Faculdade de Ciências Agrárias e Veterinárias (FCAV), Universidade Estadual Paulista, Jaboticabal, São Paulo 14884-900, Brasil.
Facultad de Ciencias Agrarias, Fundación Universitaria Agraria de Colombia-UNIAGRARIA, Bogotá 111166, Colombia.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad150.
Evaluating traits that allow breeders to increase production efficiency in beef production systems is important. The mouth size (MS) score is a trait easily measured and implemented by breeders. Bite size is related to MS in beef cattle and is a determinant of daily feed intake of pasture-raised animals, influencing their growth. The aim of this study was to estimate genetic parameters for MS, weaning weight (WW) and postweaning weight gain (PWG) of Nelore cattle and to evaluate the influence of the interaction between MS and WW on PWG. Phenotypic records of 134,282 Nelore animals born between 1995 and 2019 were used. Variance components were estimated using multitrait animal model with the Bayesian method. The model included the contemporary group as fixed effect, age at measurement of the trait as linear covariate, and direct additive genetic and residual effects as random effects. For WW, random maternal and maternal permanent environmental effects were added to the model. A Bayesian approach was used to analyze the interaction between WW clusters and MS. The heritability estimates were 0.24, 0.15, and 0.23 for MS, WW, and PWG, respectively. The genetic correlation between variables studied ranged from 0.24 to 0.46. The results suggest that animals with a larger mouth tend to have greater PWG, demonstrating the positive influence of MS score on the postweaning performance of cattle. The direct heritability estimates confirm the possibility of selecting animals for the traits studied.
评估能够提高肉牛生产系统生产效率的特性非常重要。嘴型（MS）评分是一个易于测量和实施的特性。在肉牛中，咬合力与 MS 有关，是影响放牧动物日采食量的决定因素，从而影响其生长。本研究的目的是估计 MS、断奶重（WW）和断奶后体重增加（PWG）的遗传参数，并评估 MS 与 WW 之间的互作对 PWG 的影响。使用了 1995 年至 2019 年间出生的 134,282 头 Nelore 动物的表型记录。使用多性状动物模型和贝叶斯方法估计方差分量。该模型包括当代群体作为固定效应、性状测量时的年龄作为线性协变量，以及直接加性遗传和残余效应作为随机效应。对于 WW，随机母体和母体永久环境效应被添加到模型中。采用贝叶斯方法分析 WW 群与 MS 之间的相互作用。MS、WW 和 PWG 的遗传力估计值分别为 0.24、0.15 和 0.23。研究变量之间的遗传相关性在 0.24 到 0.46 之间。结果表明，嘴型较大的动物往往具有更大的 PWG，这表明 MS 评分对牛的断奶后表现有积极影响。直接遗传力估计值证实了对所研究性状进行选择的可能性。
