The cow’s first milk is vital to the newborn calf’s survival. Calves that obtain adequate colostrum soon after birth stay healthier than calves that are slow to suckle or don’t get enough.
“I have been working with many critical-care newborns and this is why I am interested in colostrum,” says Dr. Lisa Gamsjaeger.
Gamsjaeger is a large animal veterinarian and currently a PhD student with Dr. Claire Windeyer at the University of Calgary’s faculty of veterinary medicine. Windeyer has been researching topics around newborn calves for several years.
Gamsjaeger says that it can be difficult to fight diseases that could have been prevented with enough high-quality colostrum as soon as possible.
“This is because the calf is born without any antibodies,” she says.
The maternal antibodies from colostrum provide the calf with passive, or temporary, immunity against many of the infections it may soon encounter.
“Colostrum also contains helpful cells and antimicrobial peptides, which are defense mechanisms that help protect the calf. In Canada, many producers calve in winter so the two main components that are crucial are the antibodies and the fat. The high level of fat in colostrum fuels the brown fat in the calf immediately, which provides instant energy and enables him to keep warm, and prevent hypothermia and frostbite. Colostrum at cow body temperature provides some warmth as well,” she explains.
The calf also needs to pass meconium — the dark-coloured sticky material that was in his intestines at birth. Ingesting colostrum stimulates gut motility and helps it pass the meconium, Gamsjaeger says. Once the colostrum is coming through the gastrointestinal tract, feces change from brown to yellow.
In cold weather, if a calf doesn’t nurse quickly, it chills quickly. If its mouth gets cold, it can’t suckle.
“The calf’s ability to absorb antibodies may also be decreased; there is less blood flowing to the gut,” Gamsjaeger says.
When cold, the calf’s energy is directed towards vital organs such as heart, lungs and kidneys. That leaves less oxygen-rich blood servicing the gut to help absorb all the important ingredients in the colostrum, says Gamsjaeger.
Getting high-quality colostrum
Even though producers know that calves need to have colostrum soon after birth, there are still high numbers of calves that don’t get enough.
“Immunoglobulin levels of 24 grams per litre or higher is adequate. Levels below that have been associated with increased risk of disease and death. About one-third of all calves don’t achieve adequate transfer of passive immunity in Western Canada.”
Hard winters or inadequate nutrition for the cow may hinder production of high-quality colostrum, leaving it lower in nutrients and antibodies.
Sometimes the producer doesn’t find the newborn calf quickly enough, and doesn’t know whether it suckled, or suckled soon enough. Gamsjaeger says the calf should have the first feeding within two hours of birth to transfer enough of the antibodies and nutrients, and stay warm. This is the optimum time for absorbing antibodies directly through the gut wall and into the blood and lymph systems. After about six hours the calf has lost half of the capacity to absorb antibodies.
“Every calf is different. Some lose that ability sooner. It depends on whether it was an easy birth or how much stress the calf has suffered. In the average calf, ability to absorb any antibodies from the gut is completely gone after about 24 hours,” says Gamsjaeger.
Colostrum still has benefits after that period. The calf can use some of the other ingredients for a longer period, including some of the defense mechanisms that fight bacteria locally within the gut.
In a natural situation, the calf nurses the dam frequently and is getting what is left of the colostrum she produced as it is gradually replaced by incoming milk. The passive immunity gained by the calf from the dam may last a few weeks or a few months, depending on the quality and quantity of colostrum ingested, management factors and stresses suffered by the calf.
Colostrum from the cow’s own dam, or another cow on the same operation, is best. The herd’s cows pass on antibodies.
“We spend money to vaccinate cows (such as pre-calving scours vaccines) and we want those antibodies to get into their calves. The antibodies in that colostrum will also be specific to diseases on your own farm — what the cows have been exposed to every day in that environment,” she says.
Twins and calves that had to be pulled are most at risk for not getting enough colostrum. Dr. Jennifer Pearson, who is also working with Windeyer, found that 25 per cent of calves that had difficult births didn’t get enough antibodies.
Calves from heifers also might not get enough colostrum, either because they don’t have the quantity and quality as mature cows, or because they’re slower to mother their calves. Sick cows may also have poor-quality colostrum, she adds.
If a calf is unable to nurse and a producer can’t obtain colostrum from the cow, there are commercially available alternatives. Gamsjaeger doesn’t recommend buying colostrum from dairies. Beef cow colostrum averages 150 grams of immunoglobulin per litre, compared to 50 grams of immunoglobulin in dairy colostrum.
“Beef calves are often smaller than dairy calves and their stomach is smaller. They can’t handle three or four litres of colostrum in one feeding like we sometimes give dairy calves. Dairy colostrum won’t give adequate protection to the newborn beef calf. It’s almost impossible to give a large enough amount to a beef calf to achieve adequate immunity.”
Dairy colostrum also presents a biosecurity risk, especially if it isn’t pasteurized.
“You may have increased risk for transmitting Johne’s disease, BVD, salmonella and other diseases that may be present in the dairy herd,” says Gamsjaeger.
The best option is to use colostrum from a beef cow in your own herd. Gamsjaeger says it will keep in the refrigerator for 24 hours, and a year in the freezer.
Some commercial colostrum replacements are good, says Gamsjaeger, while others are inadequate. She recommends checking the label. Look for a product with 18 per cent fat or higher and a good immunoglobulin concentration.
“The higher the better, because then you can give less volume and the calf will still feel a little hungry.”
The colostrum replacement will provide necessary antibodies and some energy to stimulate the calf to seek more food. The calf should get up to nurse the dam after consuming the colostrum. But if the calf consumes two to 2.5 litres, it might not feel like suckling again soon, Gamsjaeger says.
Some products available in Canada contain 100 grams or more of immunoglobulin per bag. A producer might choose a different product depending on whether the goal is to completely replace or supplement the dam’s colostrum. For a complete replacement, Gamsjaeger calculated that a 100-pound calf would need 400 grams total to receive adequate immunoglobulin transfer.
Assessing colostrum quality
A person can get a rough idea about colostrum by its weight, colour and thickness. The more fat and protein it contains, the thicker and more yellow it may be.
Tests can provide an accurate assessment. Gamsjaeger and her colleagues have preliminary results from a project measuring colostrum quality on-farm.
“On-farm, we can use the Brix refractometer, used commonly to test dairy colostrum. For beef cattle, however, the cut points for good-quality colostrum are not well-established. People often use dairy values (about 22 per cent), which is considered good in dairy but not sufficient for beef cows,” says Gamsjaeger.
Gamsjaeger sets colostrum cut points for beef cows at 26 per cent with the Brix. Anything higher, with immunoglobin concentrations of 125 or more, is good-quality beef colostrum. A calf would have to drink three to 3.5 litres within 12 to 24 hours, she adds, which should be easily achievable with a beef calf.
Another option is a hand-held refractometer. A good one runs $100 to $150.
“You put a drop of colostrum on it and hold it against the light and look into the small keyhole to see what percentage you get. There are also digital ones that give you the result in numbers so you don’t have to look through a little hole,” she explains.