Chronological age and dentition effects on carcass and meat quality of cattle in northern Australia

Abstract

The effects of chronological age and dentition on the liveweight, carcass weight, bruising and muscle properties of 348 cows and 370 steers were examined in 5 experiments in Queensland (1982-83). Birth dates were known only for the cows in experiments 1 and 2, and for the steers in experiment 5; with ages categorised as 4 years and less (young), 5-10 years (mature) and greater than 10 years (old). The number of permanent 'incisor' teeth were recorded for all animals. The cattle were weighed (unfasted), transported to an abattoir and given access to water and hay (except in experiment 5). Mustering to slaughter periods varied from 2 to 7 days. Half the carcasses were electrically stimulated in experiments 1 and 2. In general, old and mature cows with 8 teeth had heavier (P<0.05) mean liveweights than did young cows with 4 teeth, and both had heavier (P<0.05) liveweights and carcass weights than those with 2 teeth. Old cows with 8 teeth also had the lowest (P<0.05) mean dressing percentage, while mature cows had the greatest (P<0.05) fat depth. There was no consistent trend between groups in bruise score. Steers with 8 teeth had a greater (P<0.05) mean liveweight, carcass weight, dressing percentage and rib fat depth than other dentition groups, and a greater (P<0.05) bruise score in experiment 5 only. There was no significant effect of chronological age or dentition on the shear force values or cooking losses of M. longissimus dorsi (LD) for cows. In 1 experiment, steers with 8 teeth had a greater (P<0.05) peak force-initial yield value and lower (P<0.05) cooking loss than other dentition groups. Mature cow carcasses cooled more (P<0.05) slowly than those of other ages. Over all experiments, there were more (P<0.05) high pHz4 carcasses among the combined 6 and 8 teeth group than the combined 2 and 4 teeth group (10.2 v. 2.3%).