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Colostrum – The Why, When, and How to Feed

By Grace Thomas, M.Agr.Sc. P.A.S.

Feeding colostrum is the single most important management factor in successful calf rearing. The antibodies present in the colostrum are transferred across the small intestine of the calf, this passive transfer provides short term protection to the calf. This gives the calf time to build its immune system and antibodies. Colostrum is the gatekeeper for growth and future production, not only is it a vital source of immunoglobulins, it contains a high level of energy, growth promoters, hormones, and vitamins.

Measuring the serum immunoglobulin G (IgG) level in the calf 24-48 hours after birth will help determine the success of the passive transfer of immunity in the calf.

A serum level of IgG>10g/L is considered as a successful passive transfer, anything lower is called the failure of passive transfer (FPT). Failure of passive transfer rates on US dairy farms has improved in the last decade; the latest study from the USDA National Animal Monitoring System 2015 confirms 14% out the 1700 calves studied had FPT.

Calves perform better when their immune system is not compromised. Calves with FPT not only have increased morbidity and mortality rates (Figure 1), the impact of the disease leads to long term losses such as lower growth rates, feed efficiency and increased age at first calving.

Figure 1: Survival rates of calves with adequate and inadequate immunoglobulin concentrations in blood serum Source: USDA National Animal Health Monitoring System, 1992

Figure 1: Survival rates of calves with adequate and inadequate immunoglobulin concentrations in blood serum Source: USDA National Animal Health Monitoring System, 1992

The four management factors that can help increase passive transfer rates on the farm are

• Quality
• Quantity
• Quickness
• Cleanliness

Goal: Colostrum IgG level >50g/L

Not all colostrum is equal, quality can be evaluated by measuring the IgG concentration, a concentration >50g/L is considered high quality. Many factors affect the quality and not all can be controlled for example age, breed and parity.

On-farm factors that can be controlled, are listed below:

Factors table

Goal: Feed 10% of body weight

To achieve high successful passive transfer rates, feed colostrum at 10% of body weight (3-4L) for first feeding or within 6 hours of birth. This will help reach the goal of the calf consuming 150-200g IgG.

Goal: Feed within 1-2 hours

The calf is born with an open gut that will non-specifically absorb large protein molecules such as antibodies. The ability of the intestine to absorb antibodies diminishes over the first 24 hours after birth (Figure 2). The ideal time

Figure 2. Effect of time of colostrum feeding on percent immunoglobulin absorption. Source: Waterman, 1998

Figure 2. Effect of time of colostrum feeding on percent immunoglobulin absorption. Source: Waterman, 1998

for the calf’s first feeding is 1 to 2 hours after birth; this is when the efficiency of absorption is at its highest.

Ensuring the calf receives enough colostrum is more important than the method used to administer it. Dairies that leave calves to suckle/nurse routinely have the highest failure rates. This could be due to calves being slow to get up and nurse. Also once the calf is up there is no way to know how much the calf has consumed. Also, suckling leaves the calf exposed to the pathogens in both the environment and on the dam/teat. Research has shown (Chigerwe et.al, 2012) that calves fed via an oesophageal tube or nipple bottle had similar passive transfer rates, ensuring the calves received enough volume quickly enough was the most important factor.

Goal: Total plate count <100,000 cfu/ml, Total coliform count <10,000 cfu/ml

The two main concerns when feeding contaminated colostrum are bacterial pathogens and bacterial interference. High levels of bacteria in colostrum interfere with immunoglobulin absorption.

Colostrum from known diseased cows (Johnes, Mycoplasma) should not be fed to heifer calves. If the disease status of a cow is not known, do not pool the raw colostrum; follow the “one cow to one calf” rule. This helps in preventing the spread of a disease through a herd.

If possible feed colostrum within 1-2 hours following milking, after this the colostrum needs to be refrigerated. It can be stored in a refrigerator for up to 2 days. After 2 days bacteria counts rise above acceptable levels. Adding preservatives or heat treating can help increase the refrigerated shelf life of colostrum. Colostrum can be frozen for up to a year, but care must be taken in thawing. Microwaves must not be used as they can damage the immunoglobulins; the best method is to thaw slowly in a warm bath of water.

Any equipment used to harvest, store or feed the calf needs to be evaluated as a possible source for bacterial contamination of colostrum. If there is consistently dirty colostrum on-farm, this is a good area to identify if there are any deficiencies in the cleaning of equipment.
Talk to your Agri-King representative today about your dry and pre-fresh programme. Healthy dry cows that calf without metabolic problems will produce healthy calves and quality colostrum.


Chigerwe, M., Coons, D.M. 2012. Comparison of colostrum feeding by nipple bottle versus oroesophageal tubing in Holstein dairy bull calves. J. Am. Vet. Med. Assoc. 241:104–109.
National Animal Health Monitoring System. 1992. Dairy herd management practices focusing on preweaned heifers. USDA, Animal and Plant Health Inspection Service, Veterinary Services, Fort Collins, CO.
Quigley JD, Lago A, Chapman C, Erickson P & Polo J 2013. Evaluation of the Brix refractometer to estimate immunoglobulin G concentration in bovine colostrum. Journal of Dairy Science 69: 1148-1155.
Waterman, D. (1998) Colostrum. The beginning of a successful calf raising program. Madison / New York: Ph.D. Milk specialities. Dairy Quality University