Effects of season of birth, breed of sire and sex of calf in a single-suckled Aberdeen Angus Holstein beef herd

Abstract

ABSTRACTData were obtained from 233 heifers and 246 steers born in the autumn (September) or spring (March) seasons. The calves were sired by Polled Hereford (British) and Charolais, Chianina, Limousin. Maine- Anjou and Simmental (Continental European) bulls, from Aberdeen Angus (♂ × Holstein ♀ cows. Autumn-born calves weighed more at birth than did spring-born calves ( P < 0·01 ). Season of birth did not affect 205-. 305-. 365-day or slaughter weights. Incidence of dystocia was greater for Maine-Anjousired calves than for Polled Hereford calves (P < 0·05) with the other breeds intermediate. Significant sex differences were observed in practically all live and carcass traits with the exception of Warner- Bratzler tenderness and taste panel evaluations.There were significant breed effects in which Continental European-sired calves gained weight more rapidly than did Polled Hereford-sired calves (P < 0·01) within each 90-day period, with the exception of 180 to 270 days. Slaughter weight and carcass weight per day of age followed the same trend. At slaughter at a mean age of 416 days, mean live weight of calves from Continental European breeds of sire was 1·075 of that of the Polled Hereford-sired calves. Proportion, weight and gain per day of edible meat in the carcass were greater for calves sired by Continental European bulls (P < 0·01). Although fat thickness and marbling score means were greater for Polled Hereford-sired cattle (P < 0·01), there were no significant differences in taste panel evaluations. There were no important two-way interactions between the main effects (sex, season of birth or sire breed).