Zinc in horses
This article summarises the requirement ranges for zinc in horses.
What it does
Zinc participates in a large number of enzymes, above all where tissue is constantly renewed: skin, mucous membranes, coat and hoof horn. Immune defence draws on it too.
Why it matters
Everything that regrows on a horse depends on this supply. Because hay and grass regularly fall short here, zinc is one of the few items where the calculation almost always pays off.
When it becomes critical
It gets tight from two directions: the forage often supplies too little, and a lot of grain or calcium in the same ration further slows uptake. Undersupply shows as scaly, crusty skin and hair loss. Towards the top the margin is wide — surpluses are unproblematic.
How much a horse needs
Maintenance: 423 mg daily at 500 kg, equivalent to 30–40 mg per kg of feed dry matter. Since forage rarely manages that alone, zinc is part of nearly every supplement.
Involved in numerous enzymes; responsible for skin, mucous membranes, coat and hoof horn; supports the immune system.
Cited values
| Type | Value | Unit / context |
|---|---|---|
| Requirement | 423 | mg/day (maintenance, 500 kg) |
| Requirement | 30 | mg/kg feed DM (maintenance, lower end of range) |
| Requirement | 40 | mg/kg feed DM (maintenance, upper end of range) |
| Requirement | 38.4 | mg/kg feed dry matter (maintenance) |
| Requirement | 48.1 | mg/kg feed dry matter (pregnant) |
| Requirement | 34.1 | mg/kg feed dry matter (lactating) |
| Requirement | 52.2 | mg/kg feed dry matter (growth) |
| Requirement | 37.2 | mg/kg feed dry matter (work) |
| Toxic from | 500 | mg/kg feed DM |
Careful when comparing: the requirement is given **per day**, the upper limit **per kilogram of feed dry matter**. These are different reference bases and cannot be compared directly. The upper limit is also not a target — it is the amount at which harm begins.
Possible deficiency signs
- Crusty, scaly skin and hair loss; a high proportion of cereals or calcium makes absorption even worse.
Interactions
- Zinc ↔ Calcium/cereals (a high proportion impairs zinc absorption)
- Zinc ↔ Copper
- Zinc ↔ Phytic acid (found in cereals, bran and oilseeds; binds zinc in the gut)