Colostrum is the start that dairy calves need
Dairy Moosing: the critical importance of colostrum management and feeding for dairy calves.
(You can also learn about the importance of colostrum in this Dairy Moosings podcast.)
Colostrum is the first milk that the cow gives after calving, and it is high in Immunoglobulins (Ig), protein, energy and vitamins. Immunoglobulins are extremely important for the calf’s immunity. Igs are produced by the cow in response to pathogens that she has been exposed to, and thus provide a passive immunity to the calf to protect her until she can develop her own active immunity. Many people do not realize that, while human infants are born with an active immunity system, calves do not have an active immunity system because a cow’s placenta cannot pass Igs from cow to calf, unlike the human system.
This means calves are born without protection from diseases and it is up to us as calf raisers to make sure we provide them with that protection through colostrum feeding.
Current research recommendations are to feed one gallon of colostrum as soon after birth as possible, and another 2 quarts, 12 hours later. Research indicates that we need to get a sufficient amount of Igs into the calf within the first 24 hours because the ability of the calf to absorb these into the blood from the gut decreases very rapidly during that first 24 hours. In fact the ability to absorb the Igs from gut to blood, goes from 66% of the ingested Igs at 6 hours from birth to just 11% at 24 hours.
Quality is important too. If we feed colostrum that has fewer Igs per gallon, than that first feeding is not going to be as good as we might hope. Igs are also very specific to the pathogens that the cow may have come in contact with, so quality includes diversity in Igs present. Since older cows have had time to be exposed to more pathogens, they would naturally tend to have higher quality colostrum. However, with good vaccination programs on farms, colostrum from a cow that calved for the first time may be of sufficient quality as well.
The quality of colostrum may also be affected by the amount of colostrum produced at first milking, though this is may be related to a dilution affect, emphasizing the importance of early milking after calving. The only real way to determine quality is to test the colostrum.
One new technology is the use of a Brix Refractometer to measure the total solids in the colostrum, which are highly correlated to the Ig content. This new technology only takes a few drops of colostrum and temperature does not affect the test.
A Brix reading of 22 or greater indicates good colostrum for first feeding. Colostrum with a reading of 18-21 is considered Fair and should be reserved for 2nd and 3rd feedings. Less than 18 is considered poor quality.