Phenotypic evaluation of pre-weaning growth traits of Akaushi- (Wagyu), Angus- and Brahman-sired calves in tropical conditions

Abstract

The objective was to assess the effect of sire breed on birth weight, average daily gain from birth to weaning, and actual weaning weight of calves. The calves were produced by AI using semen of five Akaushi (Wagyu), six Angus, and six Brahman bulls. Dams of calves were Beefmaster (n = 60) and Brown Swiss x Zebu (n = 21). The three sire breeds were used on both dam genetic types to produce the calves (45 males and 36 females). Each dam genetic type was raised in two ranches; therefore, all calves were born in four ranches, in the same calendar year. Average age at weaning weight m easurement was 186days. The traits were analyzed with the MIXED procedure of SAS. The statistical model included the fixed effects of sire breed, dam genetic type, calf sex, ranch, and birth season within sire breed-ranch; sire within breed of sire was included as a random effect (except for weaning weight; P > 0.05). In addition, the model for weaning weight included calf age at weaning as a covariate. Birth weights and average daily gains of Akaushi-, Angus- and Brahman-sired calves were similar (P > 0.05). In contrast, Angus-sired calves were heavier (P < 0.05) at weaning than Akaushi- and Brahman-sired calves. Calves out of Brown Swiss x Zebu dams had higher (P < 0.05) pre-weaning average daily gains than calves out of Beefmaster dams. Angus-sired calves performed better at weaning.