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Trace Minerals for Cattle: How to Identify the Best Source

Trace Minerals for Cattle: How to Identify the Best Source

Are you searching for the best source of trace minerals for your cattle? When it comes to trace minerals such as zinc, hydrochloride or organic forms are regarded as the top choices. In contrast, oxides and sulfates are considered less effective options and can actually damage cattle performance.

In this article, we'll delve into the various trace mineral sources and discuss the advantages and disadvantages of each so you can determine the best trace minerals for your herd.

Understanding trace mineral source

Trace mineral source refers to the structure or bond that holds minerals together and determines where and when trace minerals become absorbed in an animal’s digestive tract.

Here are the 4 most common trace mineral sources:

  1. Sulfates are very water soluble and loosely bonded together causing them to break down in the rumen. This can result in antimicrobial activity to occur in the rumen with some trace minerals, impacting forage digestibility, energy production, body condition scores, performance and more.

  2. Oxides are generally lower in bioavailability in the animal because the bonds are incredibly strong and hard for the animal to break down. This is especially true in the case of copper. However, zinc and manganese have fair bioavailability in this form.

  3. Organics are bonded to amino acids, peptides and proteins or any other organic or carbon-containing compound and don’t typically separate in a liquid medium. This provides a better bypass of the rumen and better absorption later in the digestive tract. While not technically always true, these forms are often commonly referred to as chelates.

  4. Hydroxychlorides are technically inorganic but have covalent bonds similar to the organic forms thatcannot be easily broken down by rumen microbes or dissolved in rumen fluid. This way they bypass the rumen and get absorbed more preferentially by the animal.

The best trace mineral source depends on each individual trace mineral. However, typically organic and hydroxychloride minerals are better than sulfates and oxides. These two forms will ensure optimal bioavailability in the animal, and they won’t break down in the rumen.

It’s recommended to always consult with a ruminant nutritionist to ensure the source of your trace minerals are being correctly absorbed by your herd.

Understanding the 6 most important trace minerals

The most important trace minerals in a cow’s diet include copper, zinc, iodine, manganese, selenium and cobalt.

Copper (Cu)

Copper is an important trace mineral involved in hemoglobin formation (transferring oxygen in the blood to the lungs and tissues), iron absorption, connective tissue function (the tissues support and protect organs in the body) and immune function.

Unfortunately, copper status in cattle is very prone to a number of negative mineral interactions, or mineral antagonists. This refers to minerals that can interfere with the bioavailability of copper or other trace minerals like molybdenum, sulfur, iron, and zinc. When the total intake of one of these antagonists is within the normal or adequate intake range, copper status is likely not affected. However, when daily intake of one or more of these antagonists is higher than what is needed, reduced copper absorption can occur. In these cases, copper supplementation must be increased to gradually restore the animal to normal copper status.

Signs of copper deficiency include anemia, reduced growth rate, depigmentation (dulling) of hair and rough hair coat, diarrhea, reduced fertility and maybe the most important reduced immune function.

Mineral supplements should be formulated with a Cu:Zn (copper: zinc) ratio of around 1:3 or 1:4. It should also be mentioned that copper is highly antimicrobial and can limit rumen microbial activity at high levels. Therefore, meeting this requirement while not having too much available in the rumen is important for optimal animal performance.

The best form of copper is hydrochloride in various organic forms while copper sulfates and oxides are the worst forms. Copper Oxide is so unavailable that it provides no real benefit to the animal. Copper Sulfate while fairly bioavailable is also very soluble and is the most negative trace mineral from an anti-microbial perspective. That’s the reason Copper Sulfate is commonly used to treat foot rot!

Zinc (Zn)

Zinc is an essential component of several important metabolic enzymes in cattle, and it serves to activate numerous other enzymes. Enzymes that require zinc are involved in protein, nucleic acid and carbohydrate metabolism as well as enzymes associated with immune function.

Signs of zinc deficiency include reduced feed intake and growth rate, listlessness, excessive salivation, reduced testicular growth, swollen, cracked hooves, skin lesions (parakeratosis), failed or slowed wound healing and reduced fertility in cows and bulls.

Most forages are low in zinc compared to the suggested requirement (30 ppm). However, the forage concentration of zinc appears to not decline as the plant matures.

As previously noted, mineral supplements should contain a copper-to-zinc ratio between 1:3 and 1:4. Like copper, zinc is antimicrobial, and supplementing over this ratio should be avoided.

The best forms of zinc are hydroxychloride and organic forms to avoid a breakdown in rumen fluid and negative effects on the microbial population. Zinc Oxides and Zinc Sulfates are the worst. Zinc Oxide is moderately available and less antimicrobial than Zinc Sulfate.

Iodine (I)

Iodine is an essential component of the thyroid hormones thyroxine (T4) and triiodothyronine (T3), which regulate the rate of energy metabolism in the body. Iodine requirements may be elevated in cattle consuming goitrogenic substances, which interfere with iodine metabolism. These goitrogens impair iodine uptake by the thyroid, and their effect can be overcome by increasing dietary iodine.

Signs of iodine deficiency include swelling of the thyroid gland, particularly in newborns, hairless, weak calves at birth, low reproductive rates in cows and retained placenta. Clinical signs of iodine deficiency may not be apparent for up to one year after the iodine-deficient diet is initiated.

Iodine supplementation is inexpensive and easily provided through iodized salt or via mineral supplementation. Iodine is usually provided in supplements in the form of calcium iodate or ethylenediamine dihydroiodide (EDDI), an organic form of iodine.

Manganese (Mn)

Manganese is important for bone growth and formation in young animals and maintaining optimum fertility in female cattle.

Signs of manganese deficiency include skeletal abnormalities in young cattle resulting in stiffness, enlarged joints, and reduced bone strength, low reproductive performance in mature cattle, abortions, stillbirths and low birth weights.

The necessity for manganese supplementation in grazing cattle remains unclear. Forage and feed manganese concentrations are generally well above the concentration suggested for the dietary requirement of cattle (20 to 40 ppm). However, limited research suggests that the availability of forage manganese is quite low (less than 20%). Until more research is available and considering the importance of manganese in cow fertility and in young calf development, it's recommended to supplement cattle prior to and immediately following calving.

The best manganese sources include manganese sulfate, manganese oxide and various organic forms of manganese. Manganese has limited antimicrobial qualities, so the inorganic or ionic forms are fine for use in ruminant diets.

Selenium (Se)

Selenium is required in the body to break down harmful oxidizing agents. Selenium and vitamin E are somewhat related because vitamin E acts to protect cells from the harmful effects of these oxidizing agents. Vitamin E also acts as an antioxidant. Therefore, a deficiency of either selenium or vitamin E will increase the requirement for the other.

Signs of selenium deficiency include white muscle disease, reproductive failure, increased incidence of retained placenta in cows, increased calf mortality and reduced calf weaning weights and immune suppression.

Sodium selenite is the most common form of selenium supplementation, although several organic forms of selenium have recently been developed.

Finally, unlike many other trace minerals, the range between dietary toxicity and deficiency is quite narrow with selenium. If you’re mixing your own selenium, it can become toxic to cattle at only 10x the recommended amount. Additionally, selenium levels in forage can range from severely deficient to severely toxic, so know what is common in your area. Selenium can often be deficient in newborn calves and the inorganic forms do not cross over in the milk. So, if you’re considering an organic form of Selenium just prior to and into early lactation may be warranted.

Cobalt (Co)

A unique nutritional situation exists in ruminant animals regarding cobalt nutrition. While the ruminant does not have a requirement for elemental cobalt, the rumen microorganisms do.

The microbes in the rumen use cobalt to produce vitamin (B12) which supplies the animal’s requirement for this vitamin. Vitamin B12 is essential for the normal formation of red blood cells and serves as a cofactor for important biological enzymes.

Additionally, a wealth of data suggests that cobalt (more specifically microbes supplemented with cobalt) is important to aid in the breakdown of fiber in the rumen resulting in the release of energy to the animal and gain.

Cobalt sources that are the most bioavailable to the animal include sulfate, carbonate and chloride forms as well as organic forms of cobalt.

Why trace mineral source matters

The unique thing about ruminant animals is that they can obtain most of their energy from grasses and forages.

The reason this is possible is because of a massive fermentation chamber called a rumen, populated with trillions of microbes. These microbes, particularly the bacteria, break down fiber and then ferment it into volatile fatty acids (VFAs) that are absorbed directly from the rumen and utilized as an energy source for the animal.

Great care must be taken to not damage these microbes because any upset with them will affect the fermentation in the rumen and decrease the energy and performance of the animal.

Since the rumen is located at the beginning of the digestive tract, anything the animal consumes must go through the rumen first. This creates a unique challenge in trace mineral supplementation because some trace minerals, particularly copper and zinc, have been shown to be very antimicrobial and impact fiber digestibility. That’s why choosing the correct source of copper and zinc is crucial.

Trace Minerals for Cattle: How to Identify the Best Source

The bottom line, learn how to read your mineral tag so you can choose the best trace mineral sources for your herd. This way, you'll get the most value from your investment and see improvements in your herd's performance.

Let us help you build a custom trace mineral program specific to your herd’s needs. Get started today by calling Ralco’s ruminant nutritionist, Dr. Jeff Hill at 507-337-6916 or emailing


1. Vitamin and Mineral Nutrition of Grazing Cattle Oklahoma State University

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