Live weight traits are economically important for beef cattle production systems. Genetic analysis of live weight traits frequently presents a problem due to animal records, in that matter, not all the animals have complete records as many young animals leave the herd because of sale, transfer to another herd, or culling reasons. Therefore, the use of multi-trait genetic analysis might be of assistance to help overcome any possible loss of information for those animals with incomplete records. In this study, genetic variances and covariances were obtained to estimate genetic parameters for birth (BW), weaning (WW), and yearling (YW) live weights in a registered Charolais beef cattle population using a multivariate model, where a considerable reduction of data from birth weight to year weight was observed. Direct and maternal heritabilities for BW, WW, and YW were 0.50, 0.30, and 0.28, and 0.31, 0.25, and 0.14, respectively. Direct and maternal genetic correlations were negative in all live weight traits. Genetic correlations among direct BW with direct WW and YW were low, while genetic correlations among maternal traits were medium or high (r>0.39). Comparison between univariate and multi-trait models with substantial reduction of information revealed important differences, implying that multi-trait analysis is better for the structure of data allowing a better fitting of genetic effects by covariance among evaluated traits. Results support multi-trait analysis implementation for genetic evaluations for live weight traits of Charolais cattle.

中文翻译：

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夏洛莱牛活体重性状的遗传变异和协方差的多特征分析。

活重性状对于肉牛生产系统在经济上很重要。活体重性状的遗传分析经常由于动物记录而出现问题，因为并不是所有的动物都有完整的记录，因为许多年幼的动物由于出售，转移到另一畜群或淘汰原因而离开了畜群。因此，多特征基因分析的使用可能有助于克服记录不完整的那些动物可能丢失的任何信息。在这项研究中，获得了遗传方差和协方差，使用多变量模型估算了已注册的夏洛来牛肉牛的出生体重（BW），断奶体重（WW）和一岁体重（YW）的遗传参数，其中数据大大减少了。从出生体重到年体重。BW的直接和母体遗传，WW和YW分别为0.50、0.30和0.28，以及0.31、0.25和0.14。所有活体重性状的直接和母亲遗传相关性均为负。直接体重与直接WW和YW之间的遗传相关性较低，而孕产妇性状之间的遗传相关为中等或较高（r > 0.39）。单变量模型和多特征模型之间的比较，信息量大大减少，这表明存在重要差异，这意味着多特征分析更适合数据结构，从而可以通过评估性状之间的协方差更好地拟合遗传效应。结果支持多性状分析实施对夏洛来牛活体重性状的遗传评估。