Mineral nutrition plays a critical role in cattle growth and performance. From appetite to milk production and even fertility minerals are needed for proper animal function. If cow-calf performance is lacking in your herd, mineral deficiencies can often be the culprit.
Mineral nutrition can be broken down into two groups – macro and micro minerals.
The seven macro minerals that matter most in a cow’s diet include: potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), sodium (Na) and chlorine (Cl)
The six trace minerals that matter most in a cow’s diet include: cobalt (Co), copper (Cu), iodine (I), manganese (Mn), selenium (Se) and zinc (Zn).
Avoid Common Mineral Supplement Mistakes
Most mineral supplements are formulated incorrectly because they don’t account for forage mineral levels and bioavailability to the animal.
Forage mineral levels account for the macro and micro minerals already in a herd’s basal diet like forage and pasture based on region, time of year, rainfall, etc. For example, early spring pastures are rich in potassium which can interfere with magnesium absorption and can cause complications like grass tetany.
The bioavailability of minerals refers to how efficiently an animal utilizes an element as well as the bioavailability of other elements. For example, if a mineral is formulated with too much potassium it can interfere with magnesium absorption. Most minerals source a highly variable and unavailable form of magnesium that doesn’t balance this ratio making the deficiency worse.
Common Mineral Deficiencies in Cattle
Trace minerals for cattle
Trace minerals are essential elements that are required only in small quantities by cattle. These minerals are critical to the health and well-being of cows, with deficiencies leading to significant health problems.
Copper, zinc, manganese and selenium are some of the most important trace minerals required by cattle. They play a critical role in the proper functioning of various physiological processes, including enzyme activation, immune system response and skin and hair health.
To ensure trace minerals are properly broken down by an animal, the source of trace minerals matters. The structure or bond that holds trace minerals together determines where and when a trace mineral becomes available in a cow’s digestive tract.
The four most common trace mineral sources are sulfate, oxide, hydroxychloride and organic.
Sulfate trace minerals are very water soluble and loosely bonded causing them to break down in the rumen and cause antimicrobial activity to occur. This can impact forage digestibility, energy production, body condition scores and performance.
Oxide trace minerals are generally lower and more variable in bioavailability in the animal because the bonds are incredibly strong and hard for the animal to break down. However, Zn and Mg can have reasonable bioavailability in this form.
Organic trace minerals are bonded to amino acids, peptides and proteins that will bypass the rumen and absorb later in the digestive tract.
Hydroxychloride trace minerals have a unique property that allows them to bypass the rumen and be absorbed more effectively by animals. Although they're technically in an inorganic form, they share the same bond structure (covalent) as organic forms which prevents breakdown by rumen microbes.
Make sure to consult with a ruminant nutritionist to ensure your herd's mineral formulation is properly balanced. It's also crucial to understand how to interpret a mineral tag to ensure the accuracy of the trace mineral source and levels for your herd.
Understanding mineral interactions in cattle
As stated before, the bioavailability of a mineral refers to how efficiently an animal utilizes an element as well as the bioavailability of other elements.
In simple terms, the bioavailability of a mineral determines how effectively an animal can use it, along with other minerals. When the balance of minerals is off, it can limit the availability of another mineral. In cattle, common mineral interactions that limit bioavailability are between calcium and phosphorus, magnesium and potassium and various trace minerals.
Calcium and phosphorus (Ca:P)
Calcium plays a vital role in the health of beef cattle, as it’s needed for various functions in the body and is a key component of the skeleton. The skeleton not only provides structure but also acts as a storage site for calcium.
Both phosphorus and calcium are essential for the formation of bones. In fact, more than 80% of the body's phosphorus is found in bones and teeth. Additionally, 99% of the total calcium in the body is also located in these important structures.
The ideal ratios for Ca:P in the diet are 2:1. If the ratio becomes inverted and more phosphorus is supplemented (or more phosphorus is available in the forage) calcium absorption will decrease. An imbalance in the total diet Ca:P ratio can result in urinary calculi known to ranchers as ‘water belly’ most common in higher grain diets. A long-term deficiency in younger calves and cattle can also severely impact bone growth and lifelong performance efficiency.
Calcium is very cheap and therefore over-supplemented in many minerals. Taken to extremes, this can inhibit the absorption of phosphorus which is one the most expensive minerals in a free choice supplement. Phosphorus-deficient animals can look malnourished and have reproduction problems.
The key to avoiding this negative mineral interaction is knowing the levels of calcium and phosphorus in forages and formulating a custom mineral according to the time of year and quality of pasture.
Most minerals over supplement calcium even though it’s at adequate levels in forages. Too much calcium inhibits the absorption of expensive minerals like phosphorus.
Magnesium and potassium (Mg:K)
Potassium is the third most abundant mineral in the body. It’s important for acid-base balance, regulating osmotic pressure and water balance, contracting muscles, nerve impulses and even certain enzyme reactions.
Signs of potassium deficiency in cattle include reduced feed intake and weight gain, pica (chewing and gnawing wood and other objects) rough haircoat and muscular weakness.
When forage is growing and immature, potassium concentration is high and typically exceeds the requirements of cattle.
Magnesium is closely related to calcium and phosphorus in function and distribution in the body. This mineral is known to activate many different enzymes. Magnesium is essential in energy metabolism, transmission of DNA, membrane transportation and nerve impulse transmissions.
Signs of magnesium deficiency in cattle include excitability, anorexia, convulsions and muscular twitching, profuse salivation and grass tetany.
Most forages have low magnesium availability (~16% available). Therefore, some source of supplemental magnesium is usually needed.
Too much potassium can interfere with magnesium absorption and cause grass tetany. Most minerals source a highly variable and unavailable form of magnesium that doesn’t balance this ratio.
The importance of salt in cattle mineral
Both sodium and chloride, elements of salt, are essential nutrients for virtually all forms of life. Sodium and chloride are necessary for proper nervous and muscular function, body pH regulation and water retention.
Uniquely, salt may be the only mineral compound animals develop a craving for. Cattle will consume more salt when needed when it’s supplied free choice.
Cattle deficient in salt often eat dirt, manure and urine to satisfy their appetite for salt. This condition, known as pica, can result in reduced feed intake, growth and milk production.
The right mineral will take advantage of this salt craving. While animals crave salt, at high levels it will also deter intake and stop overconsumption of minerals. Producers can use this craving to manage (limit) the intake of mineral. A mineral with between 20-25% salt is a good target to help ensure correct mineral consumption and also meet salt requirements.
Understanding mineral toxicity in cattle
Following the suggested feeding directions on a mineral tag is incredibly important. While too little mineral is often discussed as a deficiency, in some cases, overconsumption can also be toxic.
According to the National Research Council Nutrient Requirements of Beef Cattle, the guidelines for the maximum levels of salt and eight individual minerals were identified as being of frequent concern for toxicity in cattle. These include cadmium, copper, fluorine, lead, mercury, molybdenum, selenium and sulfur. Along with calcium, phosphorus and potassium were identified as being of occasional concern for toxicity.
Mineral toxicity: maximum mineral requirements for cattle
Growing and Finishing Cattle
Sodium Chloride, %
4.5 (growing animals) 3.0 (lactating cows)
0.3 (high concentrate diets)
0.5 (high roughage diets)
Source: National Research Council Nutrient Requirements of Beef Cattle
Essential vitamins for cows
Vitamins are also essential for growth, health, reproduction and survival for all classes of livestock.
Vitamin needs of cattle can be confined largely to A, D and E. This is because bacteria in the rumen of cattle are considered to have the ability to synthesize vitamin K and B vitamins in sufficient quantities to meet cattle requirements.
Vitamins A, D and E must be obtained from their environment because cattle can’t produce adequate quantities on their own.
A normal misconception about vitamin levels is that more is always better. But that isn’t necessarily the truth. It’s more important to understand the vitamin levels in your herd’s basal forage diet and supplement the right quantities in your mineral. Too many vitamins, and they’ll be wasted. Too little, and your herd could be at risk of deficiencies.
The best way to avoid this is to understand how to read a mineral tag and know the general vitamin requirements your herd needs based on each stage of production.
Overall, while vitamins are important, comparing mineral supplements based solely on vitamin levels and assuming one mineral is better than the other because of this is not the best evaluation criteria for your herd.
Mineral intake tips
One of the best mineral management tips is to keep minerals fresh by controlling intake. To improve or limit intake add salt (as stated earlier) or put out a week’s worth of minerals out at a time. If animals are under consuming mineral, try moving its location closer to water sources, under shade or other easy-access areas.
Additionally, make sure to remove any other sources of salt to force animals to eat the mineral and satisfy their dietary cravings. Other sources of salt can include forage or water.
The most important mineral management tip is measurement. Make sure you’re getting a headcount that accounts for all your cows and calves. For example, your late summer/mid-summer mineral consumption might be higher because a 300-400 lb. calf is eating that mineral too. It’s recommended to figure an extra ounce for each calf when you’re taking a headcount.
Lastly, don’t determine the success or failure of mineral intake based on 1-2 weeks. Give each strategy 3-4 weeks and measure the trend. It might take some guessing and checking but eventually, you’ll determine the right management strategy and intake levels for your herd.
To learn more about mineral nutrition, check out this webinar by a Ralco Ruminant Nutritionist below.
Let us help you build a custom mineral program specific to your herd’s unique mineral requirements. Get started today by directly contacting Ralco’s ruminant nutritionist, Dr. Jeff Hill, by calling 507-337-6916 or emailing RuminantHelp@RalcoAgriculture.com.