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Hypocalcemia in sheep
Calcium makes muscles work, including those of the rumen and heart. At the end of gestation and then at the beginning of lactation, the lambs and the udder consume a lot at once. If the body cannot mobilize calcium from the bones and food q...
What is it?
Calcium makes muscles work, including those of the rumen and heart. At the end of gestation and then at the beginning of lactation, the lambs and the udder consume a lot at once.
If the body cannot mobilize calcium from the bones and food quickly enough, the blood level drops: the muscles no longer respond, the ewe staggers then lies down.
Unlike cows, sheep often fall before giving birth rather than after. Stress or sudden fasting, particularly transportation, frequently triggers it: hence the name transportation tetany.
Key point
Vital emergency. A lying sheep that does not get up must be seen the same day. Never inject calcium yourself: if administered incorrectly, it can kill the animal in a few minutes.
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:
At first, the ewe stays behind the pack, walks stiffly, seems unsteady on its feet.
Muscle tremors, especially in the shoulders and sides.
She stops eating and ruminating; the left side bloats because the rumen stops.
The droppings become rare, hard, then absent.
She lies down, first on the sternum, with her head often turned to her side, then to the side.
The ears and extremities are cold, breathing becomes rapid and shallow.
Body temperature is not elevated, despite the misleading name milk fever.
Without treatment, the condition worsens within a few hours to the point of coma.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The calcium needs of lambs at the end of gestation, then during the production of colostrum and milk, suddenly exceed what the body can mobilize.
A cessation of feeding cuts off the daily intake: transport, sorting, shearing, change of sheepfold, bad weather, refused ration.
A ration too rich in calcium during the end of gestation accustoms the body to ease: at the peak of need, it no longer knows how to draw effectively from the bone. This effect is well established and explains why mineral supplementation at the end of gestation must be discussed with the veterinarian.
Certain plants rich in oxalates fix calcium in the diet and make it unavailable.
An unusual effort or a long walk just before giving birth can be enough to tip an already fair ewe over the edge.
Last weeks of gestation and first days after giving birth.
Ewe carrying several lambs and strong milking ewes.
Older ewes, which mobilize their bone calcium less well.
Transport, handling, change of lot or building at the end of gestation.
Fasting, even short, and sudden change of ration.
Mineral supplementation poorly suited to the end of gestation.
Special pastures or forages rich in oxalates.
Overwork: long walk, dog, heat.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The call to the veterinarian must be immediate: the diagnosis and treatment are carried out at the same time.
The veterinarian examines the ewe, takes its temperature, listens to the heart and rumen, and assesses the gestation stage.
It distinguishes hypocalcemia from related conditions, in particular pregnancy toxemia, which affects the same ewes at the same time and can coexist with it, but also listeriosis, tetanus, poisoning or blocked birth.
A blood test confirms the fall in calcium when a laboratory is accessible, but it is not expected to treat.
The rapid response to calcium treatment is in itself a diagnostic element.
Treatment
Treatment involves restoring blood calcium. It is administered by the veterinarian, by a route and at a pace that he chooses according to the condition of the ewe.
This gesture is not trivial: administered too quickly or by the wrong route, calcium can stop the heart. This is why it must never be practiced by the breeder on the basis of a neighborhood council.
The veterinarian monitors the heart during administration and adjusts according to response.
When the diagnosis is good and treatment is early, the ewe often gets up in less than an hour, belches, urinates and starts eating again.
A relapse in the following days is possible: the ewe must be kept under close supervision, in a quiet area, with water and fodder available.
If the ewe does not respond as expected, the veterinarian re-examines the diagnosis: associated gestational toxemia is common.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Avoid any fasting at the end of gestation and at the beginning of lactation: this is the most effective measure.
Limit transport, sorting and handling in the final weeks; when they are essential, provide fodder before and after, and avoid long journeys on foot.
Discuss mineral supplementation at the end of gestation with the veterinarian rather than adding calcium as a matter of principle: excess at the end of gestation is counterproductive.
Introduce any ration changes gradually.
Ensure permanent access to clean water and sufficient space at the trough.
Particularly monitor older ewes and those carrying several lambs.
Be vigilant on plots known for their plants rich in oxalates.
Possible complications
Death within a few hours if the sheep is not treated.
Rumen bloating which may interfere with breathing in a ewe lying on its side.
False swallowing and pneumonia if you try to make a sheep that no longer swallows drink.
Difficult delivery, ineffective contractions, retained placenta.
Associated gestational toxemia, which clearly darkens the prognosis.
Muscle and nerve damage in a ewe lying down for a long time.
When to see a veterinarian
A ewe at the end of gestation or recently lambed walks stiffly, trembles or staggers.
She no longer eats, no longer ruminates and her left side is swelling.
She is lying with her head turned to her side and does not get up: call immediately.
Signs appear when returning from transport or batch change.
The ewe got up after treatment and then fell back: call the vet again, a relapse can be treated.
Prognosis
Excellent when treatment is administered early: many sheep recover within an hour and return to normal life.
The prognosis becomes poorer if the ewe has been lying down for a long time, if it is dehydrated or if gestational toxemia is associated.
Relapses are possible and do not mean that the treatment was bad.
Frequently asked questions
What is the difference with gestational toxemia?
Both affect the same sheep at the same time and look very similar. Hypocalcemia sets in within a few hours and responds very quickly to calcium treatment; toxemia sets in over several days, with an animal that appears absent, and responds slowly. The two can co-exist, which is all the more reason to bring in the vet rather than guessing.
Why do we talk about milk fever when the ewe is cold?
The name is old and misleading. There is no fever: the temperature is normal or low, and the ears are cold. A thermometer is also useful to distinguish this disease from an infection.
Should we give calcium for prevention to all sheep?
No, and it is even counterproductive at the end of gestation: too much calcium at this time prevents the body from learning to mobilize its bone reserves. Mineral supplementation must be discussed with the veterinarian depending on the ration and fodder.
My ewe had hypocalcemia: will she start again?
The risk of relapse exists in the days that follow, and a ewe having had an episode is more exposed in subsequent years. Report it and pay particular attention to its diet around giving birth.
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 August 2026
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