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Diarrhea in lambs
Diarrhea in young lambs is the leading cause of mortality during the lambing period. It mainly affects animals in the first days and weeks of life. It is not a single disease but a syndrome: several different microbes cause the same picture...
What is it?
Diarrhea in young lambs is the leading cause of mortality during the lambing period. It mainly affects animals in the first days and weeks of life.
It is not a single disease but a syndrome: several different microbes cause the same picture. What kills the lamb is not the microbe itself, it is the loss of water and mineral salts caused by diarrhea.
A lamb is a very small reservoir of water: it dehydrates in a few hours, much faster than an adult. A lamb that has diarrhea in the morning may be lying down and unable to get up in the evening.
Key point
Dehydration can kill a newborn lamb in less than a day. Faced with a lamb that is no longer suckling, you must act the same day.
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:
Liquid or pasty, yellowish, whitish or greenish stools, often smelly, which soil the hindquarters and tail.
Lamb which no longer seeks the breast, or which suckles sluggishly then gives up.
Arched back, drooping ears, lamb which remains lying down and lets itself be caught without reacting.
Signs of dehydration: sunken eyes, dry and cold mouth, skin that remains wrinkled when pinched.
Lamb cold to the touch, which no longer stands up, then which no longer raises its head: this is a serious stage.
In some forms, blood or red filaments in the stools, and visible abdominal pain (the lamb complains, lies down and gets up again and again).
On the survivors, the belly remains swollen, the hair bristles and growth never completely catches up.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Several agents may be involved, alone or in combination, and they cannot be distinguished with the naked eye.
Bacteria, firstly certain strains of colibacillus (Escherichia coli), very common in the very first days of life; salmonella gives more severe forms, with blood.
Viruses, particularly rotaviruses, which damage the lining of the intestine.
Microscopic parasites: cryptosporidia, common in sheepfolds, and a little later coccidia (see the coccidiosis sheet, which concerns already older lambs).
In all cases, the starting point is the same: the lamb swallows the microbes present in dirty bedding, on its mother's soiled teats or on the farmer's hands and boots, while its defenses are still weak.
A lamb which has not received enough colostrum, or which has received it too late, is without protection: this is the factor which weighs the most.
Insufficient colostrum, of poor quality, or taken too late after birth.
Overcrowded sheepfold, damp litter, lambing pens reused without being re-mulched or cleaned.
Group lambings: microbial pressure rises regularly from the start to the end of the season, and the last born are the most exposed.
Lambs from multiple litters, low birth weight lambs, lambs born to a primiparous or poorly nourished ewe at the end of gestation.
Ewe with dirty udders, teats soiled with mud or dung.
Cold and humidity, which weaken the lamb and cause it to remain lying on contaminated bedding.
Adoption or artificial breastfeeding poorly managed, drinking equipment poorly cleaned.
Transmission
The microbes come out with the stools of sick lambs and of some carrier ewes without being sick.
They contaminate bedding, lambing pens, buckets, teats, hands and boots.
The lamb becomes contaminated by suckling a soiled udder or by licking the litter and walls.
Sick lambs excrete enormous quantities of microbes: a single non-isolated case is enough to start a series throughout the entire sheepfold.
Contamination is also transmitted from one year to the next when premises are not emptied and disinfected between two lambing seasons.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
We must have the first cases examined rather than waiting: this is the only way to know what we are dealing with and to act on the whole lot.
The veterinarian assesses the degree of dehydration, the lamb's temperature, its ability to stand and suckle. These three elements decide what action to take in an emergency.
He often asks for a stool analysis on several untreated sick lambs: this is what makes it possible to identify bacteria, viruses or parasites, because the treatment is not the same.
The autopsy of a dead lamb, when possible quickly, provides a lot of information and avoids treating the entire flock blindly.
The veterinarian will rule out other causes of lamb death that may resemble this, particularly enterotoxemia and, in older lambs, coccidiosis.
While waiting for its arrival: isolate the sick lamb in a dry and warm place with its mother, do not leave it on cold and damp litter, and wash your hands before handling the other lambs.
Treatment
The top priority is to rehydrate. A lamb dies from the loss of water and salts, not from the diarrhea itself. The veterinarian indicates the route to use depending on the condition of the animal: through the mouth if it is still suckling and standing, by perfusion if it is collapsed.
Veterinary rehydration solutions provide water, salts and sugar in the right proportions; water alone is not enough and milk alone does not rehydrate.
The lamb should not be deprived of milk: letting it suckle from its mother between doses of the solution is still recommended, unless otherwise indicated by the veterinarian.
Reheating the lamb is inseparable from the rest: a cold lamb no longer digests and does not benefit from what we give it.
An antibiotic is only useful in certain bacterial forms, and it is the veterinarian who decides whether it is justified: it is useless against viruses and against cryptosporidia. Treatments given randomly maintain resistance and delay the true diagnosis.
Against certain parasites, specific treatments exist and are prescribed. No dose, no product should be taken from one year to the next or from a neighbor without veterinary advice.
Separate the sick from the healthy and tend to the healthy lambs first, sick last, so as not to carry germs onto your hands.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Colostrum is the first pillar. The lamb should nurse as soon as possible after birth, and the veterinarian will advise what to do for weak lambs or multiple litters. The more time passes, the less the intestine allows antibodies to pass through.
Disinfection of the navel at birth closes the widest entry point for microbes.
A clean and dry sheepfold is the third pillar: abundant and renewed mulch, lambing pens cleaned between two ewes, water points and feeders out of reach of dirt.
Avoid overloading: the more animals there are per square meter, the higher the microbial pressure.
Take care of the diet of ewes at the end of gestation: this is what determines the quality of the colostrum and the vigor of the lamb.
Clip or clean the hindquarters and udders of ewes before lambing.
Clean and disinfect drinking equipment after each use; never make sick and healthy lambs drink from the same bucket.
Empty, clean and disinfect the sheepfold between two lambing seasons, and leave to dry.
Separate newborn lambs from older lambs, which shed germs without being sick.
Vaccination
Vaccines intended for sheep at the end of gestation exist against certain agents of neonatal diarrhea: the sheep produces antibodies which it transmits in its colostrum.
Their availability and their interest vary according to the regions and according to the microbes actually present in the breeding: it is up to the veterinarian to say if they are justified in you, and at what time of the gestation to do them.
A maternal vaccination only protects if the lamb actually drinks its colostrum: vaccination never replaces taking colostrum or keeping the sheepfold clean.
Possible complications
Severe dehydration and death within a few hours in youngest lambs.
Passage of microbes into the blood, with damage to the joints (polyarthritis) or the meninges.
Long-term growth retardation among survivors, which penalizes the entire lot at sale.
Superinfection by other agents on an already damaged intestine.
At the herd level, lasting contamination of premises which causes the problem to return the following year.
When to see a veterinarian
A lamb has diarrhea and is no longer suckling: it's already an emergency, don't wait until the next day.
Her skin remains wrinkled when you pinch her, her eyes are sunken, her mouth is cold.
He is lying down, does not get up or no longer raises his head.
There is blood in the stools.
Several lambs are affected in a few days, or one lamb has died suddenly: have the batch examined without delay.
The diarrhea continues despite the rehydration you have given.
Transmission to humans
Some agents of lamb diarrhea are transmitted to humans, particularly cryptosporidia and salmonella. Contamination occurs through hands brought to the mouth after contact with a sick lamb or its litter.
Children, pregnant women, the elderly and people with weakened defenses are most at risk and should avoid handling sick lambs.
Wash your hands thoroughly with soap and water after each contact, before eating and smoking. Keep clothing and boots reserved for the sheepfold, and do not eat in the building.
If you experience persistent diarrhea after caring for lambs, tell your doctor that you are working with sheep.
Prognosis
Lamb taken early, rehydrated and reheated most often heals well.
A lamb already lying down, cold and unable to get up has a guarded prognosis, even when well cared for.
At the herd level, the outcome depends less on the treatment than on what is done to the colostrum, navel and litter: farms that meet these three points see the series of diarrhea disappear.
Frequently asked questions
Should we stop milk when a lamb has diarrhea?
No. Depriving a lamb of milk weakens it and slows its healing. You must let him suckle from his mother and also provide him with a veterinary rehydration solution, unless otherwise instructed by your veterinarian.
Is homemade sweet and salt water enough?
No. The proportions of water, salts and sugar must be precise for the intestine to absorb the liquid. An incorrectly dosed home preparation can worsen dehydration. Veterinary solutions are designed for this.
Why are the last lambs born the most affected?
Because the amount of microbes present in the sheepfold increases throughout the lambing season. Mulching abundantly, cleaning the pens between two ewes and separating the ages slows down this rise.
Would an antibiotic given to all lambs prevent diarrhea?
No, and that's a bad idea. Most diarrhea is not due to sensitive bacteria, the antibiotic given indiscriminately creates resistance and masks the real problem, which is almost always colostrum or cleanliness.
Can I catch something while caring for my lambs?
Yes, some agents like cryptosporidia pass to humans. Wash your hands after each contact and keep children away from sick lambs.
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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