Age at Weaning and the Cost of Raising the Milk Fed Dairy Calf

Posted: December 26, 2006

The age at which you decide to wean a dairy calf will have a definite impact on the cost of raising that calf.

Often the actual total cost for raising a calf will not completely determine the growth and resulting age and weight at calving. That is because there are so very many ways to raise a calf and a large range of costs to accomplish this task. Weaning age can have a large impact on calf raising costs. Dairy calves are ready to be weaned when they eat 1.5 to 2 lbs of calf starter for 3 consecutive days. Often calves are weaned weeks after this occurs. Why? Well, often it is because of tradition. Calves have always been weaned at 8, 10, 12 weeks—or even later. Average weaning age in the US is moving to less than 60 days, but the change is slow for many farms because of long-standing tradition.

Extensive studies at Penn State University and The University of Wisconsin have shown that often the pre-weaned dairy calf requires more minutes of time per day to feed and care for than any other animal on the farm on an ongoing basis. In addition, these studies showed that the pre-weaned calf is the most expensive replacement animal to feed and care for in terms of dollars per day. Of note is that the cheapest replacement animal is the first group after weaning. The interesting point to realize here is that your management and attention to weaning age (time) determine when the change is made from most to least expensive.

Weaning age has been a topic of recent research at Penn State. We studied the impact of weaning calves at 3, 4, 5, or 6 weeks of age. Calves were monitored until 8 weeks of age for health and growth impacts through the post weaning period. Calves were fed a 23 percent protein, 15 percent fat milk replacer at 10 percent of birth body weight, or about 1.2 lbs of replacer per day (10 oz/feeding). In addition, calves were fed a high quality, free-choice calf starter (20 percent CP) with attention to assisting calves to eat if they were not beginning to consume starter by 5 days of age.

What we found was that calves weaned at 4, 5, or 6 weeks of age were exactly the same through 8 weeks of age in terms of health, growth (weight and height), and feed efficiency. The primary difference between groups was in the rearing cost. Calves weaned earlier had lower rearing costs due to reduced labor and slightly lower feed costs. Calves weaned at 3 weeks, as would be expected, were lagging behind in growth and required more attention to get them eating 1 lb of grain per day by weaning time. They were less efficient at converting feed to gain and had slightly more health concerns than the other calves. In short, weaning at 3 weeks was likely too young in this study, although USDA data shows us that there are a small number of farms in the US that wean calves at this age for all or part of the year.

Now for the feed cost issues of 2006-07. Milk replacer ingredients have seen sharp increases in price over the past months due to direct competition for ingredients that are used in both calf milk replacer and in the human food industry. Many convenience foods use whey proteins to improve food quality and flavor. This competition is real and is likely to remain an issue for the long term. This means that feeding whey-based milk replacer to calves may not be as economical as it used to be. It also means that if we can wean calves earlier, we can reduce the amount of milk replacer fed and be able to control the costs of raising calves even if the price remains high. Studies showing no difference in growth rates and no impact on future performance should help defend your decision to wean earlier. Calves do well on calf starter, are often healthier due to less scours, and they normally require less individual attention. Early weaned calves can therefore require less feed costs and less farm labor.

The steps needed to reduce your age at weaning are to offer free–choice, high quality calf starter at 1 or 2 days of age, be sure calves are eating some by 5 to 7 days of age—and if not, show them what calf grain is by either hand feeding some or putting some in the bottom of the milk bucket after milk feeding. Finally, know how much grain it takes to make 1.5 to 2 pounds a day so that you can note when calves are eating that amount for 3 to 5 days and are ready to be weaned. A spring-load feed scale is a handy tool in the calf area. Don't forget the water- calves will eat much more starter if offered free choice water. As always, careful attention to calf health is critical and will have a great impact of the success of your calf system.


Jud Heinrichs
Dairy and Animal Science Extension