OBJECTIVE This study was conducted to estimate breed-specific variance components for total number born (TNB), number born alive (NBA) and mortality rate from birth through weaning including stillbirths (MORT) of three main swine breeds in Korea. In addition, the importance of including maternal genetic and service sire effects in estimation models was evaluated. METHODS Records of farrowing ...

INTRODUCTION Random regression (RR) models for longitudinal data often require a considerable number of parameters to describe the associated covariance functions. Estimation of these parameters has proven cumbersome and subject to sampling problems. Moreover, computational restraints have limited analyses of data sets sufficiently large to supply accurate estimates. This holds especially for c...

Rules for forming the mixed-model equations for the reduced animal model with all relationships and including maternal effects have been set out by Quaas and Pollak. They also have shown how to simplify the mixed-model equations when genetic group effects are included in the model with what has become known as the Q-P transformation. Westell has given rules for calculating the coefficients for ...

Simulation and calculations based on the likelihood function are used to examine the sampling properties of maximum likelihood estimates of variance components due to sex-linked, maternal and dominance effects. Data are assumed to have been collected in an experiment designed specifically to provide a sufficient set of covariances between relatives for this task. Results show that variances due...

Statistical models (16) were compared for birth weight of 24,741 Columbia lambs recorded at the U.S. Sheep Experiment Station (USSES; 1950 to 1998). The goal was to estimate fractions of variance due to cytoplasmic line (c2; n = 590) and sire x cytoplasmic line interaction (sc2; n = 12,831) with other nuclear and environmental effects included in the model. The basic model included direct genet...