Get Your Calves Colostrum Within The First 6 Hours

In the last year, many producers have spent a great deal of time, effort and money selecting the right bulls, culling the less-productive cows, rotating pastures, putting up hay, balancing diets, vaccinating the herd and performing the other practices we place under the heading of “good management.” While these basic practices are very important for the success of the cowherd, there is one crucial process often taken for granted: colostrum management.

Colostrum, the cow’s first milk, is not only important for the health of the neonate (newborn calf), but has a profound effect on the future performance of the calf all the way through the feeding period.

About 5-6 weeks before calving, immunoglobulins from the cow’s serum are concentrated into the colostrum. These immunoglobulins are such large molecules that they can’t pass through the placenta directly to th
e fetus. So, in order to convey some level of immunity to the neonate, colostrum must consumed.
However, it must be high-quality colostrum and the calf must ingest it at the right time. This is because the immunoglobulins in colostrum are absorbed very efficiently in the small intestine of the newborn calf. At this early stage in life, the cells lining the intestine are able to absorb these large molecules. But it doesn’t take long for the intestine to “close,” at which point the immunoglobulins are no longer absorbed.

When to give colostrum

The rule of thumb I learned as I grew up was that colostrum must be fed in the first 24 hours of life. We need to forget that rule. At 24 hours, it’s estimated that only 10% of the immunoglobulins are absorbed. The new rule of thumb should be six hours or less. At this point, the intestine is still very efficient in absorbing immunoglobulins.

Once a calf is fed, the intestine starts to close fairly rapidly, which is fine as long as the first feeding is colostrum. If the first feeding is milk or milk replacer, followed by colostrum, the colostrum will be poorly absorbed even if it is given within six hours. So, it’s vitally important to make sure that the first feeding is colostrum and not milk.

This isn’t to suggest, however, that if the calf isn’t fed colostrum within six hours that it shouldn’t be fed any colostrum. Even if the immunoglobulins aren’t absorbed into the bloodstream, they do provide important protection from disease within the intestine. The importance of this defense should not be discounted.

How much colostrum should be fed? I’m not sure anyone can come up with an objective answer to this question. Some of it depends on colostrum quality – the lower the concentration of immunoglobulins, the more colostrum that needs to be fed.

First-calf heifers, for instance, will typically have lower-quality colostrum than mature cows. Cows and heifers that leak colostrum just prior to or during parturition will also have lower-quality colostrum.

Generally, two quarts of colostrum should be the minimum amount fed. In my opinion, it would be an ideal situation if each calf got two quarts of good-quality colostrum by two hours of age, followed by two more quarts of colostrum by six hours of age.

Colostrum shouldn’t be taken for granted. It’s provided free of charge for every calf that hits the ground, and good herdsmen should take full advantage of this free gift of improved production. Make sure your calves get adequate colostrum in a timely manner. If you would like to learn more about colostrum management, see your herd health veterinarian for advice.