Salmonellosis in Sheep
- See your vet immediately if a sheep has severe diarrhea, fever, weakness, dehydration, collapse, or sudden abortion.
- Salmonellosis is a bacterial infection that can affect the intestines, bloodstream, and in pregnant ewes, the uterus and placenta.
- Common signs include foul or watery diarrhea, depression, fever, poor appetite, dehydration, and sometimes abortion or sudden death.
- Diagnosis usually needs fecal, blood, or tissue testing because other sheep diseases can look similar.
- This disease is zoonotic, so careful hygiene, isolation, and manure handling matter for both flock health and human safety.
What Is Salmonellosis in Sheep?
Salmonellosis is an infection caused by Salmonella bacteria. In sheep, it most often affects the intestinal tract, but it can also spread into the bloodstream and cause septicemia, which is a life-threatening whole-body infection. In pregnant ewes, some Salmonella strains can also trigger abortion, stillbirths, or weak lambs.
This disease can show up as a single sick sheep or as a flock problem, especially when animals are stressed, crowded, transported, or exposed to contaminated feed, water, bedding, or manure. Merck Veterinary Manual notes that salmonellosis is more common in sheep when they are intensively grouped or stressed, and that abortion is a hallmark sign with some sheep-adapted strains.
Salmonellosis also matters because it is zoonotic. That means people can get infected from sick sheep, manure, contaminated lambing areas, or contaminated food and water. If you are caring for a sick sheep, use gloves, dedicated boots, and careful handwashing, and involve your vet early.
Symptoms of Salmonellosis in Sheep
- Watery or foul-smelling diarrhea
- Fever
- Depression or marked lethargy
- Poor appetite or not eating
- Dehydration, sunken eyes, dry gums, weakness
- Rapid decline, collapse, or signs of septicemia
- Abortion in pregnant ewes, often after fever and illness
- Sudden death, especially in severe systemic cases
Some sheep develop mainly intestinal signs, while others become systemically ill very quickly. Pregnant ewes may show fever, depression, and poor appetite before aborting. Merck also notes that there may be no specific placental lesions, so abortion cases still need testing.
See your vet immediately if a sheep is weak, dehydrated, unable to stand, has bloody or profuse diarrhea, or if any pregnant ewe aborts. Fast treatment can improve the chances of survival and may help limit spread through the flock.
What Causes Salmonellosis in Sheep?
Salmonellosis happens when sheep ingest Salmonella bacteria from contaminated manure, feed, water, bedding, equipment, or the environment. Rodents and other animals can help spread the organism on farms, and contaminated feed is a recognized source. Carrier animals may also shed bacteria without looking obviously sick.
Different Salmonella types behave differently. Merck Veterinary Manual notes that S Abortusovis is associated with reproductive disease in sheep, while other serotypes such as S Dublin, S Typhimurium, and S Arizona have also caused abortions in sheep. In the United States, Merck reports that S Abortusovis has not been reported, while other serotypes occur worldwide.
Stress often plays a major role. Shipping, crowding, lambing pressure, poor sanitation, abrupt diet changes, concurrent disease, and heavy environmental contamination can all increase risk. Young, old, pregnant, or immunologically stressed sheep may be more likely to become seriously ill after exposure.
How Is Salmonellosis in Sheep Diagnosed?
Your vet will start with the history, flock pattern, physical exam, and the sheep's hydration and pregnancy status. Because diarrhea and abortion in sheep have many possible causes, diagnosis should not rely on signs alone. Merck Veterinary Manual states that salmonellosis is diagnosed by repeated isolation from feces when carrier status is suspected, or by a single isolation from feces, blood, or tissue when the animal also has compatible clinical signs.
Testing may include fecal culture or PCR, bloodwork to assess dehydration and systemic illness, and in abortion cases, culture or PCR on the placenta, fetus, or uterine discharge. Your vet may also recommend necropsy and lab submission if a sheep dies, because that can be the fastest way to confirm the cause and guide flock-level decisions.
Common differentials include coccidiosis, enterotoxemia, parasitism, listeriosis, campylobacteriosis, and other causes of abortion. A one-time positive fecal result in a sheep without signs may not be enough to confirm active disease, so your vet may advise repeat sampling or broader flock testing.
Treatment Options for Salmonellosis in Sheep
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm call or on-farm exam
- Isolation from the flock
- Temperature check and hydration assessment
- Oral fluids and electrolytes if the sheep is still standing and swallowing well
- NSAID or other supportive medications if your vet feels they are appropriate
- Targeted fecal or abortion sample submission when possible
- Strict manure, bedding, and lambing-area hygiene
Recommended Standard Treatment
- Full veterinary exam and flock risk assessment
- Fecal culture or PCR, and abortion testing when relevant
- CBC and chemistry or packed cell volume/total solids when available
- IV or subcutaneous fluids depending on severity
- Parenteral antimicrobials when your vet suspects septicemic disease or based on likely resistance patterns and food-animal regulations
- NSAIDs and endotoxemia support as indicated
- Recheck plan, isolation, and biosecurity guidance for the rest of the flock
Advanced / Critical Care
- Hospitalization or intensive on-farm critical care
- Repeated IV fluid therapy and electrolyte correction
- Serial bloodwork and close monitoring for septicemia or shock
- Blood culture or additional diagnostics in severe cases
- Aggressive treatment for endotoxemia, pain, and recumbency care
- Necropsy and flock-level outbreak planning if deaths occur
- Expanded biosecurity and environmental management recommendations
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Salmonellosis in Sheep
Bring these questions to your vet appointment to get the most out of your visit.
- Does this sheep need immediate fluids, and can that be done on-farm or is hospitalization more appropriate?
- Which samples should we submit right now: feces, blood, placenta, fetus, or uterine discharge?
- Based on this sheep's signs, do you suspect intestinal salmonellosis, septicemia, or abortion-related infection?
- Are antimicrobials appropriate in this case, and what are the food-animal withdrawal considerations?
- How should I isolate this sheep and handle manure, bedding, and lambing materials safely?
- Should we test or monitor other flock members, especially lambs or pregnant ewes?
- What signs mean this sheep is getting worse and needs emergency recheck today?
- What changes to feed, water, sanitation, and stocking density could reduce the risk of more cases?
How to Prevent Salmonellosis in Sheep
Prevention focuses on biosecurity, sanitation, and stress reduction. Keep feed and water clean, store feed to limit contamination by rodents and wildlife, remove manure promptly, and clean lambing areas between animals when possible. APHIS sheep and goat biosecurity guidance supports using a written biosecurity plan and separating sick animals quickly.
Isolate any sheep with diarrhea, fever, or abortion until your vet advises otherwise. Handle aborted fetuses, placentas, and contaminated bedding as potentially infectious. Wear gloves, wash hands well, and keep children, older adults, pregnant people, and anyone with a weakened immune system away from sick animals and contaminated areas.
Work with your vet on flock-level prevention. That may include reviewing stocking density, transport stress, nutrition, water access, quarantine for new arrivals, and rodent control. If one sheep tests positive, your vet may recommend additional sampling or management changes because some animals can continue shedding Salmonella after they look clinically improved.