Sheep Fever: How to Tell, Common Causes & When to Call a Vet

Fever is a sign, not a diagnosis. In sheep, a normal rectal temperature is roughly 100.9-103.8°F (38.3-39.9°C), so a true fever usually means the body is reacting to infection or inflammation. Brief temperature bumps can happen after transport, chasing, crowding, or hot weather, which is why the full picture matters: appetite, breathing, manure, gait, udder, and behavior.

Common infectious causes include pneumonia, especially after stress, weather swings, or poor ventilation. Sheep with respiratory disease may also cough, breathe faster, stand apart from the flock, or have nasal discharge. Listeriosis is another important cause, especially if poor-quality silage is involved. These sheep may start with fever and depression, then develop circling, facial droop, drooling, or trouble standing.

Fever can also come from digestive and reproductive disease. Salmonellosis may cause high fever, depression, and later diarrhea. In ewes, fever after lambing or abortion raises concern for metritis, retained placenta, or septic complications. Mastitis can cause a hot, painful udder, reduced milk, and a sick-looking ewe. In some regions, tick-borne disease can also cause sudden fever, poor appetite, and a drop in milk production.

Do not overlook painful inflammatory problems such as severe foot infections, abscesses, wound infections, or joint infections. A sheep with fever and lameness may have more than a hoof trim problem. Because several causes are contagious or zoonotic, early veterinary guidance helps protect both the flock and the people caring for them.

See your vet immediately if your sheep has a fever plus any major red flag: hard or open-mouth breathing, blue or very pale gums, collapse, inability to rise, seizures, circling, head tilt, severe weakness, repeated straining, a swollen painful udder, foul-smelling discharge after lambing, or recent abortion. The same is true for lambs, because young animals can decline fast.

A same-day call is wise if the temperature stays elevated after the sheep has rested in a cool, quiet area for 20-30 minutes, or if the sheep is off feed, isolating from the flock, coughing, lame, dehydrated, or acting dull. Fever with diarrhea, nasal discharge, or neurologic signs should not wait. If more than one sheep is affected, contact your vet sooner rather than later because flock disease can spread quickly.

You may be able to monitor briefly at home if the temperature is only mildly elevated, the sheep is still bright, eating, drinking, walking normally, and there are no other concerning signs. Even then, recheck the temperature, watch manure and urine output, and keep notes on appetite and behavior. If the fever persists, rises, or new symptoms appear, call your vet.

Avoid guessing with leftover antibiotics or pain medications. In sheep, the right plan depends on age, pregnancy status, lactation, likely cause, and food-animal drug rules. Your vet can help you choose a practical option that fits the situation.

Your vet will usually start with a hands-on exam and flock history. That often includes confirming the temperature, checking hydration, listening to the lungs, examining the mouth and eyes, feeling lymph nodes, checking the feet, and in ewes, evaluating the udder and reproductive tract if needed. They may ask about recent lambing, abortion, transport, weather stress, feed changes, silage quality, parasite control, and whether other sheep are sick.

Testing depends on what your vet finds. Common next steps may include a CBC or chemistry panel, fecal testing, nasal or other culture samples, milk testing in a ewe with udder changes, or bloodwork to look for inflammation and organ involvement. If pneumonia is suspected, your vet may base treatment on the exam or add ultrasound or other diagnostics when available. If neurologic disease is present, listeriosis and other brain or ear problems move higher on the list.

Treatment is aimed at the cause and the sheep's stability. Your vet may recommend fluids, anti-inflammatory medication, antibiotics when bacterial infection is likely, nursing support, and isolation from the flock if contagious disease is possible. In reproductive cases, they may address retained placenta, metritis, mastitis, or complications after abortion. In severe cases, hospitalization or repeated farm visits may be the safest path.

Because sheep are food animals, your vet will also guide you on legal medication use and any meat or milk withdrawal times. That step is essential for flock health, food safety, and avoiding treatment mistakes.

Home care should support your vet's plan, not replace it. Move the sheep to a clean, dry, well-bedded pen with shade, easy access to water, and minimal stress. Separate from the flock if contagious disease is possible, but keep visual contact when practical because isolation can add stress. Recheck temperature only when the sheep has been calm for a bit, since chasing can falsely raise it.

Watch the basics closely: appetite, water intake, manure, urine, breathing rate, stance, and alertness. In a ewe, check the udder for heat, pain, asymmetry, or abnormal milk. After lambing or abortion, watch for foul discharge, straining, weakness, or failure to mother lambs. If your sheep is not drinking well, seems dehydrated, or is getting weaker, update your vet promptly.

Keep bedding and feed areas clean, and remove contaminated birthing material or manure as directed. Wash hands after handling sick sheep, especially if diarrhea, abortion, or udder infection is involved. Some causes of fever in sheep can also affect people.

Do not start over-the-counter or leftover medications on your own. Sheep need species-appropriate dosing, and food-animal withdrawal rules matter. If your sheep becomes down, neurologic, or short of breath, or if the fever climbs or lasts more than a day despite rest and care, see your vet immediately.