Herbage intake, growth performance, and carcass and meat quality characteristics of once-bred Hereford × Friesian heifers weaned at 12 or 21 weeks of lactation

Abstract

Beef-breeding cows are traditionally weaned at about 7-8 months of calf age in New Zealand but early weaning may have advantages in once-bred heifer beef production systems. This study compared the growth performance, and carcass and meat quality characteristics, of 31 once-bred Hereford × Friesian heifers mated to Angus (17 heifers) or Charolais (14 heifers) sires from which calves were removed at either 12 weeks (Day 84 of lactation = L84) or 21 weeks (Day 147 of lactation = L147) of lactation. These are referred to as the “W84” (calves weaned at Day 84 and their dams) or “W147” (calves weaned at Day 147 and their dams) groups respectively. During L84-L147, W84 heifers had higher daily liveweight gain (LWG) than the W147 heifers (0.79 versus 0.51, PSE = 0.07 kg/day, P < 0.01). Calves weaned at L84 had significantly lower daily LWG than W147 calves during the period L84-L147 (0.73 versus 1.30, PSE = 0.05 kg/day, P < 0.001). This resulted in 30 kg lower (P < 0.001) liveweight in W84 versus W147 calves at the time of weaning for the latter group. During the period L137-L147, the W84 versus W147 heifers had herbage organic matter intakes (estimated using intraruminal chromium controlled-release capsules) of 3.01 versus 3.50 (PSE = 0.16) kg DM/100 kg LW per day (P < 0.05). Heifers whose calves were removed at L147 spent more time grazing (P < 0.01) and ruminating (P < 0.10), and less time idling (P < 0.01) than the W84 heifers. Overall, weaning time did not significantly affect the carcass and meat quality characteristics of W84 or W147 heifers. Results are discussed in the context of weaning time effects on the productivity and carcass and meat quality traits of once-bred heifers. © 1995 Taylor & Francis Group, LLC.