Micronutrients with Macro Impact
Trace minerals can be critical for vaccine response
by Heather Smith Thomas
Minerals are essential nutrients. Adequate levels of certain mineral are generally not a problem because these minerals are present in high levels in many feeds. However, minerals such as copper, iron, iodine, manganese, selenium and zinc are needed in very tiny amounts and are called trace minerals. They are very important to health and are crucial for a healthy immune system and optimum reproduction.
Many livestock producers use supplemental minerals to augment cattle diets. These are often provided free choice. Consumption is varied however, with some animals consuming too much while others eat inadequate amounts or none at all. Also, other aspects of diet may hinder absorption by the body. Because of this variability, some stockmen individually dose their animals by drench, bolus or injection to make sure they directly receive the necessary minerals.
Dr. Lourens Havenga, Chief Executive Officer of Multimin USA, Inc. said it is important to have a good mineral program. “Producers need a day-to-day program, providing adequate supplement, and an additional plan for the periods of increased need. These are not long periods, but they are critical,” he says.
“If we look at a normal, healthy calf from birth to branding age—a calf that had adequate mineral levels at birth—those levels will drop dramatically during that time,” says Havenga.
“There was a really good study done by a graduate student, Christopher Branum, at Texas A&M showing that baby calves from beef cows, with normal mineral levels, by the time they reach 56 days of age have reduced those mineral levels in the liver by about 75%. This happens for two reasons. That calf is growing rapidly, doubling its weight a couple of times between birth and weaning. Rapid growth rate uses a lot of those minerals for building tissue. The second reason is that cow’s milk is very low in trace minerals,” he says. Those particular minerals in the cow’s diet do not come through in her milk.
“There is a very high level of calcium in cow’s milk, but very low levels of copper, selenium, zinc and manganese. So if the calf has low levels at birth (due to deficiencies in the cow during late pregnancy) we run into problems very quickly. He will be growing fast, and become very deficient, very quickly,” says Havenga.
This is why producers are sometimes disappointed with calf vaccine protocols. “We are usually giving calves their first vaccination at branding age which is usually sometime in the first 3 months of life. This is often a time when the calves are very low in trace minerals because they have gone through ¾ of the minerals they were born with. Even if we put a good vaccine into calves that were born from cows that were deficient, it may not be effective,” he says.
When we vaccinate the calf, that animal also uses up more trace minerals in the effort to mount an immune response. “Now we have two things that are happening at the same time—a vaccine response that is inadequate, and won’t produce much protection, and we’ve also sucked a lot of minerals out of that calf to get that poor response—and end up with a calf that’s very susceptible to disease,” he explains.
Some producers call their veterinarian a few weeks after vaccinating their calves and say they think the vaccine was bad because they have a bunch of sick calves. “It’s not because the vaccine was bad, but because the calf was not ready to respond to it. When people ask me if there is one time that’s best to supplement the calf, I have to answer that question a little bit like a politician, by asking them questions. First I ask how their cows came through the winter. If they came through a bad winter or a bad drought, then I would supplement that calf while it is still inside the cow, by giving that cow the proper trace minerals,” says Havenga.
“If the cows came through the winter with adequate minerals (and the calves had good mineral levels at birth), then the one time I would supplement the calves is when we vaccinate them, because we know they will be low in mineral at 70 to 90 days of age. If we vaccinate them at that time, without giving them the trace minerals they need, it’s an injustice to them because they can’t produce a good immune response,” he says.
“Once they respond well to that first vaccine, then all your boosters will be good and the calf will be protected. But if they don’t respond well to that first vaccine, the booster then becomes the first vaccine (and the calf would actually need another booster to be protected).” Since milk won’t have adequate trace minerals for calves, they need supplementation. Calves may sample the mineral you put out for the cows, but are just nibbling and may not consume enough, especially in that first 90 days. The same principle will apply at weaning time when calves are stressed and not eating their oral trace mineral supply. This is why it often helps to put an injectable product into those calves when they are being vaccinated, because then you know that each calf received it—at the right time.