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Understanding Colostrum with Dr. Jeff Hill

Being ready and prepared before the start of calving is essential for a successful calving season. A key component for any calving tool kit should be a quality supply of colostrum.

Why is Colostrum Critical

Colostrum, or first milk produced by the mother after birth, is high in nutrients and antibodies. A newborn calf lacks disease protection because antibodies do not pass across the cow’s placenta to the fetus. Antibodies in colostrum provide calves with their initial protection. Penn State University highlights how antibodies from colostrum, or passive immunity from the cow, protect newborn calves until their immune system is functional.

Antibodies from colostrum protect calves until their immune system is functional

Antibodies from colostrum protect calves until their own immune systems are fully functional

Source: Penn State

Calves need about two quarts of colostrum (or at least five percent of the calf’s body weight) within four hours of birth – ideally within 30 minutes – and one gallon within 12 hours.

Time is important because a newborn calf’s digestive tract allows antibodies to pass directly into the blood. After 24 hours, the calf’s intestines cannot absorb antibodies intact. The absorbed antibodies protect against invasion of pathogens while antibodies that are not absorbed play an important role in protection against intestinal disease.

Colostrum also contains transferrin and lactoferrin, proteins that bind iron and act as an antibacterial in newborn calves, to protect them from disease. These factors, together with immunoglobulins, the antibodies in the colostrum from the cow, limit growth of bacteria in the gut. The graph below shows how a calf begins to lose its ability to absorb immunoglobulins from the cow after birth and why time is critical.

Effect of Time of Colostrum Feeding on Percent Immunoglobulin Absorption

Effect of Time of Colostrum Feeding on Percent Immunoglobulin Absorption

Source: Ag Web

How to Increase Colostrum

Allowing the calf to nurse from the cow is the most efficient method of feeding colostrum to maximize the immunity received. However, a weak calf can often take more time to get up and time is not on their side. Quick energy sources and bioactives can help get newborn calves up and drinking while adding immunological support.

Related: Start Strong for Calves, a bioactive oral drench, helps increase calf energy and colostrum intake.

What’s the Best Colostrum to Use?

Sometimes it’s not possible to get the calf up to nurse due to problems with the cow or calf. In these cases, the calf will need to be fed colostrum. Acquire colostrum by milking the cow as soon as possible after calving or use colostrum that you have previously acquired from a healthy cow. Acquired colostrum should be from cows in at least their third lactation rather than heifers. Good indicators of quality colostrum is a yellow color and a thick, creamy consistency.

Previously obtained colostrum must be kept frozen to protect the integrity of the large protein molecules that make up the various immunoglobulins, the antibodies from the cow. Fresh colostrum can be stored in one-quart doses in a gallon-size resealable bag. Lay the bags flat to freeze in the freezer. When the time comes to thaw the colostrum and feed it to the newborn calf, the “best practice” is to thaw in a warm water bath at 122 degrees Fahrenheit for one hour. Avoid thawing at room temperature or in a microwave oven.

Commercial colostrum replacers contain more than 100 grams of immunoglobulin per dose. Always read the label before purchasing. It’s important not to confuse supplements and replacers. Supplements are used to boost antibody protection a calf gets from nursing and contain 40 to 60 grams of immunoglobulins, which is not enough to provide protection in a calf that has not nursed.

How to Administer Colostrum

Colostrum or colostrum replacer will need to be administered by bottle suckling or tube feeding within a few hours of birth for maximal absorption of immunoglobulins. The general rule of thumb is the sooner colostrum is ingested the better.

If there is any question if a calf has received adequate colostrum, then colostrum should be administered immediately to the newborn. Calves that miss getting timely colostrum ingestion are much more likely to suffer from calf scours, which can have lifelong effects on general hardiness and disease resistance.

Overall, colostrum consumption is critical for calf success but also lifelong success of the cow. Ensuring each calf receives adequate colostrum levels should be number one on every farm.

To learn more about colostrum best practices, contact ruminant specialist Dr. Jeff Hill at 507-337-6916 or email

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