期刊文献

Simultaneous Bayesian estimation of genetic parameters for curves of weight, feed intake, and residual feed intake in beef cattle 收藏

同时对牛肉牛的重量,进料摄入曲线和残留饲料摄入曲线的遗传参数估计
摘要
Rates of gain and feed efficiency are important traits in most breeding programs for growing farm animals. The rate of gain (GAIN) is usually expressed over a certain age period and feed efficiency is often expressed as residual feed intake (RFI), defined as observed feed intake (FI) minus expected feed intake based on live weight (WGT) and GAIN. However, the basic traits recorded are always WGT and FI and other traits are derived from these basic records. The aim of this study was to develop a procedure for simultaneous analysis of the basic records and then derive linear traits related to feed efficiency without retorting to any approximation. A bivariate longitudinal random regression model was employed on 13,791 individual longitudinal records of WGT and FI from 2,827 bulls of six different beef breeds tested for their own performance in the period from 7 to 13 mo of age. Genetic and permanent environmental covariance functions for curves of WGT and FI were estimated using Gibbs sampling. Genetic and permanent covariance functions for curves of GAIN were estimated from the first derivative of the function for WGT and finally the covariance functions were extended to curves for RFI, based on the conditional distribution of FI given WGT and GAIN. Furthermore, the covariance functions were extended to include GAIN and RFI defined over different periods of the performance test. These periods included the whole test period as normally used when predicting breeding values for GAIN and RFI for beef bulls. Based on the presented method, breeding values and genetic parameters for derived traits such as GAIN and RFI defined longitudinally or integrated over (parts of) of the test period can be obtained from a joint analysis of the basic records. The resulting covariance functions for WGT, FI, GAIN, and RFI are usually singular but the method presented here does not suffer from the estimation problems associated with defining these traits individually before the genetic analysis. All the results are thus estimated simultaneously, and the set of parameters is consistent.
摘要译文
在大多数种植农场动物的育种计划中,获取和饲料效率的速度是重要的特征。收益率(增益)通常在一定年龄的时间内表示,而饲料效率通常表示为残留饲料摄入量(RFI),定义为观察到的饲料摄入量(FI)减去基于活体重(WGT)的预期进料摄入量和增益。但是,记录的基本特征始终是WGT,FI和其他特征源自这些基本记录。这项研究的目的是制定一种同时分析基本记录的程序,然后得出与饲料效率相关的线性特征,而无需反驳任何近似值。从2,827名公牛的六个不同的牛肉品种的纵向记录中采用了13,791个单个WGT和FI的单个纵向记录,该模型采用了双变量纵向随机回归模型,该模型在7至13个月中的六个不同牛肉品种的六种不同牛肉品种。使用GIBBS采样估算了WGT和FI曲线的遗传和永久环境协方差函数。根据FI给定的WGT和增益的条件分布,从WGT函数的第一个衍生物中估算了增益曲线的遗传和永久协方差函数,最后将协方差函数扩展到RFI的曲线。此外,扩展了协方差函数,包括在性能测试的不同时期内定义的增益和RFI。这些时期包括通常在预测牛肉收益和RFI的繁殖值时通常使用的整个测试期。基于提出的方法,可以从基本记录的联合分析中获得纵向定义的衍生性状和诸如增益和RFI诸如增益和RFI定义或整合(部分)(部分)的繁殖值和遗传参数。WGT,FI,增益和RFI的结果协方差函数通常是单数的,但此处介绍的方法并不遭受与遗传分析之前单独定义这些性状相关的估计问题。因此,所有结果都是同时估计的,并且参数集是一致的。
Hadi Esfandyari; Just Jensen. Simultaneous Bayesian estimation of genetic parameters for curves of weight, feed intake, and residual feed intake in beef cattle[J]. Journal of Animal Science, 2021,99(9)