By Justin Waggoner, Ph.D., Beef Systems Specialist, Garden City
Many cattle producers are weathering an exceptionally dry grazing season and may be considering early weaning calves. Many discussions about early weaning focus on managing lightweight calves with the benefits to the cow and the ranch becoming lost in the discussion. Weaning calves 30-60 days earlier than normal (approximately 120-150 days of age) is an excellent management tool that reduces the nutrient requirements of the cow and reduces daily demand for forage resources. A 450 lb spring-born calf is capable of consuming approximately 7 lbs of forage per day. A dry 1400 lb cow can easily consume 28 lbs of dry forage per day (2% bodyweight). If we divide the 28 lbs of forage needed to maintain the cow by the 7 lbs spared in a pasture by removing the calf, we learn that for every 4 days that a calf is not grazing with the cow we get one grazing day for the cow. If we wean calves approximately 30-60 days early, we gain an additional 1-2 weeks of forage to support the cow. Additionally, research at Kansas State University (Bolte et al, 2007) documented that weaning calves at 100 to 145 days of age increased body condition scores of cows grazing native pastures from an average of 5.46 to 5.85 in 120 days. The change in cow body condition score ranged from 0.25 to 0.50 of a condition score on this study. These results are more impressive if we also consider that forage quality was likely declining and yet these cows were still able to increase body condition. The results of this study demonstrate that the optimum time to improve body condition on cows is immediately following weaning as the nutrient requirements of pregnant cows are lowest during this time. Furthermore, what is the value of improving cow condition in the fall to the ranch in a tough year? A lot, especially when the benefits may include less feed/supplement during the winter and improved breed up in the subsequent production year.
For more information, contact Justin Waggoner at jwaggon@ksu.edu.
