Weaning Age of Angus Heifer Calves as a Factor Influencing Calf and Cow Performance

Abstract

Effects of weaning calves at 120 and 210 days of age on pre-weaning, post-weaning, reproductive and progeny performance were studied over 6 years in a herd of purebred Angus cattle. There were 895 calves of both sexes in the pre-weaning study with 443 weaned at 120 days of age and placed on self-feed and bluegrass pasture to 210 days of age, while 452 nursed their dams to 210 days of age with no supplemental feed. Post-weaning performance is reported on 458 heifer calves. Reproductive and progeny performance data were recorded and analyzed on 699 parturitions by the 199 heifers selected as herd replacements. Early weaned (120 days) calves exceeded late weaned calves by .18 points conformation score and 10.1 kg 210-day adjusted weight. Late weaned (210 days) heifers gained 11 kg more than early weaned heifers in the post-weaning period which resulted in virtually equal yearling weights for the two weaning age groups. Weaning age of the cow when she was a calf did not affect either her reproductive efficiency or birth weight, 120-day ratio and 210-day ratio of her progeny. Dams of early weaned calves gained 12 kg more than dams of late weaned calves between 120 and 210 days post-partum. This weight gain was mildly associated with greater percentages pregnant and live calves, with earlier calving and with increased calving difficulty the following year. Considering all traits, both systems of weaning (120 days or 210 days) produced similar and satisfactory results. The decision concerning age of weaning can be based largely on management factors.