Liveweight gain and carcass characteristics of bulls and steers farmed on hill country

Abstract

Liveweight gain and carcass and meat characteristics of Friesian bulls (n = 40) were compared with those of Hereford × Friesian bulls (n = 40) and Friesian × (Hereford × Angus) steers (n = 40). The cattle were grazed together on hill country from about 4 months, and were slaughtered either at c. 20 months (the heaviest animals at that time) or c. 28 months. Growth rates of the two bull groups were similar, and for both, were significantly higher than for the steer group. The Hereford-cross group of bulls had a higher dressing-out percentage (50.0) than either of the other groups (49.0), and their carcasses were 3.5% shorter than those of the Friesian bulls at the same weight. Kidney and pelvic fat weight and percentage intramuscular fat were similar for the two bull groups, but fat depth was greater for the Hereford-cross bulls. All measures of fatness were significantly greater for the steer group, but their mean rib-eye area was less than for the Hereford-cross bulls (63.2 versus 69.7 cm2). Beef from bulls had a higher mean ultimate pH (6.11 versus 5.64), and an associated darker colour and shorter sarcomere lengths. After adjustment to a constant pH, these differences were no longer apparent, but bull beef had a higher pH-adjusted cooking loss (27.1 versus 24.5%). The results were consistent with the suggestion that the increased shear force associated with an increase in ultimate pH from 5.5 to about 6.2 resulted in part from some muscle contraction. Meat from the 28-month group had higher Warner-Bratzler shear values and a darker colour after adjustment for differences in pH. © 1995 Taylor & Francis Group, LLC.