Estimating genetic covariance functions assuming a parametric correlation structure for environmental effects

Estimates of genetic covariance functions assuming a parametric correlation structure for environmental effects

A random regression model for the analysis of ‘repeated’ records in animal breeding is described which combines a random regression approach for additive genetic and other random effects with the assumption of a parametric correlation structure for within animal covariances. Both stationary and non-stationary correlation models involving a small number of parameters are considered. Heterogeneit...

Estimates of Genetic Covariance Functions for Growth of Nelore Cattle Assuming a Parametric Correlation Structure for Animal Permanent Environmental Effects

INTRODUCTION Random regressions (RR) on Legendre polynomial (LP) of age have been used to model longitudinal data such as milk production and weights at different ages. Usually such models involve high degree polynomials, especially for direct permanent environmental effects and, consequently, a large number of parameters to be estimated. High order polynomials are associated with sampling prob...

Methods for Estimating Heterogeneous Spatial Covariance Functions with Environmental Applications

Estimation of spatial covariance is important to many statistical problems in the analysis of environmental monitoring data. In this Chapter we review several difrerent methods for spati.al covariance estimation from monitoring data, with emphasis on methods for heterogeneous models. We briefly describe some applications, and outline how these methods can be extended to space-time and multivari...

Estimating the covariance structure for environmental effects in weaning weight of beef cattle

Estimates of covariance functions for growth of Nelore cattle applying a parametric correlation structure to model within-animal correlations

A total of 20,065 weights recorded on 3016 Nelore animals were used to estimate covariance functions for growth from birth to 630 days of age, assuming a parametric correlation structure to model within-animal correlations. The model of analysis included fixed effects of contemporary groups and age of dam as quadratic covariable. Mean trends were taken into account by a cubic regression on orth...