Heritable maternal effects have important consequences for the evolutionary dynamics of phenotypic traits under selection, but have only rarely been tested for or quantified in evolutionary studies. Here we estimate maternal effects on early-life traits in a feral population of Soay sheep (Ovis aries) from St Kilda, Scotland. We then partition the maternal effects into genetic and environmental...

the genetic parameters and (co) variance components of body weight at birth (bw), weaning (ww) and six months of age (bw6) and average daily gain (adg) pre and post-weaning of afshari sheep were estimated using restricted maximum likelihood (reml) methodology and animal model implemented in dfreml software. the likelihood ratio test (lrt) was used to compare the models. year of birth, age of mo...

The genetic parameters and (co) variance components of body weight at birth (BW), weaning (WW) and six months of age (BW6) and average daily gain (ADG) pre and post-weaning of Afshari sheep were estimated using restricted maximum likelihood (REML) methodology and animal model implemented in DFREML software. The likelihood ratio test (LRT) was used to compare the models. Year of birth, age of mo...

An experiment involving crosses among selection and control lines was conducted to partition direct and maternal additive genetic response to 20 yr of selection for 1) weaning weight (WWL), 2) yearling weight (YWL), and 3) an index of yearling weight and muscle score (IXL). Maternal response was estimated from reciprocal crosses among unselected sires and dams of control (CTL) and the selection...

Heritabilities of and genetic correlations between additive direct and maternal genetic effects for calf market weight, and additive direct genetic effects for carcass traits, were estimated for Japanese Black cattle by REML procedures under 2-trait animal models. Data were collected from calf and carcass markets in Hyogo and Tottori prefectures and analyzed separately by prefecture. Calf marke...

Dominance and additive x additive genetic variances were estimated for birth and weaning traits of calves from three synthetic lines of beef cattle differing in mature size. Data consisted of 3,992 and 2,877 records from lines of small-, medium-, and large-framed calves in each of two research herds located at Rhodes and McNay, IA, respectively. Variance components were estimated separately by ...

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 ...

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 ...

Estimates of covariance components were obtained for milk production of beef cows, measured by the weigh-suckle-weigh method, and weaning weight and preweaning growth of their calves for a herd of Polled Herefords and a herd of a multibreed synthetics, so-called Wokalups. Analyses were carried out by restricted maximum likelihood fitting an animal model incorporating both direct and maternal ge...

Optimum weighting ratios of maternal:direct EBV for litter size using an animal model were examined to achieve maximum genetic improvement (direct plus maternal response). Stochastic simulation of a 120-sow herd over a 10-yr period of selection was used (20 replicates). Directional selection was based on a merit function of maternal and direct EBV for first-parity litter size. Optimum weighting...