Strategies for Successful Weaning of Dairy Calves

Posted: November 3, 2005

With weaning, it is essential that adequate rumen development has occured. Without a fully functional rumen, calves will be unable to utilize nutrients provided in the post-weaning dry feed diet. The result is a growth slump for one to three weeks after weaning.

Many producers regularly and successfully wean calves at four to six weeks of age. Weaning at this age is cost effective because it gets calves started on dry feeds sooner, saving money on labor and feed costs. While weaning calves early makes good sense economically, it is essential that adequate rumen development occurs before weaning. Without a fully functional rumen, calves will be unable to utilize nutrients provided in the post-weaning dry feed diet. The result is a growth slump for one to three weeks after weaning. Keep in mind, this growth slump after weaning can occur at any age if the rumen is not well developed. Consumption of calf starter and water lead to the production of volatile fatty acids in the rumen, which in turn stimulates rumen development. This takes about 3 weeks to occur, so early weaning requires that grain and water be consumed within the first week of life.

With proper care and management, the vast majority of calves on most farms can be weaned by five weeks of age; however, weaning decisions should not be based on the calendar alone. The recommended weaning criterion is the amount of starter eaten by the calf. This method allows individual adjustments to weaning that keep unhealthy calves on milk and allow healthy calves to switch to dry feed. If five-week weaning fails, look for and remove other limiting factors, such as not feeding adequate colostrum, poor ventilation, not feeding high quality calf starter, wet, damp housing, or other stresses placed on calves. At weaning, calves face significant stress due to changes in their diets, housing, and environments. As a result, calves may lose weight, eat less, and become more susceptible to infection. The key to limiting this post-weaning slump is to minimize stress.

A major source of post-weaning stress can be the change in diet and new dependency on dry feeds. If calves are weaned before adequate rumen development has occurred, this stress will be much greater. Offer high quality starter and clean water beginning a few days after birth to ensure adequate rumen development. Also, do not wean calves less than four weeks of age, and be sure calves eat two pounds of grain for three consecutive days before weaning. This ensures continued adequate energy intake after weaning. Obviously, to know if the calf is eating two pounds, you must know how much starter is fed each day. Weigh out two pounds of starter and mark the amount on the container used to feed calves to ensure accuracy in the amount fed each day. Although milk may be removed abruptly, it is recommended that changes in dry feed be made gradually. Feed the same starter for at least a week after weaning and then mix starter with the weaned-calf grain mix to allow calves to adjust gradually to their grower diet.

Give calves time to adjust to weaning before adding the stress of moving and adapting to group housing. Wait a week after weaning before you move calves to new housing, and limit groups of newly weaned calves to four to six animals to ease the transition. This allows calves to adapt to the social aspects of group housing. Small groups ease the stress of competition for shared feeding and resting areas. The first group postweaning clearly appears to be the most important for social adaptation. Beyond this first small group, subsequent groups can be much larger and quite different in terms of feeding systems and management with little, if any, detrimental effects on the growth and development of the heifer.

Since calves commonly encounter a wider variety of pathogens when moved to group housing, only healthy calves should be weaned. Not only will weaned calves be exposed to more pathogens; their immune systems also might be suppressed by the stress of changing diets. Housing areas must have adequate ventilation to reduce the risk of respiratory infections. In addition, the area should be clean and well bedded to limit exposure to fecal pathogens. Continue to feed a coccidiostat in the ration to reduce the risk of coccidiosis; weaned calves are especially susceptible to this disease because the stress of weaning can depress the immune system.

Avoid dehorning or vaccinating calves around the time of weaning as well. These are additional stresses to the calves’ systems, and they are relatively easy to plan around. Finally, weaning during weather extremes might worsen stress. Weather can stress calves by changing energy requirements and suppressing the immune system. A severe change in the housing temperature is an added stress on the newly weaned calf. Adding the stress of weaning may be too much and might encourage infection and/or weight loss.

Coleen Jones, Research Associate and Jud Heinrichs, Dairy & Animal Science Extension