John H. Kirk, DVM, MPVM
Veterinary Medicine Extension
University of California, Davis

Dairy calves are born without antibodies to protect them from diseases. At birth, the cow passes these antibodies to her calf via the colostrum. The colostrum contains the antibodies in the form of immunoglobulins (Ig) which provide the overall disease resistance of the calf. Colostrum, especially the first milking colostrum, contains large quantities of the protective antibodies or Igs. Adequate and timely consumption of colostrum by the calf is the key factor that controls early calfhood diseases and death loss. The amount of colostrum which has been absorbed can be measured by checking the Igs in the blood. A reasonable goal for Ig in the blood is 10 g/l. Your herd veterinarian can recommend an appropriate method or lab. Less than this amount is usually termed failure of passive transfer and results in increased levels of early calfhood disease and deaths (3x to 10x increase).

Timing of first feeding

Timing of first feeding of the colostrum is very critical. Two primary factors are involved: loss of absorptive sites and bacterial colonization of the intestine. As soon as the calf is born, the ability of the colostral Igs to cross from the intestine into the blood stream begins to decrease. By 24 hours after birth, colostral Ig absorption has ceased. At the same time that colostrum is being absorbed, bacteria are attempting to enter the blood stream. The colostrum must get into the blood before the bacteria in order to prevent disease. For maximal protective effect, colostrum should be fed at birth. As every hour passes after birth, absorption is decreased. A second feeding should be given within 12 hours after birth.

Amount of colostrum

The amount fed should depend on the size of the calf. Big calves need more than small ones. The minimum amount to feed at the first feeding is 2 liters of first milking colostrum for the smallest calves, however, normal or large size calves should get 4 liters. On a body weight basis, calves should get between 10% and 15% of their body weight at the first feeding. A second feeding of first milking colostrum of the same amount should be given within 12 hours after birth.

Quality of colostrum

The amount of Igs in the colostrum determines the quality. First milking colostrum usually is of higher quality than second milking. Second milking is better than third. After that it is not really colostrum in the sense of providing protective Igs for absorption. The quality can be estimated by using a colostrometer to measure the Ig level. Older cows usually have higher quality colostrum than heifers calving for the first time. Dry cow vaccinations improve the colostrum quality. Cows with large volumes of colostrum (>20 lbs) may have poor quality colostrum.

Method of feeding

You can not count on the calf to nurse adequate amounts of colostrum from the dam. Over 40% of the calves left with the dam will have failure of passive transfer and be left unprotected. Nipple bottles are a good method as they allow the dairyman to control the time of feeding and to know the quantity consumed. Esophageal feeders can be used to save time in calves which are slow to nurse a bottle.

Nutritional benefits

In addition to the Igs which colostrum provides, it is rich in vitamins and concentrated in nutrients which the calf can use to get off to a good start. If colostrum is frozen for later use, it should be thawed slowly. Overheating colostrum during thawing (>130 F) will destroy the Igs.

Environmental interactions

Colostrum is a wonderful source of Igs, vitamins and nutrients for the newborn calf. However, as great as colostrum is, it still can not overcome the effects of a calf being born in a dirty environment. Calves which are born in a manure-covered closeup pen or which nurse a filthy teat when they first stand up will be overpowered by bacteria inspite of colostral absorption. All equipment used to feed colostrum to newborn calves should be kept very clean.

Supplements

There are no supplements for colostrum which are more conveniently located or in ample, low cost supply than the colostrum which the dam produces for her calf. Rely on colostrum! Commercial supplements are less effective.