Estimating the covariance structure for environmental effects in weaning weight of beef cattle
نویسنده
چکیده
منابع مشابه
Symmetric differences squared and analysis of variance procedures for estimating genetic and environmental variances and covariances for beef cattle weaning weight: I. Comparison via simulation.
Analysis of variance (ANOVA) and symmetric differences squared (SDS) methods for estimating genetic and environmental variances and covariances associated with beef cattle weaning weight were compared via simulation. Simulation was based on the pedigree and record structure of 503 beef weaning weights collected over 19 yr from a university herd. The SDS methodology was used with four models. Th...
متن کاملRunning head : REGRESSION ON MATERNAL PHENOTYPE Estimates of genetic parameters for weaning weight of beef cattle accounting for direct-maternal environmental covariances
Restricted Maximum Likelihood algorithm estimates of (co)variance components due to maternal effects as well as a regression on maternal phenotype were obtained for seven weaning weight data sets of Australian and New Zealand beef cattle. Fitting such regression, analyses accounted for environmental covariances between dams and their offspring. Results show a substantial, negative regression on...
متن کاملRunning head : Maternal Variances for Growth of Beef Cattle Variance Components due to Direct and Maternal Effects for Growth Traits of Australian Beef Cattle
Variance components for birth, weaning, yearling and final weight in Australian Hereford, Angus and Zebu Cross cattle were estimated by Restricted Maximum Likelihood. Six different animal models were fitted for each trait and breed, ranging from a simple model with animals as the only random effect to the most comprehensive model allowing for both genetic and environmental maternal effects and ...
متن کاملGenetic parameters for growth traits of Australian beef cattle from a multibreed selection experiment.
Estimates of covariance components and genetic parameters were obtained for birth, weaning, 200-d, and 400-d weight for a herd of Polled Herefords and a herd of a multibreed synthetics, the so-called Wokalups. Data originated from an experiment in Western Australia selecting for preweaning growth rate. Analyses were carried out by REML fitting an animal model including genetic and permanent env...
متن کاملEstimates of genetic covariance functions for growth of Australian Angus cattle from random regression models fitting different orders of polynomials
INTRODUCTION Random regression (RR) analyses have been suggested for the analysis of growth records for beef cattle. A previous analysis of a large set of field data fitted cubic regressions on age at recording for all random effects, i.e. direct and maternal, genetic and permanent environmental effects (Meyer, 2002a). This choice was determined by the fact that a cubic polynomial is the lowest...
متن کامل