Zinc and copper deficiency in horses – key trace elements essential for health, coat quality, and hoof condition

Zinc and copper are trace elements that are often deficient in the diets of horses. Their deficiency can weaken the immune system, worsen the condition of the coat and hooves, and even affect fertility. Balanced supplementation is particularly important for working horses, growing horses, and pregnant and lactating mares.

Although zinc and copper are trace elements—meaning they occur in the body in very small amounts—their role in a horse’s health is enormous. They are essential, among other things, for proper hoof and coat growth, tissue regeneration, immune function, and enzyme activity. A horse’s requirement for these elements is relatively low, but the line between an adequate and an excessive amount is very thin. Both deficiency and excess can lead to health problems.

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In practice, mistakes in zinc and copper supplementation usually do not stem from a lack of awareness of their importance, but rather from improper use of mineral additives or the unintentional combination of several products with similar compositions. It should also be remembered that a horse’s body has a limited tolerance for excess trace elements. An overly high intake of one element (e.g. zinc) can hinder the absorption of another (copper), which is why balancing the diet is crucial for the horse’s health and performance.

Zinc (Zn) and copper (Cu) are trace elements that are often lacking in equine diets, especially when horses are fed mainly hay and oats. These deficiencies may not produce obvious symptoms immediately, but over time they affect condition, immunity, coat and hoof quality, as well as fertility.

The role of zinc in the horse’s body

Zinc (Zn) is a trace element most commonly associated with the health of a horse’s skin and coat, but its importance is much broader—it supports the functioning of all tissues, enzymes, and metabolic processes. Zinc deficiency is one of the most frequently observed trace element deficiencies and can affect not only a horse’s appearance and condition, but also its immunity, tissue regeneration, and fertility.

What roles does zinc play in the horse’s body:

– It participates in numerous metabolic and enzymatic processes.
Zinc is a component of many enzymes, including superoxide dismutase, liver dehydrogenases, and alkaline phosphatase. As a result, it is involved in many cellular processes, such as cellular energy metabolism, DNA and RNA replication, and cell division. Its presence is essential for the proper functioning of all tissues.

– It supports the health of the skin, coat, and hooves.
Zinc-dependent enzymes are involved in keratinization, which determines the proper structure of the skin, coat, and hoof horn. Zinc deficiency leads to hyperkeratosis, reduced hardness and strength of the hoof horn, and problems with the skin and coat.

– It is responsible for proper tissue regeneration and immune function.
Zinc supports regenerative processes through its role in cell division and antioxidant enzymes, promoting wound healing, tissue repair, and protection against oxidative stress. Deficiency can slow regeneration and weaken immunity.

– It affects semen quality in stallions and fertility in mares.
In stallions, zinc deficiency can impair semen production and quality; in mares, it can negatively affect successful fertilization and early embryo development. Zinc is therefore important for equine reproduction and breeding.

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Typical signs of zinc deficiency in horses include:

– dull, brittle coat,
– flaky skin,
– brittle, weak hooves,
– slower wound healing.

The importance of copper for horses

Copper is a trace element that supports the formation of red blood cells, strengthens tendons and joints, and is responsible for the natural color of the coat. Copper deficiency can lead to anemia, weakening of connective tissue, and changes in pigmentation, which is why ensuring an adequate copper supply in a horse’s diet is so important.

The role of copper in the horse’s body:

– Essential for the absorption and utilization of iron (prevention of anemia).
Copper is involved in the production of enzymes that are crucial for the transport and utilization of iron, for example in hemoglobin synthesis. In this way, it supports a proper number of red blood cells and helps prevent anemia.

– Participates in the production of collagen and elastin – important for tendons, joints, and blood vessels.
The copper-dependent enzyme lysyl oxidase is responsible for forming cross-links between collagen fibers, which ensures the strength and elasticity of tendons, joints, and blood vessels. Copper deficiency can weaken connective tissue and contribute to musculoskeletal problems.

– Influences coat pigmentation.
Copper is essential for the enzyme tyrosinase, which converts tyrosine into pigments. Copper deficiency may lead to a loss of natural coat color; for example, bay horses may develop a reddish оттенок (tinge) to their coat.

Typical signs of copper deficiency in horses include:

– loss of coat pigmentation,
– joint stiffness and weakened tendons,
– reduced immunity,
– slower growth and development in young horses.

Zinc and copper – balance as a key factor in horse health

Zinc (Zn) and copper (Cu) act in a closely interconnected balance in the horse’s body. An excess of one element can inhibit the absorption of the other, leading to deficiencies despite an apparently adequate dietary supply. Maintaining an optimal Zn:Cu ratio is essential for a horse’s health and condition; it usually ranges from 1:3 to 1:4 or 1:5, depending on the animal’s age, activity level, and health status.

For this reason, supplementation of zinc and copper should be carefully selected and balanced, ideally based on an analysis of hay, forage, or the entire diet. Proper Zn and Cu proportions ensure correct absorption, support the immune system, maintain healthy skin, coat, and hooves, and contribute to the proper development of young horses as well as reproduction in mares and stallions.

How to recognize zinc and copper deficiencies in horses?

Zinc and copper deficiencies often develop subclinically, meaning that symptoms are not immediately visible. Over time, however, they can negatively affect the horse’s condition, immunity, coat and hoof health, and fertility.

How to confirm zinc and copper deficiencies?

– blood and serum tests or hair analysis to assess Zn and Cu concentrations,
– analysis of feeds, hay, and the total diet,
– observation of the condition of the coat, skin, hooves, and the horse’s overall condition.

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How to supplement zinc and copper deficiencies in horses

Zinc and copper deficiencies can be effectively corrected by implementing appropriate dietary support strategies for horses:

– Diet and feed analysis.
Before starting supplementation, it is advisable to assess the Zn and Cu content of hay, forage, and concentrate feeds. This makes it possible to choose the right supplement and avoid an excess of one element that could block the absorption of the other.

– Mineral supplementation.
Chelated forms of zinc and copper (such as gluconates, proteinates, or amino acid complexes) are recommended, as they are well absorbed and safe for horses. Ready-made mineral blends help maintain proper Zn and Cu proportions in the diet.

– Control of the Zn:Cu ratio.
Maintaining an optimal zinc-to-copper ratio in the horse’s diet is crucial; it should range from 1:3 to 1:4 or 1:5, depending on the animal’s age, condition, and health status. Proper proportions ensure correct absorption and utilization of trace elements.

– Monitoring supplementation effects.
Regular observation of the condition of the coat, skin, and hooves, along with blood tests or hair analysis, allows the effectiveness of supplementation to be monitored and doses adjusted if necessary.

– Caution when combining products.
An excess of zinc can lead to copper deficiency, while excess copper may cause hemolysis. Therefore, all mineral supplements should be used cautiously and based on a reliable analysis of the diet.

Summary:
Balanced supplementation of zinc and copper is essential for health, immunity, proper development of young horses, coat and hoof condition, and fertility. With an appropriate diet and regular monitoring of results, you can effectively prevent deficiencies and support your horse’s condition throughout the year.

References

Kędzierski, W., Chałabis-Mazurek, A., Bełkot, Z., Janczarek, I., & Kowalik, S. (2025). Zinc, copper and selenium deficiencies in broodmares in south-eastern Poland. Polish Journal of Veterinary Sciences, 28(3), 475–479. https://doi.org/10.24425/pjvs.2025.156074

Reiwald, D., & Riond, J. L. (2002). Copper and zinc in animal feed for adult horses in Switzerland. Schweizer Archiv für Tierheilkunde, 144(10), 545–548.

Geor, R. J., Harris, P. A., & Coenen, M. (Eds.). (2013). Equine Nutrition: Applied and Clinical. Elsevier.

Wagner, E. L., Potter, G. D., Gibbs, P. G., Eller, E. M., Scott, B. D., Vogelsang, M. M., & Walzem, R. L. (2011). Copper and zinc balance in exercising horses fed two forms of mineral supplements. Journal of Animal Science, 89(3), 722–728. https://doi.org/10.2527/jas.2010-2871

Pilliner, S. (2008). Practical Feeding of Horses and Ponies (J. Sikora, Trans.). Warsaw: Sima WLW.

Meyer, C., & Coene, E. (2001). Horse Nutrition (M. Miękisz, Trans.). Warsaw: PWRiL.