Colostrum is very important for the newborn calf. A newborn’s immune system isn’t well developed when born and thus, it must rely on colostrum contained in the milk of its mother until it develops its own fully capable immune system when it reaches 1 to2 months of age. Colostrum is rich in antibodies and all sorts of immunoglobulins that are required to provide the calf with all necessary protection it needs from diseases.

Majority of the farms do a very good job getting colostrum into their calves. However, the lack of adequate colostrum or the failure to perform a passive transfer can be a challenge for people raising dairy bull calves. As mentioned earlier, calves are born without a fully functional immune system. So the colostrum is very important for them in order to keep them from diseases until their immune system fully develops. The immunoglobulins and antibodies content of colostrum can only pass through the intestinal lining of the calf within the first 24 hours from birth. As soon as 24 hour crosses, the intestinal linings may not be able to absorb as much immunoglobulins from the colostrum as it could within 24 hours from birth.

By 24 hours, the gut begins to close and it becomes difficult for the calf to absorb the antibodies in the colostrum. The intestine of the calf becomes impermeable to large proteins. When given opportunity to feed within 6 hours from birth, calves’ intestines can absorb 66% of the immunoglobulins in colostrum. But if they feed after 36-40 hours, they can absorb only about 6% of immunoglobulins. Colostrum contains 22% solid compared to 12% solid in normal cow milk.

Besides the 24 hour window, there is another very important thing that affects the passive transfer of immunoglobulins to the calves which is the quality of colostrum. Good colostrum contains about 55 grams of Igs per liter. If the quality of colostrum is less, the calves would be required to fed more colostrum in order to supplement their Igs needs.

How much colostrum does a calf need?

A calf should receive 5-6% of its body weight in the form of colostrum and that too within the first six hours of its life. It should then another round of colostrum in the same amount(5 to 6% of its body weight) when it is around 12 hours old. The volume of colostrum is about 8lbs per gallon. This means that a calf with the weight of around 80lbs will require around 4 lbs of colostrum in a single feeding.
For best results, it is necessary to give proper colostrum obtained and stored at your own facility. Commercial colostrum supplements are not that efficient and hence, the calves may not receive the same amount of protein. However, if there is a dearth of colostrum, you may rely on these more or less. These colostrum supplements are mainly obtained from processed bovine serums and can be absorbed more efficiently by the intestines.
Proper quality of colostrum administered within the first six hours of birth will produce best results and help the calf obtain the immune boosting factors including immunoglobulins and antibodies that it requires until its own immune system matures.