Zinc deficiency
Zinc is involved in the production of skin, wool, hoof horns, male fertility and immune defenses. When it is lacking, the skin thickens and becomes covered with dry crusts, the wool falls out in areas, the horn becomes of poor quality and t...
What is it?
Zinc is involved in the production of skin, wool, hoof horns, male fertility and immune defenses.
When it is lacking, the skin thickens and becomes covered with dry crusts, the wool falls out in areas, the horn becomes of poor quality and the rams become less fertile.
The picture is very suggestive of a contagious skin problem, and this is where the most frequent error occurs: the herd is treated for scabies or ringworm for weeks without results, when the answer is in the bag of feed.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Dry, thick crusts, first around the eyes, nostrils, ears, under the jaw, then on the limbs, scrotum and udder.
Skin that thickens, wrinkles, takes on a rough and sometimes darker appearance, especially in the folds.
Wool that comes off in patches, breaks, leaves bare areas; animals rub against walls and fences.
Itching present but generally moderate, which helps to distinguish it from scabies.
Poor quality hoof horns, which crumble, with dragging lameness and which respond poorly to usual care.
Slowed growth in young animals, animals that decline in status.
In rams: soft testicles, reduced in volume, poor quality sperm, poor mating results. It is sometimes the only sign visible on a farm.
Salivation and lesions around the mouth in some animals, with reduced food intake.
Slow healing of all wounds, including after mowing or trimming.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Insufficient zinc intake in the ration, particularly on fodder from poor soils or on cereal-based rations without mineral supplements.
Blockage of zinc absorption by other elements: excess calcium, high intake of iron or foods rich in fiber, certain well waters. This is the most common cause and the most misleading, because the ration appears correct on paper.
Needs greatly increased in growing young, lactating females and rams preparing for the season.
Digestive diseases and parasitism, which reduce absorption.
A hereditary predisposition to poorly absorb zinc exists in certain animals and is transmitted to offspring; it gives severe forms which return as soon as the supplementation is stopped.
Rations without mineral supplements and trace elements formulated for sheep.
Excess calcium in the ration, particularly through the addition of carbonate or through very rich fodder, which blocks the absorption of zinc.
Poor soils and fodder produced on site, without analysis.
Growing young, lactating ewes, rams preparing to fight.
Animals housed on dry rations for long periods.
Associated digestive parasitism.
Animals from a lineage already affected: the repetition of cases in the same family should raise alarm.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian begins by ruling out contagious causes of skin lesions in sheep, which are common and very similar: scabies, ringworm, ecthyma, photosensitization. A skin scraping and a sample to look for fungi are carried out on this occasion.
He examines several animals from the group and precisely locates the lesions: the distribution around the head, on the limbs and on the scrotum is very evocative.
A blood test allows you to measure zinc, but its interpretation is delicate; the veterinarian completes it by analyzing the ration and fodder, especially looking for elements that block absorption.
In rams, an examination of the semen documents the impact on fertility and provides a monitoring criterion.
A controlled supplementation trial, decided with the veterinarian, often provides the clearest answer: skin lesions improve in a few weeks when the deficiency is indeed the cause.
Treatment
The correction is based on a supply of zinc in a form and quantity determined by the veterinarian, generally by a specific sheep mineral supplement.
No dosage should be improvised: excess zinc in turn creates imbalances, particularly with copper, to which sheep are already very sensitive to variations.
It is essential to correct at the same time what is blocking absorption: reduce excess calcium, review the water source, adapt the ration. Without this, the supplementation remains ineffective and the breeder wrongly concludes that the diagnosis was false.
Skin lesions require local care and hygiene; Established bacterial superinfections may require prescribed treatment.
Lameness linked to a bad horn improves slowly, while a better quality horn grows back: it takes several months.
In rams, fertility takes time to return, as it takes weeks to produce the semen. A ram deficient during fight preparation will not be recovered in time for the season.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Permanently distribute a mineral and trace element supplement intended for sheep, and check that it is consumed.
Have the fodder and water analyzed in the event of repeated skin problems in the herd, also looking at the elements that block absorption and not just the zinc itself.
Avoid excess calcium and unreasonable mineral intake, which do more harm than good.
Strengthen the coverage of needs before the fight in rams and during the growth of the young.
Control digestive parasitism.
Remove from reproduction animals which recur as soon as supplementation is stopped, because a hereditary form is possible.
Do not repeatedly treat scabies or ringworm without diagnosis: this is an unnecessary expense and a delay in treatment.
Possible complications
Long-lasting infertility of rams, with a lost breeding season.
Bacterial superinfection of damaged skin areas.
Persistent lameness due to poor horn quality, with a higher risk of foot rot.
Slowed growth and animals downgraded for sale.
Lost or devalued wool.
Increased sensitivity to all infections, zinc participating in immune defenses.
Poor healing of wounds from shearing, trimming and interventions.
When to see a veterinarian
Many animals have scabs around their eyes, nose and on their limbs.
The wool falls out in patches and treatments against scabies or ringworm have not changed anything.
Lameness keeps coming back despite trimming and care.
Your rams have poor breeding results or reduced testicles.
Lambs do not grow and also have skin lesions.
The lesions reappear as soon as you stop the mineral supplement: talk to the veterinarian, a hereditary form is possible.
Prognosis
The response to supplementation is generally rapid and clear on the skin: it is even one of the elements which confirm the diagnosis.
The horn of the hooves and the fertility of rams require much more time: several months for the first, several weeks for the second.
Forms linked to a hereditary absorption defect recur each time complementation is stopped: these animals must not be kept for reproduction.
At the herd level, the prognosis is good as long as the ration is corrected taking into account the elements that block absorption.
Frequently asked questions
I have treated for scabies without result, what should I do?
It's a classic situation. Crusts around the eyes, nose, limbs and scrotum, with moderate itching and shedding of wool, point to a zinc deficiency rather than a parasite. The veterinarian will do a scraping to rule out scabies and will look at the ration.
My food contains zinc, is a deficiency still possible?
Yes, and it's common. Excess calcium, water rich in iron or certain fodder prevent the absorption of the zinc that is present. This is why we analyze the entire ration and the water, not just the zinc content.
My ram has poor breeding results, could zinc be the cause?
Yes, it is a known sign of zinc deficiency, sometimes the only visible one in a herd. An examination of the semen and an assessment of the ration are ideally carried out several weeks before the fight, because fertility takes time to return.
Can I buy zinc and donate it myself?
No. Excess zinc unbalances other trace elements, particularly copper, to which sheep are very sensitive. The correction is made on prescription, with a form and quantity adapted to your ration.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
ANSES — Agence nationale de sécurité sanitaire (France)
Content reviewed by the TunisieVet editorial team · Updated 09 September 2026
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