One of the great mysteries of calf raising is determining when calves can be weaned. This Calf Note will help you to identify when your calves are ready for weaning. It might help you to save a little money and grow healthier calves.
The criterion that must be satisfied before weaning is adequate rumen development. When you take liquid (milk, replacer, etc.) away from the calf, it must be able to obtain sufficient nutrients from the dry feed it consumes after weaning. Many of these nutrients are provided by ruminal fermentation, so the rumen must be “up and running” before the calf can be weaned. But, most calf raisers don’t measure “rumen development”. They typically rely on some other criterion for weaning – most frequently age of the calf.
When you wean according to the age of the calf, you assume that the calf will have adequate rumen development at the time of weaning. For example, if you wean your calves at eight weeks of age, you assume that the calf has sufficient rumen development by that age to be weaned. Most calves will have sufficient rumen development to be weaned by about 4 weeks of age. Unfortunately, if a calf develops scours and goes off feed, or if the starter is of poor quality or not available, or if water is not available, the calf may not be ready to wean by 4 weeks. And that’s when problems occur.
Calves typically require a couple of weeks before they begin eating measurable amounts of starter. Now, that doesn’t mean that you don’t have to feed starter to your calves for the first two weeks. You do. Calves need that time to figure out that calf starter is something to eat, that it tastes good (hopefully), and that they can satisfy their hunger by eating it. Thereafter, it takes at least a couple of weeks for them to eat enough starter to develop the rumen to the point where the calf can be weaned. If there is an interruption in starter intake during that time, rumen development may be delayed, and the calf may not be ready for weaning.
How much starter does a calf have to eat to be ready for weaning? Well, it depends somewhat on who you ask. My recommendation is this — when a Holstein calf is consuming 2 lb (1 kg) of calf starter per day for two consecutive days, then it will be ready for weaning. Other recommendations include 1.5 lb/day (700 g/day) for two days, and 3 lb/day (1.4 kg/day) for two days. Jerseys are a little different. They’re ready to be weaned at about 1 lb/day (450 g/day) — and this usually occurs about 5 weeks of age.
To be sure that your calves are ready to wean, you need to know how much starter they’re eating every day. You also need to give them the opportunity to consume an adequate amount of high quality, nutritious, and palatable calf starter. Water must be available free choice, too. It is not too difficult to measure starter intake if calves are housed individually. Use a container (e.g., a coffee can) that can hold 2 lb (1 kg) of starter. Weigh out 2 lb (1 kg) of starter and mark the can (some people will cut the can so that it will hold the exact amount). From four days of age, begin feeding a small amount (a handful) until the calf begins to consume the starter. Increase the amount you offer every day until the calf reaches the mark on the container. When that amount is consumed for two days, wean the calf abruptly. Be sure to remove old starter from these preweaned calves daily. Note that the density of calf starter may change from time to time, so it’s important to reweigh your container regularly.