The first time a calf suckles after birth could be labelled as the most important meal that the calf ever consumes.
Adequate colostrum intake is essential to getting a calf off to a good start.
Newborn calves are born with virtually no immunity of their own. The cow’s placenta does not allow antibodies to pass from the mother to the calf during pregnancy. This means that the calf must receive its initial immunity from the antibody rich colostrum, which is the first milk of the cow.
This initial immunity is essential because it provides protective antibodies against many of the diseases that affect newborn calves, such as calf scours, navel abscesses, arthritis and pneumonia.
Even the vaccines we use to prevent scours in calves rely on this passive transfer of immunity in the colostrum.
Colostrum’s components are probably more similar to blood than milk. It contains important antibodies against infectious diseases but is also rich in fat, energy, vitamins A and D, blood cells and growth factors.
The calf is able to absorb these antibodies (also known as immunoglobulins) at a significant level only during the first 12 hours of life.
However, the gut begins to lose the ability to absorb these antibodies by six hours after birth.
The gut’s closure to antibody absorption is a gradual process, but it begins to decline rapidly until complete closure occurs at approximately 24 hours.
The antibodies can still have some local effect after the gut closes, but they can no longer be absorbed into the bloodstream.
In most cases, calves should be up and nursing within two hours of birth. Calves that don’t nurse within two hours should be identified and either helped to nurse on the dam or fed colostrum with a bottle or tube.
Calves should receive at least two litres of colostrum within the first six hours of life and another two litres by 12 hours of life. The volume of colostrum needed depends on the concentrations of antibodies in the cow’s first milk.
Colostrum from cows that produce a lot of milk will tend to have a lower concentration of antibodies because of a dilution effect. Heifers with less milk production will often have more concentrated colostrum.
We obviously want calves to get up and suckle on their own and avoid intervening where possible. However, this first meal of colostrum is so vital that we need to identify calves early that are unlikely to suckle on their own and intervene before six hours of life.
Calves that have calving difficulties, those that are abandoned or mismothered and those that are hypothermic in cold weather are at the highest risk of failing to receive adequate colostral immunity.
Pendulous udders and large teats can also make suckling difficult for even vigorous newborn calves.
The preferred intervention option is to milk the dam and use its own colostrum to feed its calf.
However, we must rely on other sources of colostrum if the cow or heifer does not have an adequate volume of colostrum or can’t be milked.
Using colostrum collected from another cow in the herd is also an option.
Collect colostrum from cows that lose their calves or that have an abundance of colostrum and need to be milked. It can be kept in the refrigerator for seven to 10 days to be used for other newborns.
Extra colostrum can also be kept frozen for up to a year. It should be gradually thawed in a warm water bath instead of heated to a high temperature because high heat can destroy the antibodies.
Another option is to use a freeze dried colostrum substitute. Read the label on these products because they do not all have adequate immunoglobulin levels. Your veterinarian can recommend a product that will have high enough levels of antibodies to act as a colostrum substitute.
Veterinarians no longer recommend feeding dairy cow colostrum to beef calves because colostrum from another farm can introduce diseases to your herd such as Johne’s disease or salmonella, which can have serious long-term consequences.
These diseases tend to be prevalent in dairy herds, and in some cases the colostrum quality may not be as high.
Several studies have shown that up to 25 percent of calves in cow-calf herds can have less than optimal levels of colostral immunity. Preventing calving difficulties, chilled calves and mismothering are important ways to ensure that calves are vigorous and more likely to suckle early and receive this essential protective immunity.
John Campbell is head of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.