Carcass weights of cattle in relation to breed, sex, age, region of origin and season

Abstract

Effects on carcass weights of region of origin, season and year of slaughter, breed, sex, age and pregnancy status were examined for 4229 cattle slaughtered in selected Australian abattoirs in 1973 and 5708 cattle in 1977-78. For non-pregnant cows slaughtered in 1973, the relationship between carcass weight and presence of cyclic activity of the ovaries was examined at slaughter. Data from abattoirs in Rockhampton, Mackay and Townsville are also presented on carcass weights of about 641 000 cattle killed from January 1977 to November 1979. In 1977-78, at abattoirs in northern, central and eastern Australia, carcass weights of slaughtered bulls averaged 269 kg, steers 263 kg and cows 188 kg, compared with mean carcass weights of 263, 276 and 186 kg for all bulls, steers and cows killed in 3 northern Queensland abattoirs during 1977-79. Cows slaughtered in north-eastern Australian abattoirs in 1973 averaged 160 kg. After adjusting for breed, sex and age differences, carcass weights of cattle slaughtered in 1977-78 differed by region of origin, with greater weights from subtropical than from northern tropical and coastal regions; and by season of slaughter, with lowest weights being recorded in spring. Carcass weights of cows from tropical regions and slaughtered in 1973 increased by 10 kg (British breed), 32 kg (Brahman) and 69 kg (British x Brahman), as age increased from 2 to 5 years. With increased age beyond 5 years, carcass weights of these cows decreased. Conversely, carcass weights of British breed cows reared in subtropical regions and slaughtered in 1977 increased by 37 kg throughout the 2-12 year age range. After adjusting for breed, age, season and regional differences, mean carcass weights of non-pregnant, cycling cows and cows grouped according to trimester of pregnancy were not different. Carcass weights of cows which were non-pregnant and non-cycling were 12 kg less than cows which were non-pregnant but cycling. Cycling prevalence in Brahman cows exceeded those of British breed or British x Brahman cows from northeastern Australia, when compared at the same age and carcass weight. Age had no effect on cycling prevalence when cows were compared at the same carcass weight.