Effect of Time of Weaning on Performance of Young and Mature Beef Cows and Their Calves in a Fall Calving System

Time of weaning influenced cow body weight and body condition score. At the beginning of the calving season, NW cows were heavier and had greater fat reserves than LW cows. Postpartum BW and BCS loss was significantly greater for NW cows, resulting in similar BW and BCS at the beginning of the breeding season and until April. Progeny of NW cows were 2.3 kg heavier at birth and grew faster prior to weaning, resulting in increased weights (+ 10 kg) at the time of normal weaning. When considering all calves weaned on the trial, late weaning increased calf weights in July, regardless if NW calves were retained during the summer. These findings indicate that producers may benefit from matching weaning date to cow age class. It appears more advantageous to delay weaning of calves born to dams 4 yr or older, while maintaining normal weaning for dams 3 yr or younger at time of calving. Late- weaning had no detrimental effects for mature cows indicating this practice appears to be a viable alternative weaning options.