Micronutrients can Have Macro Impacts: Trace Minerals Are Crucial for Cattle Health

By Heather Smith Thomas

Minerals are essential nutrients.  Sodium, chlorine and potassium are crucial to maintain fluid balances in the body and blood.  Iron is an important component of red blood cells—enabling them to carry oxygen.  Bone formation and milk production depend on calcium and phosphorus.  Calcium and phosphorus are called macro-minerals because they are required in fairly large amounts.  Deficiency is generally not a problem because these minerals are present in high levels in many feeds.

Other minerals such as copper, iron, iodine, manganese, selenium and zinc are needed in very tiny amounts and are called trace minerals. They are also very important to health.  Adequate levels of copper, zinc, manganese and selenium, for example, are crucial for a healthy immune system and optimum reproduction.  Some soils and plants are short on various minerals, leaving feeds deficient.

For this reason, many livestock producers use supplemental minerals to augment cattle diets.  These are often supplied in salt/mineral mixes, 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 (including certain minerals that may bind with the supplemented mineral) 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. started several research projects in 2009.  There have also been university studies looking at how rapidly injected trace minerals are absorbed and how long they are stored in the liver.  Other studies have evaluated performance of shipping-stressed cattle receiving injected minerals versus performance of cattle that did not receive it, effects on calf health and reproductive performance when injecting cows before and after calving, and how trace mineral status affects respiratory risk and finishing performance in beef steers.

We now know that trace minerals are crucially important in cattle health, from conception through harvest and all along the way in the reproductive life of cows and bulls.  “If we look at the immediate deficiency issues that a calf might face after birth, they actually originate during the last 90 days (or even earlier) of the cow’s pregnancy.  This is when the fetus is growing fast and getting a lot bigger, and also the period of time when most of the trace minerals are being transferred to the calf from the cow (to be stored in the calf’s liver), for that calf’s early life.  Many of the deficiency problems that we see in a newborn calf, like white muscle disease, actually started 90 days earlier because the cow was deficient.  If the cow didn’t have adequate trace minerals in late pregnancy there are several problems we might see, even before she gets to the next breeding cycle,” he says.

Minerals are needed at a certain level, every day, so we need to find ways to make sure they are available to cattle every day.  If for some reason you can’t put out a mineral supplement, these levels will decline in the cattle.  If you are not providing trace minerals, they will run short at some point in time.  The flip side of this is that cattle don’t need the same level every day.  There are some times in their production cycle that they need more, so producers need to be aware of those times, and be prepared to supply more during those times.  The main times a cow needs more trace minerals is 30 to 90 days before she calves, and 30 to 60 days before breeding—to give her the utmost chance to conceive and keep the embryo alive.

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 you can’t provide a mineral supplement at those times (such as prior to calving and prior to breeding) or are not sure the cows are consuming adequate amounts, an injectable product can make sure that they are taken care of.

SELENIUM – “The most common mineral deficiency we see in the U.S. that impacts young calves is selenium.  Selenium imbalance in the cow during the last 90 days of gestation can cause several different problems.  If deficiency is very severe, we see white muscle disease in the calves.  Their muscle tone is poor and they are unable to get up, and they don’t suckle.  If you pull on the calf’s tongue you can often feel that it is weak and the calf doesn’t pull it back aggressively,” says Havenga.  If deficiency is that severe, very often the cow suffers from retained placenta, which may impact her ability to recover quickly from calving and rebreed on schedule.

If the deficiency isn’t quite that severe, the cow may not have a retained placenta, but because she doesn’t have enough selenium to keep her immune system strong, she may end up with a low-grade uterine infection.  “This will also impair her reproductive efficiency and may make her slower to rebreed.  Her calf will not have white muscle disease, but may have a dysfunctional immune system, and may be more prone to scours or respiratory disease,” he explains.

In the last 90 days of gestation the cow is also creating colostrum.  “It needs to contain the antibodies necessary to protect the calf during his first weeks of life.  If the cow is low in selenium she produces a lower quality colostrum, which also impacts the calf’s immune system and he will be more prone to disease,” says Havenga.

ZINC – “Some researchers have found that if the cow is low in zinc in the period just prior to calving, she may have a longer than normal gestation.  The signaling of the calf to be born is weaker in that cow.  Producers sometimes tell me that ‘this year was a little odd, with a few cows that carried their calves much longer and had really big calves that we had to pull, which is something we don’t normally do.’  This is just a subtle change, but deficiency in zinc can contribute to this,” he says.

The impact on the calf is a little different.  “Very low zinc in the calf will cause dandruff.  Skin quality is poor, and that calf will also have a much poorer response to vaccination.”  The calf is unable to mount strong immunity.

COPPER – This important trace mineral works hand in hand with selenium and can be a contributing cause to retained placenta in the cow.  “If copper is very low, cows will be slow to clean, and this deficiency is also very detrimental to the calf’s immune system.  The calf will be very susceptible to scours, and to a lesser degree susceptible to respiratory disease,” he says.

“If the fetus was low in copper for a long time, and then after birth the calf is still low in copper, one of the things that we see here, especially on the border between Colorado and Nebraska and Wyoming is abomasum ulcers.  The calf will drink milk and then get sores and holes in the abomasum.  This has been linked to structural weakness in the connective tissue of the gut.  It can’t stretch and contract properly.  Every time the calf gets a belly full of milk, the stomach stretches and then it tears a little bit.  Those little tears eventually become infected, since there are always some bacteria in the gut.  Every time the calf nibbles on something, bacteria are also ingested.  Soon there are some open sores within the gut, which may eventually perforate, killing the calf,” he says.

Copper deficiency can also lead to fragile bones and more fractures.  “There are several minerals that play a role in early development of bone.  The bones have two different components—a scaffolding that gives structure, and calcification that makes it strong and hard.  The scaffolding is a combination of 3 different minerals—manganese, copper and zinc.  If that scaffolding is out of whack, we see bones that become very brittle and break easily, or joints that become bigger/wider.  This is because the scaffolding is collapsing.  It’s like taking a piece of clay and pushing down on it, making it bulge outward,” says Havenga.

MANGANESE – This element is also important for strong bones, strong immune system, and for hormone production in cows and bulls.  For instance, progesterone levels in the pregnant cow are dependent on adequate manganese.

SECONDARY DEFICIENCIES – “In the Midwest this past year researchers at Iowa State University saw some herds of beef cattle with calves that looked like little dwarfs.  They were very small but all their joints were enlarged and they had contracted tendons.  The veterinarians found that these calves were very low in manganese.  When they looked at the history of these calves they discovered that this was a secondary deficiency due to too much iron in the silage the cattle had been fed.  The iron tied up the manganese in the diet,” says Havenga.

“When we look at why some of these problems occur, it could either be due to a primary or secondary deficiency.  A primary deficiency is when the body simply does not have enough of that mineral.  We are either not putting enough selenium, copper or zinc in the diet and the feeds are deficient, or there are other reasons for cattle not consuming the correct amount” he explains.

Dr. Stephanie Hansen, Associate Professor, Beef Feedlot Nutrition Chair, Iowa State University Hansen was part of the research team that looked at the manganese deficiency in calves in the Midwest.  She earlier did her masters work at North Carolina State University on effects of manganese deficiency and reproduction in beef heifers.  “Those heifers were still able to get bred, and have normal pregnancies, but when they calved, many of their calves exhibited classical signs of manganese deficiency.

“It looked like someone punched those calves in the nose; it was shorter than normal.  The nose is made of cartilage, and manganese is crucial to cartilage formation.  Those calves had underdeveloped nasal passages so their noses were not as long as in a normal calf, and this made it look like their lower jaw was too long.  Actually the lower jaw was normal; the nose was too small,” she says.

The manganese-deficient calves were also shorter in height because manganese is important in bone formation.  “Gestation is a critical time for manganese to be adequate, because the fetus is growing so rapidly.  Bone development and cartilage formation requires adequate levels of manganese,” Hansen explains.

Some of the calves born in her study were like disproportionate dwarfs.  “We had some 50-pound calves born from 1400-pound cows, which was very unusual.”  This was the first time that anyone had created manganese deficiency under research conditions.

“Then last spring I got multiple phone calls from veterinarians and other folks in Iowa and surrounding states saying they had calves that looked manganese deficient.  I was surprised, because we don’t see this very often.  We found extensive incidence of manganese deficiency in the Mid-west this last spring, largely in cattle that had been fed corn silage almost exclusively over the winter,” she says.

The corn silage was contaminated with soil, and the iron becomes very available during silage fermentation.  “Iron competes with manganese for absorption in the body, and that was why heifers in my masters project were so manganese deficient.  We had high soil levels in our corn silage–about 700 parts per million of iron, which is greatly above cattle requirement for iron.  Iron and manganese use the same transporter in the gut and were competing for absorption.  Manganese deficiency is more likely to come from high iron levels than from a manganese-deficient diet,” she explains.

“In the past few years we’ve seen an increase in secondary deficiencies—where there is enough manganese or copper or selenium in the diet but something else is tying it up,” says Havenga.  Molybdenum occurs in many soils and has always been in the grasses, so why is this problem getting worse now?

“The reason may be that certain new supplements have become very affordable such as distillers cubes that are high in protein.  The problem is that distillers grains also contain a lot of sulfur.  As soon as we combine sulfur with molybdenum we reduce copper uptake by the body—by more than 50%.  Because these other feed products have become available and affordable, we see some other problems,” he says.

Producers need to look at the whole picture and assess all parts of the diet.  If some ingredients bring with them molybdenum, sulfur or high levels of iron, producers need to be aware that this could skew the mineral balance by tying up important trace minerals, reducing the amounts absorbed by the animal.

“This is why we developed Multimin®90 (an injectable trace mineral product) because it is the one technology that by-passes the gut completely.  Producers can strategically use it when their animals need a little more, and by-pass the gut and not have to worry about things that will interfere,” he says.  The injectable product is administered by giving a certain amount of milliliters per body weight and age and is good insurance that each animal gets what it needs.

When a producer depends entirely on ingested supplements there will be variable results because some cattle won’t consume them.  “When we’ve done liver biopsies to check mineral levels, we find vast differences in cows—in the same herd, on the same ranch.  There may be anywhere from a 25 to 45% difference between the lowest and the highest levels.  The average may be good, but some individuals may not eat the supplement and some will eat too much,” he says.

SIDEBAR: EARLY LIFE OF A CALF – “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.

SIDEBAR: PROTECTING THE COW – “If we look at the 85-day window between calving and rebreeding—when we want the cow to start cycling, conceive, and grow the embryo—the key period is 30 to 60 days before the start of breeding season.  If we can do anything in that 30 to 60-day window to improve the cows’ mineral status, we will see acceptable pregnancy rates.  This can be done by putting a good chelated mineral in front of those cows, or injecting them with trace minerals,” says Havenga.

“If cows can be adequately supplemented in that 30 to 60-day window, research shows two big benefits for the producer.  We actually get more cows to breed back and we’ll have more calves in the next calving season.  It may not be a phenomenal number, maybe just 3 to 6%, but there will be more cows conceive,” he says.

“The second thing we see, with good mineral intervention during that window, is a significant change in how those cows conceive; more of them will conceive early in the breeding season.  This is very beneficial because those cows will wean off heavier calves since they have more days to grow.  On top of that, those cows will have more days to recover from calving and be ready for the next breeding season.  If cows are calving in the very last days of calving season, some of them won’t breed back on time and will be open, unless you extend the breeding season,” he explains.

The biggest benefit is not just getting more cows bred, but that they breed early.  “If you look at the dollars, a cow makes you the most money if she stays in the herd so you don’t have to buy or develop a replacement for her (because that’s very expensive) and if she calves early.  Having that extra 20 to 40 days on the ground, the calves that are born early are heavier than the late-born calves and make you more money,” he says.

Cows need mineral supplementation in that window before breeding season for two reasons.  “If we put semen into healthy cycling cows at the right time, 90% or more will conceive, but some will resorb that embryo in the first 42 days because they don’t have enough antioxidants to protect the early embryo (or if any other metabolic imbalances exist).  If we look at the antioxidants that a cow uses to protect that embryo, she relies on 5 key trace minerals—selenium, copper, zinc, manganese and iron.  Iron is the one we don’t have to worry about because there is enough iron in our soils that we rarely see iron deficiency in cattle,” he says.

The other trace minerals are critically important, however, and we need to make sure we have enough of them in the cow on the day she is bred.  “This is why we start paying attention and giving her a supplement 30 to 60 days before she is bred.  If we start on the day we turn the cows out with the bulls, we have missed that window and are probably 30 to 60 days late.”

SIDEBAR: HORMONE PRODUCTION – Trace minerals play a key role in hormone production.  “When a cow becomes pregnant, the hormone that keeps the fetus alive is progesterone.  Production of this hormone is regulated by the level of manganese in that cow.  If she is deficient in manganese she may be at risk of not producing enough progesterone to maintain the pregnancy,” says Havenga.

Bulls also need adequate hormones, such as testosterone, to be fertile and do their job breeding cows.  “Producers also need to supplement their bulls with trace minerals in the 45 to 60-day window before we turn them out with the cows.  If we neglect the bulls they may not perform as well.  Testosterone production and sperm production rely on manganese, zinc and copper.  Selenium also plays a role in sperm production but is not a key player in hormone production,” he says.

It’s important to pay attention to the mineral status of bulls because they are slightly more important than the cows.  Each cow will produce one calf, while a bull may sire multiple calves.

SIDEBAR: MACRO MINERALS – There are three macro minerals (needed in larger amounts than the trace minerals) that are very important for cattle—phosphorus, calcium and magnesium.  “Phosphorus plays a large role in reproductive efficiency in beef cows, and in conjunction with calcium plays a major role in bone development.  If a cow does not have adequate calcium reserves when she approaches calving, she may suffer milk fever when she calves,” says Havenga. “Magnesium deficiency is a little different because it is more of a ‘green grass’ disease; cows may end up with grass tetany when forages are very low in magnesium.”