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Pregnancy toxemia in sheep
In the last month of gestation, lambs gain weight very quickly and take up almost all the available energy. At the same time, they occupy an increasing amount of space in the abdomen and leave less and less volume to the rumen: the ewe can...
What is it?
In the last month of gestation, lambs gain weight very quickly and take up almost all the available energy. At the same time, they occupy an increasing amount of space in the abdomen and leave less and less volume to the rumen: the ewe can no longer eat as much as she needs.
When the energy supply does not follow, the body draws on its fat reserves. This combustion produces ketone bodies which accumulate in the blood and gradually poison the animal.
It is the typical disease of sheep carrying two, three or more lambs. It is not contagious: it is a breeding disease, and therefore preventable. An affected ewe almost always signals a feeding problem that affects the entire flock.
Key point
Vital emergency. A ewe at the end of gestation which stops eating, appears blind or remains lying down must be seen without delay: a few hours change the prognosis, for her as for her lambs.
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:
The first signs are discreet and easy to miss in a flock: the ewe isolates itself, stays behind when the flock moves, no longer comes to the trough.
She first refuses concentrates, then fodder.
She seems absent: head lowered, ears drooping, gaze fixed. She reacts badly when we approach her and seems to no longer see; she bumps into obstacles or remains motionless in front of an open door.
Tremors, jaw movements, grinding of teeth, sometimes head leaning against a wall or tilted back.
The approach becomes hesitant, staggering. The sheep ends up lying down and never gets up again, despite still being conscious.
In the advanced stage: convulsions, coma, death within a few days if nothing is done.
A particular sweet smell of the breath is sometimes perceived by the breeder.
Many ewes abort or give birth to weak, non-viable lambs.
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 cause is a lack of energy in the ration at the time when the need explodes, that is to say during the last third of gestation.
The more lambs the ewe bears, the greater the gap between what she receives and what she consumes.
A sudden fast very often triggers illness in an already fair ewe: transport, change of batch, sorting, shearing, bad weather which prevents going out, failure of supply, food refused because it has changed.
Poor quality fodder, bulky and low in energy, maintains the problem even if the quantity distributed seems sufficient.
Sheep that are too thin have no reserves; sheep that are too fat eat less and mobilize their fat in a disorderly manner. Both extremes are at risk.
Pregnancy of two or more lambs, particularly in prolific ewes.
Body condition too thin or on the contrary too fat at the end of gestation.
Any deprivation of food, even short, in the last month: transport, handling, change of sheepfold, bad weather.
Sudden change of ration or food.
Insufficient space at the trough: dominated sheep eat little and are the first to be affected.
Old sheep, lame sheep that have difficulty moving to the trough, sheep with worn teeth.
Significant parasitism, which diverts energy and suppresses the appetite.
Insufficient or too cold drinking water: a sheep that drinks little eats little.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
You must call the veterinarian at the first signs: the later the intervention, the lower the chances.
The veterinarian examines the ewe, assesses its body condition, the state of pregnancy and the probable number of lambs, and looks for dehydration.
Simple analyzes of blood, milk or urine can highlight excess ketone bodies and confirm the diagnosis.
It rules out diseases which give a similar picture: hypocalcemia, listeriosis, nervous diseases, poisoning.
Above all, he examines the rest of the batch and the ration distributed. A sick ewe is a warning signal for the entire flock: others are often already affected without it being visible yet.
Treatment
Treatment is an emergency and is entirely the responsibility of the veterinarian.
The principle is to quickly provide the energy that is lacking, orally or by infusion depending on the condition of the ewe, to correct dehydration and the imbalances that accompany it.
The products, routes of administration and quantities are determined by the veterinarian for each animal. Recipes copied from one sheep to another or from one farm to another waste time and can make the situation worse.
When the ewe does not respond and the lambs are close to term, the veterinarian may decide to induce lambing or perform a cesarean section: as long as the lambs are there, they continue to drain the ewe of its energy.
Comfort care is just as important: put the ewe in a separate box, on clean bedding, sheltered, with lukewarm water and very good quality fodder within reach of the head, pick it up several times a day if it is lying down.
During this time, the ration of the entire flock should be reviewed with the veterinarian, without waiting for further cases.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
This is the most important part, because this disease is much better prevented than cured.
Gradually increase energy intake during the last third of gestation, at the precise moment when the need disappears and the ingestion capacity decreases. The end-of-gestation ration cannot be that of mid-gestation.
Split the concentrate meals rather than distributing everything at once, to protect the rumen and allow each ewe to eat.
Never leave a pregnant ewe fasting, even for a few hours: provide fodder before and after transport, sorting, shearing or changing buildings, and avoid these operations as much as possible at the end of gestation.
Any change in ration must be introduced gently, over several days.
Separate the batches according to the number of lambs carried when an ultrasound has been carried out: ewes with two or three lambs have needs that the others do not have.
Monitor body condition by regular palpation of the back, to identify ewes that are too thin or too fat before the end of gestation.
Provide enough space at the trough for everyone to eat at the same time, and leave clean water at all times.
Control parasitism and control teeth and feet: a sheep that cannot move or chew will not eat.
Possible complications
Death of lambs in the womb, abortion, giving birth to weak lambs that do not suckle.
Retained placenta and infection of the uterus after parturition.
Colostrum and milk production greatly reduced: surviving lambs get off to a bad start.
Associated hypocalcemia, common in the same ewe and which worsens the picture.
Liver damage, exhausted by the massive mobilization of fats.
Death of the sheep in advanced forms, despite treatment.
When to see a veterinarian
A ewe at the end of gestation isolates itself from the flock and no longer comes to eat.
She refuses concentrate or fodder while the others eat normally.
She appears dazed, seems to no longer see, bumps or remains frozen.
She trembles, grinds her teeth or staggers.
She is lying down and does not get up: call immediately, without waiting until the next day.
Several ewes from the same group appear sluggish or are eating less: have the ration reviewed without waiting for a serious case.
Prognosis
The prognosis depends almost entirely on the precocity of the intervention.
A sheep caught in the early stages, still standing and still able to eat, often recovers.
A lying sheep that never gets up again has a poor prognosis, even if it is well cared for.
Lambs are frequently lost, including when the mother escapes.
At the flock level, the real result comes down to feeding behavior: correcting the ration protects ewes that are not yet sick.
Frequently asked questions
Why are it always my best sheep who are affected?
Because they are the ones who carry the most lambs. The larger the litter, the higher the energy requirement at the end of gestation, and the greater the gap with what the ewe can eat. Prolificacy is not a defect: it simply requires a suitable diet during the last third of gestation.
Can I give sugar or molasses myself while waiting for the vet?
Do not take any treatment initiative. A dazed or lying ewe swallows poorly and risks passing liquid into its lungs. Call the veterinarian, put the ewe in a quiet, sheltered area, with water and good fodder within reach, and follow his instructions.
My sheep is fat: she can't lack energy, can she?
Yes. A sheep that is too fat eats less, its rumen is compressed by abdominal fat and by the lambs, and it mobilizes its reserves in a disorderly manner. Excess body condition is a risk factor in the same way as thinness.
I transported my pregnant sheep for half a day, should we be worried?
This is exactly the type of situation that triggers illness. Even a short fast at the end of gestation is enough. Provide fodder before and after transport, monitor appetite over the following days and report to the veterinarian any ewes that remain behind.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
AVMA — American Veterinary Medical Association
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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