Nutrition is critical to herd health. Getting the right balance of mineral supplements can improve productivity and reduce health problems.
The right mineral program can help cattle producers improve overall health and even cut costs. Yet, getting it right is a balance. Too little supplementation risks growth and puts cattle at risk for disease. Too much supplement may waste money – or worse, even lead to toxicity.
There are two major categories of mineral supplementation: macronutrients and trace minerals. Macronutrients are required by the animal in high quantities. Trace minerals are required in small quantities but are still critical.
The macronutrients producers most often need to supplement are calcium, phosphorus, potassium, sodium, chloride and magnesium. In addition, there are about eight trace minerals critical to cattle: copper, selenium, zinc, manganese, iodine, iron, chromium and cobalt.
For breeding livestock, there are two critical points when cattle need optimal mineral levels. The first is the month before breeding. It takes about four weeks, or longer, to build adequate stores of minerals. After breeding, the stores help protect the embryo and keep it alive.
“The months prior to breeding are really when we need to pay attention and get the correct levels in there,” says Lourens Havenga, DVM, CEO at Multimin USA, Inc. “With proper mineral levels, we’ll see more cows get pregnant and get them pregnant earlier in the breeding season.”
About 90 days before calving is another critical point. At this time, the animal is transferring her own mineral into the calf. The cow’s milk provides very little trace mineral. Therefore, it’s important to provide adequate levels of copper, zinc and selenium before birth.
“The cow will stack the calf to her own detriment,” Havenga says. “She will deplete her own store. If they’ve depleted themselves, you’ll see retained placentas and uterine infections – both in dairy and beef cattle.”
If the calf is low in minerals, producers will see increased rates of scours and respiratory disease. In addition, the calf may not respond as well to vaccines if the deficiencies aren’t overcome by weaning time.
“A majority of calves weaned are low in copper, zinc and selenium,” he says.
Calcium is the most important macronutrient for cows and calves to receive, says Kent Tjardes, Ph.D., cattle consultant with Purina Animal Nutrition. Calcium plays a critical role in milk production and bone development. It is the most abundant mineral in the body, but cattle generally get plenty of calcium through feed.
“Most grasses provide adequate amounts of calcium, so unless they are grazing on dormant grass and forages, like corn stalks, or using feeding a lot of distiller’s or grains, you will not see a deficiency,” he says.
Phosphorus is another macronutrient that helps with bone development and formation. It’s present in every cell of the body, is part of the genetic material, and is important for the formation of ADP, which is the fuel cell of all animals,
Tjardes says.“With cattle, we rely a lot on bacteria to help break down forages,” he says. “The bacteria in of their cell wall, genetic cattle require phosphorus as part material and their ADP formation as well.”
Reasons for deficiencies
Even producers feeding high-quality feedstuffs will need to supplement some vitamins and minerals. Deficiencies can occur even if cattle are fed the right amount of macronutrients and trace minerals.
“The reason we have imbalances on the trace mineral side is usually due to two different reasons. The first problem is because our forages are deficient,” Havenga says. “The next problem is antagonism – something else in the diet ties up this mineral and prevents absorption. We may supply the mineral through the mouth, but something else in the diet will tie it up and take it out the backside.”
For example, while iron is a critical mineral for cattle, it is rarely a candidate for supplementation. Iron is present in soils and plants worldwide, but can bind up other minerals if there is too much in the animal’s diet.
Molybdenum is another antagonist that will bind to copper and prevent absorption by the animal. It is often found in forages. Sulfur also is an antagonist to copper, zinc, selenium and manganese. Some regions – like Sulfur Springs, Texas – are known for their high-sulfate water, which is a typical culprit.
“Molasses is one of the byproducts that is used in rations to help make them more palatable and is a good binding agent. Unfortunately, molasses also has a high sulfur content,” Havenga says.
Distiller’s byproducts can offer cattle producers an affordable ration ingredient that is high in protein and phosphorus, but it can also come with a high sulfur content, which can bind up the supplemented copper, zinc and manganese.
“It’s one of the reasons we keep seeing imbalances." he says. “It’s not that people are doing a bad job at supplementing. It’s purely because of the variability in forages and that they invariably bring something else in there. It’s the biggest reason we don’t see consistent results.”
Magnesium is a macronutrient that is critical to milk production, bone formation and neuromuscular transmissions, but nitrogen and potassium can be antagonistic to magnesium, causing deficiencies and even disease.
“A lot of times, we have spring calving cows that are turned out on lush grass, and that’s where we get grass tetany, from those high levels of soluble nitrogen in the grass that causes them not to absorb magnesium,” Tjardes says.
It may not be necessary to develop a completely customized mineral program. Tjardes suggests looking at formulations suited to the region to help target some of these concerns.
Accounting for variability
Even if a ration is balanced perfectly, variability in cattle’s feed intake is another reason why supplementing can be tricky, Havenga notes.
“There is, on average, a 30 percent variation between individuals in a group,” he says. “If you offer free choice feed in a bunk and leave cattle to eat as they want, the difference between the lowest and highest intake will be a 30 percent differential. Some animals will eat too little, some will eat too much. That costs us money.”
For grazing cattle, only offering supplements through the ration can cause even more variability. Producers will often see feed refusals increase as quality of grass increases.
Even in these circumstances, producers should not remove access to oral trace minerals.
“There are big seasonal changes,” Havenga notes. “As soon as it rains, and they have good quality green grass, they are like kids – they want to go after the candy. People should not remove access to oral trace minerals. Animals need it on a daily basis, but they don’t need it at the same level every day.”
Technology can help producers balance the cattle’s requirements. Chelated or hydroxy minerals are able to bypass some binding effects, which makes the nutrients more available to the animal.
For selenium, producers can also use organic forms to make it more available. Selenium is an important antioxidant that can work in concert with Vitamin E to prevent metabolic stress, which can cause tissues to break down.
Specific regions, such as the Great Lakes and coastal areas are known to have selenium de ciencies and supplementing with an organic form can be worthwhile, Tjardes suggests. However, in areas of the Dakotas and Wyoming, the levels in selenium in forages can be potentially toxic and you do not want to supplement.
“You don’t want to test forages for selenium all the time because that one mineral is very costly to test for,” he says. “But if you have problems due to either deficiencies or toxicities, it’s a worthwhile investment.”
Key macronutrients: calcium, phosphorus and magnesium
Key trace minerals: copper, selenium, zinc, manganese, iodine, iron, chromium
Reasons for deficiencies: forages low in essential nutrients or high in antagonistic nutrients that bind nutrients and don’t allow absorption.
“To bypass antagonists completely, we can change the route we provide trace minerals,” Havenga says. “Everything that goes through the mouth is going to be exposed to antagonists.”
Recently, injectable trace minerals offer producers another way to supplement cattle without the risk of antagonists.
While injectable minerals have long been used to prevent or treat specific cases of disease, such as iron anemia, injectables have evolved to include a range of supplements.
“On coastal belts where we see a lot of White Muscle Disease, those areas are horrendously low in selenium,” Havenga says. “In the last eight to 10 years, a lot of research has gone into doing multiple minerals in the same bottle. Then, injecting and timing it perfectly for when the animal needs more. Animals need them to reproduce optimally and maintain health at optimal levels.”
Tjardes recommends producers consider how they feed free-choice mineral supplements. Some weatherization helps protect against wind and rain, both of which contribute to wasted input costs. Feeding cubes or protein tubs to provide your sole source of supplemental mineral is often not as consistent, which is another key delivery concern.
“The result of a good supplementation program is in weaned pounds.” – Lourens Havenga, DVM
“The key with mineral supplementation is that they need it all the time,” he says.
To find deficiencies, producers can spend a lot of money analyzing waters, grasses, soils and even requesting liver biopsies on cattle. However, the availability of nutrients and concentrations in plants change over time.
“Forages from a specific location in a pasture or range change,” Tjardes notes. “You can try to customize mineral based on forage analysis, but what you have today is not what you may have a week later. It changes from pasture to pasture and year to year based on moisture and what plants are growing at the time the sample was taken.”
An analysis can give producers an overall look at what kind of antagonists are present and gives a baseline, but specific levels can vary so much that it is very difficult to be confident you have the correct custom formulation to meet or exceed the requirements, Tjardes says.
Producers should check with the updated Nutrient Requirements for Beef Cattle (NRC) recommendations, Havenga says.
However, he cautions against undersupplementing or over-supplementing.
“People are not sticking to scientific data and either overdoing it or underdoing it,” he says. “Make sure you’re following NRC recommendations in your supplement and use only a single balanced oral supplement, critical not to exceed levels for copper and selenium. When using injectable vitamins and minerals, which have an established dose, people often say, ‘well, I looked at the calves, and they looked thin and scrawny. This bottle says 5 cc, but I’m going to give them 15.’ This can result in gross overdose and deaths. Because a little bit is good, that never implies that a lot is better.”
In addition to health risks, overdoing supplementation is expensive, he notes.
Getting supplements right can pay off for producers, Havenga says. Proper supplementation of breeding livestock can result in more effective AI programs and reduced numbers of problems like retained placentas and mastitis.
Getting cattle bred more quickly can help ensure more calves born earlier in the calving season, which can equal a 50- to 80-pound advantage on the calf at sale day, Havenga says.
“The result of a good supplementation program is in weaned pounds,” he notes.
For feedyards, supplementation can pay off in higher quality carcasses. Deficiencies can also result in depressed appetites, poor growth and reduced feed conversion ratios.
“Veterinarians have become more and more involved with this,” he says. “All injectable minerals are prescribed products so it’s definitely something we need to talk to vets about.”