Copper
What it does
Copper is required when blood is formed, pigment is deposited or connective tissue is built. Firm horn, load-bearing tendons and ligaments and an orderly bone metabolism all depend on it.
Why it matters
Wherever tissue has to be firm and elastic at once, copper is involved. In rations for pregnant mares and growing horses this item pays into structures that are meant to last for years.
When it becomes critical
Forage often brings little copper along, which is why breeding-mare and foal rations in particular stay below requirement. Undersupply can show as a lightened coat and as problems in connective tissue and skeleton. Copper is well tolerated; only permanently very high doses burden the liver.
How much a horse needs
Maintenance amounts to about 106 mg a day for a 500 kg horse; measured against dry matter that is 8–10 mg in every kilogram. Where a mare is carrying or a youngster is growing, plan at the upper end.
A building block of enzymes for connective tissue, bone, blood formation and coat colour. It is assessed together with zinc, because the two compete for the same absorption pathways.
Cited values
| Type | Value | Unit / context |
|---|---|---|
| Requirement | 32 | mg/day (maintenance, 100 kg BM) |
| Requirement | 53 | mg/day (maintenance, 200 kg BM) |
| Requirement | 72 | mg/day (maintenance, 300 kg BM) |
| Requirement | 89 | mg/day (maintenance, 400 kg BM) |
| Requirement | 106 | mg/day (maintenance, 500 kg BM) |
| Requirement | 121 | mg/day (maintenance, 600 kg BM) |
| Requirement | 136 | mg/day (maintenance, 700 kg BM) |
| Requirement | 150 | mg/day (maintenance, 800 kg BM) |
| Stricter already from | 50 | mg/kg feed DM (note: above this, the liver can be strained and the use of zinc impaired) |
| Toxic from | 250 | 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.
For foals, horses with liver disease, this value should be applied more strictly — there is no separate figure for these groups. Which value fits in a specific case is worked out in the analysis.
Possible deficiency signs
- A faded, dull coat and brittle hoof horn.
- In foals, disorders of bone and cartilage development.
Interactions
- Copper ↔ Molybdenum
- Copper ↔ Sulphur
- Copper ↔ Calcium
- Copper ↔ Iron
- Copper ↔ Zinc
- Copper ↔ Cadmium
- Copper ↔ Silver
- Copper ↔ Phytic acid