Multicollinearity in genetic effects for weaning weight in a beef cattle composite population

Sire x herd interactions for weaning weight in beef cattle.

Weaning weight records of 44,357 Australian Angus calves produced by 1,020 sires in 90 herds were used to evaluate the importance of sire x herd interactions. Models fitted fixed effects of contemporary group (herd-year-date of weighing subclass), sex, calf age, and dam age and random effects of sire or of sire and sire x herd interaction using REML. Effects of standardizing the data, including...

Pre-weaning growth traits of the Hereford breed in a multibreed composite beef cattle population

Data from a multibreed composite beef cattle population, managed under intensive irrigated grazing conditions, were used to estimate direct additive heritabilities (ha), maternal heritabilities (h 2 m) and maternal permanent environmental effects (c) for birth weight (BW) and weaning weight (WW) of the calf and cow efficiency of the dam (CE: WW/dam weight x 100). Calves born between 1968 and 19...

Estimation of genetic effects in the presence of multicollinearity in multibreed beef cattle evaluation.

Breed additive, dominance, and epistatic loss effects are of concern in the genetic evaluation of a multibreed population. Multiple regression equations used for fitting these effects may show a high degree of multicollinearity among predictor variables. Typically, when strong linear relationships exist, the regression coefficients have large SE and are sensitive to changes in the data file and...

The Influence of Breed Composition on Weaning Weight Parameters in a Multibreed Beef Cattle Population

Direct and maternal components were estimated for birth weight and weaning weight in a multibreed cattle population. Data consisted of 20840 records of calves with varying levels of British (B), Charolais (C), Simmental (S) and Afrikaner (A) breeds. It included several F1, backcrosses, threebreed and fourbreed crosses, having an approximate average composition of /8B : /8S : /8C : /8A. The numb...

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