general grandmaternal effect was added to the random effects considered in model 1, and in model 3, the general grandmaternal effect was divided into grandmaternal genetic and grandmaternal permanent environmental effects. All models allowed covariances among genetic effects. The inclusion of grandmaternal effects in models 2 and 3 did not change the estimates of the genetic parameters compared to model 1. Variances attributable to grandmaternal effects became negative and were set close to zero, except for yearling weight for which grandmaternal heritability was 0.03 ± 0.03. The estimates for direct and maternal heritabilities were, respectively, 0.08 ± 0.03 and 0.03 ± 0.02 for birth, 0.20 ± 0.05 and 0.21 ± 0.05 for weaning, 0.26 ± 0.07 and 0.16 ± 0.07 for yearling and 0.14 ± 0.06 and 0.16 ± 0.06 for final weights. The estimates of the genetic correlation between direct and maternal effects for birth, weaning, yearling and final weights were -0.17 ± 0.40, -0.58 ± 0.32, -0.52 ± 0.34 and -0.34 ± 0.37, respectively. For yearling weight with grandmaternal heritability estimated to be only 0.03, model 3 gave estimates of the genetic correlation between direct and grandmaternal effects and between maternal and grandmaternal effects of 0.28 ± 0.48 and -0.33 ± 0.67, respectively. Estimates of direct and maternal heritabilities were unchanged when grandmaternal effects were not included in the model.<br>Foram obtidas as estimativas dos pesos ao nascimento (N = 3909), ao desmame (N = 3425), com 1 ano de idade (N = 2764) e final (N = 2144) a partir dos registros de gado Gobra coletados no Centro de Pesquisas em Zootecnia de Dahra, Senegal. Três modelos animais foram adaptados para obter estimativas por REML usando uma abordagem de informação média (AI). O modelo 1 considerou os efeitos ambientais aleatórios direto, genético maternal e maternal permanente. No modelo 2, um efeito geral relativo às avós foi adicionado aos efeitos aleatórios considerados no modelo 1, e no modelo 3 o efeito geral relativo às avós foi dividido em efeitos ambientais genético e permanente. Todos os modelos admitiram covariâncias entre os efeitos genéticos. A inclusão dos efeitos relativos às avós nos modelos 2 e 3 não alterou as estimativas dos parâmetros genéticos comparados com o modelo 1. As variâncias atribuíveis aos efeitos relativos às avós tornaram-se negativas e foram posicionadas próximas a zero, exceto para o peso com 1 ano, para o qual a herdabilidade relativa à avo foi 0,03 ± 0,03. As estimativas para as herdabilidades direta e maternal foram, respectivamente, 0,08 ± 0,03 e 0,03 ± 0,02 pa...

Genetic parameters and predictions for direct and maternal growth traits in a multibreed Angus–Brahman cattle population using genomic–polygenic and polygenic models

“…In addition, the similarity between variance components and genetic parameters from the polygenic model and genomic-polygenic model 2 indicated that genotypic and pedigree information from genotyped animals accounted for additive genetic (co)variability for growth traits to a similar extent. Estimates of variance components and genetic parameters for growth traits here were within the range of values obtained for B. taurus (Garrick et al, 1989;Meyer, 1992Meyer, , 1994Van Vleck et al, 1996;Dodenhoff et al, 1998;Elzo et al, , 2001Montaldo and Kinghorn, 2003;Szabó et al, 2012)), Bos indicus (Eler et al, 1995;Diop et al, 1999;Elzo et al, , 2001Montaldo and Kinghorn, 2003), and B. taurus  B. indicus cattle (Meyer, 1992;Elzo et al, , 2001Demeke et al, 2003;Vergara et al, 2009).…”

Efeitos Da Inclusão Ou Não Da Covariância Genética Direta-Maternal No Modelo E Dos Valores Reais Das (Co)variâncias Sobre Suas Estimativas Para Peso À Desmama Em Bovinos De Corte

“…MEYER (1992) estimou (co)variâncias para pesos à desmama, em bovinos Hereford, Angus e Zebu cruzado na Austrália, através de seis diferentes modelos, verificando que, quando os efeitos maternais foram ignorados, a herdabilidade direta foi inflada substancialmente. DIOP et al (1999) testaram a inclusão dos efeitos de avós no modelo animal com efeitos maternos em animais da raça Gobra, no Senegal, e sugeriram que o valor negativo da correlação genética entre os efeitos direto e materno podia estar relacionado com as condições ambientais em que os animais foram manejados.…”

Genotype-environment interaction, genetic trends, and performance dissimilarity of Nellore herds raised in three different environmental gradients

“…However, this estimate may be biased due to the evaluation through the arrangement of the proposed model. Diop et al (1999) inserted the effects of granddam into the model (animal model) with maternal effects, and stated that the negative genetic correlation between the direct and maternal effects could be related to the environmental conditions in which the animals were managed. Meyer (1992), Souza et al (1998), Fernandes and Ferreira (2000), Carvalho et al (2013), Lacerda et al (2014) and Santos et al (2012) evaluated beef cattle using field data and found also negative genetic correlations between direct and maternal effects.…”