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Colostrum: Not just for the first 24 hours

Jim Quigley Published on 11 November 2010

During a recent visit to a 600-cow dairy in Wisconsin, I visited with Joe, the manager. He was looking for ways to improve his calf rearing and asked about feeding colostrum.

“I’ve always heard that colostrum was important in the first 24 hours. But after that, colostrum proteins don’t get into the calf’s blood,” Joe said. “Now I’m told that colostrum is good even after the first day. What’s the right answer?”



Well, the right answer is … both. That’s right – colostrum is essential in the first 24 hours of life, but it is also valuable for the next several days. Here’s a quick explanation as to why.

Colostrum contains antibodies (also called immunoglobulins, or Ig) that protect the newborn calf against disease. The job of antibodies is to identify and bind to specific pathogens such as salmonella or rotavirus. After binding, they signal the calf’s immune system to kill the invading pathogen.

Calves (and many other animals) are born without antibodies, so they’re very susceptible to disease because they can’t identify invading pathogens. Feeding enough high-quality colostrum to provide 150-200 grams of IgG (one form of Ig) is essential. During the first 24 hours, the calf can absorb intact antibodies into the bloodstream. Normally, proteins are digested in the intestine into amino acids prior to absorption. However, because the structure of an antibody is so important to its function, the calf is born with a special ability to absorb proteins intact for a limited time. This gives the calf time to drink colostrum and absorb antibodies into its bloodstream without destroying their structure.

When colostrum doesn’t have enough antibodies (common on most dairies) or it is contaminated with bacteria (even more common), the colostrum isn’t suitable for the calf and should be replaced with a commercial colostrum replacer.

What’s the value of colostrum and why should we continue to feed it after 24 hours? To understand this, we need to know a little about diarrhea-causing pathogens. Most of these bugs are swallowed by the calf – from dirty bottles, nipples, buckets, other calves, unclean hutches or the dirty hands of a calf worker. Once swallowed, bacteria and viruses travel to the intestine where they attach to the intestinal wall and begin to reproduce. They typically destroy intestinal cells, causing metabolic upset, leakage of cell contents into the intestinal lumen, maldigestion, osmotic upset and, ultimately, diarrhea.


Antibodies are effective when they attach to the pathogen. Because most pathogens are found in the intestine, antibodies must move from the blood back into the intestine to bind. The calf has an elaborate system to recycle antibodies from the blood back into the intestine on a continual basis. Researchers at Washington State University estimated that 3-5 grams of IgG moved from the blood into the intestine every day in colostrum-fed calves.

Once in the intestine, antibodies bind to any pathogen they find. If they don’t find a pathogen, they may be digested and used as protein, or they may be excreted into the feces. Several researchers have found immunologically active IgG in feces from several species of animals, indicating that the IgG are providing intestinal protection. So these antibodies aren’t absorbed but provide a level of local immunity for the young calf.

“That’s great, Doc,” Joe said. “But I don’t have a lot of extra colostrum. How should I divvy it up?”

My suggestion was simple. “Feed enough colostrum on the first day. That’s most important.” I continued, “If you have clean colostrum that tests yellow or red on the colostrometer or any extra good colostrum, feed that after 24 hours.”

Joe then asked, “I don’t get much of that, Doc. Are there other sources of antibodies I can feed?”

“Absolutely,” I replied. “Feeding a consistent supply of functional proteins prior to weaning is an easy and cost-effective way to improve the health of your calves and reduce the risk of diarrhea.”


“Wait, Doc,” Joe said. “You were talking about antibodies and now you’re talking about functional proteins. What’s the difference?”

“Functional proteins,” I explained to Joe, “are a category of proteins that, like antibodies, do something once they’re consumed by the animal. Antibodies are one example of a functional protein. In fact, colostrum contains many functional proteins besides antibodies. Other functional proteins in colostrum include lactoferrin, lactoperoxidase and others. They all work together to support and protect the calf.”

I explained to Joe that there are several sources of functional proteins that help support calf health and growth. The three most common sources include colostrum, spray-dried egg and spray-dried animal plasma and serum.

Spray-dried egg provides specific antibodies if the birds were hyperimmunized. Eggs also contain other functional proteins such as lysozyme. Spray-dried eggs may have value in specific pathogen situations, but specificity is critical and sometimes they provide no benefit if your problem doesn’t match the specific antibodies in the product.

Spray-dried plasma and serum products are widely used in the swine industry for newly-weaned piglets to reduce risk of diarrhea, improve growth and survival. New technologies have allow plasma proteins to be used in calf milk replacers and in stress-type feed additives. The combination of serum antibodies plus other functional proteins (α-2 macroglobulin, transforming growth factor β) make plasma and serum a powerful tool in protecting calves against diarrhea-causing pathogens. Producers report excellent results using functional plasma proteins instead of feed-grade antibiotics for their calves. Plasma in milk replacers is growing as producers see greater health and growth due to the presence of highly-functional proteins.

Joe has several tools available to help his calves stay healthy during the first few weeks of life. His excess and low-quality colostrum is a great start for a few days. To supplement that, he’ll use a milk replacer containing plasma plus a serum containing stress pack when his calves typically break with diarrhea, around seven to 10 days. Since he doesn’t typically culture specific pathogens, using spray-dried egg probably doesn’t make sense.  PD

Jim Quigley
  • Jim Quigley
  • Vice President & Director of Calf Operations
  • APC Inc.