101 Impact of weaning strategy on beef cow and calf weight and body condition

Abstract Weaning is one of the largest stressors in an animal’s life and can have long term impacts on the animal. The objective of this study was to investigate the effect of weaning strategy on the weight and body condition of beef cattle. A total of 249 Angus-based pairs at two locations were assigned to one of three treatments: abrupt removal of the calf on d0 (Abrupt, n = 84), fenceline contact for 7 days followed by complete separation on d7 (Fence, n = 85), or late weaning d84 (Late, n = 80). Weaned calves were supplemented 0.23 kg/hd/d of grain as fed while Late were not supplemented. Weights were obtained on d0, 7, 14, 28, 56, 84, 91, and 112. Body condition scores were recorded monthly. Data were analyzed using PROC MIXED of SAS and weights were analyzed with repeated measures. Significance was determined at P < 0.05. During the initial week post-abrupt weaning, Abrupt calves lost weight, Fence maintained weight, and Late calves gained weight (-0.4, 0, and 0.7 kg/d, respectively; P < 0.05). Over the complete weaning period (d0 to 112), Abrupt and Late weaned differed (P < 0.05) in their gains, while Fence was not different (P >0.05) than either treatment (0.58, 0.64, and 0.62 kg/d, respectively). Cow overall ADG was not affected by weaning treatment (1.2, 0.8, and 0.5 kg/d, respectively; P > 0.05). From d28 to 84, lactating Late cows gained less weight than Abrupt and Fence (0.3, 0.8, 0.8 kg/d, respectively; P < 0.0001). This contributed to a -0.1 BCS decrease at d112 for Late compared to a 0.3 and 0.2 BCS gain for Abrupt and Fence, respectively (P < 0.0001). Cows weaning calves after 10 mo of lactation were lighter than cows weaned after 7 mo; however calves remaining with their dam maintained growth rates similar to grain supplemented weaned calves on pasture. While treatments influenced cow measures, all remained within normal values, therefore late weaning may be an option for producers to sell heavier calves without grain supplementation if marketing older calves.