SOURCES OF VARIATION IN BEEF CATTLE WEANING WEIGHT

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...

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

Age-of-dam adjustment factors for birth and weaning weight records of beef cattle: a review.

Age-of-dam adjustment factors are used to preadjust birth and weaning weight data for national beef cattle genetic evaluations. Adjustments are used in order to make the means of the different age-of-dam subclasses similar so that a fair comparison of animals can be performed. A review was made of various research studies that have estimated age-of-dam adjustment factors for birth weight and we...

Weaning Strategies in Beef Cattle to Reduce Stress

Weaning is considered one of the most stressful periods in the beef production system for beef calves. During this process calves are subjected to a variety of stressors including removal from their mothers, new diets, processing (vaccination, dehorning, castration etc.), and possibly even new pen or pasture environments. These stressors, singly or in combination, can result in behavior or phys...