Growth and carcass characteristics of crossbred and straightbred Hereford steers. III. Post-weaning growth in seven environments in New South Wales

Abstract

Post-weaning growth, liveweight and body condition at slaughter were examined in 289 steers comprised of straightbred Hereford and first cross Brahman x Hereford, Simmental x Hereford and Friesian x Hereford. The steers were grown from weaning in seven environments throughout New South Wales. All steers were slaughtered when the average fat cover of the Herefords was in the range of 6-10 mm at the 12/13th rib. Brahman crossbreds were in similar body condition to Herefords at slaughter, which in turn were generally in better condition than both Simmental and Friesian crossbreds. Crossbred steers were heavier than Herefords at slaughter. Simmental crosses and Friesian crosses were 53 kg (12%) heavier on average over all environments, and Brahman crosses 41 kg (10%) and 83 kg (16%) heavier in inland and coastal environments respectively. Mean average daily gain (ADG) of the crossbred steers was always greater than that of the Hereford steers. There was a trend for ADG to be greater among the Brahman crosses earlier in the post-weaning period, but for the Simmental and Friesian crosses to grow faster later in the post-weaning period. Simmental crosses maintained a constant ADG advantage relative to Friesian crosses throughout the post-weaning period in environments where growth was favoured. Significant genotype x environment interactions occurred. Relative to Herefords, Simmental and Friesian crossbreds responded more to improved conditions, while Brahman crossbreds maintained a constant growth advantage regardless of environmental conditions. Bos taurus crosses grew faster than Brahman crosses, and Simmental crosses faster than Friesian crosses, only when environments were highly favourable.