By T.L. Meyer and Karla Wilke
When grass is limited and/or cow body condition needs to improve, early weaning may be a viable option for cow-calf producers. Weaning removes any grazing pressure from the calf and removes milk production from the cow’s nutritional requirements, reducing her dry matter intake by 20%.
How early can calves be weaned? While calves have been shown to be weaned successfully as early as 45 days, keep in mind the rumen development of young calves will influence the weaning process. Around 85-90 days of age the calf’s rumen is developed enough to be considered a ruminant rather than a pre-ruminant. For this reason, waiting until 100 days of age to wean may provide an easier transition to the weaning diet. At this age, a calf consumes 1.5 to 2.0% of their body weight on a dry matter basis. Once milk consumption is removed, the calf will eat 2.3-2.5% of their BW on a dry matter basis. The diet fed must be highly digestible to promote high passage rate and feed intake to accommodate an early-weaned calf’s small rumen.
Early weaned calves require increased labor, particularly for daily feeding and close monitoring of intake and health to prevent problems early.
Preparing calves for early weaning may include introducing them to new feeds, feed bunks and/or different watering systems while still with the cow. Fermented feeds such as silage can be unpalatable if unfamiliar prior to weaning. Will the weaning facility allow lighter-weight calves to access feed and water easily? Early weaned calves should have at least 12 inches of bunk space. Work with your veterinarian to determine what pre-conditioning or preparation should be completed prior to weaning as well as developing a plan to manage any outbreaks of illness following weaning.
Separating cows from calves should be done with as little stress as possible. If facilities can manage it, consider variations of fenceline weaning or two-step weaning compared to abrupt weaning.
Source : unl.edu