Pig Fever: Signs, Common Causes & When to Seek Veterinary Care

Fever is a symptom, not a diagnosis. In pigs, it most often points to infection or inflammation. Respiratory disease is a common reason, including pneumonia and swine influenza. These pigs may also cough, breathe faster, seem tired, or stop eating. Bacterial infections such as swine erysipelas and Streptococcus suis can also start with fever and may progress to lameness, skin changes, neurologic signs, or severe illness.

Digestive disease can also cause fever. A pig with fever plus diarrhea may have an intestinal infection such as salmonellosis or another enteric disease. Skin wounds, abscesses, urinary tract problems, uterine infection in an intact female, or infected joints can also raise body temperature. In some pigs, fever follows vaccination for a short time, but that should be mild and brief.

Not every hot pig has a true fever. Pigs are very sensitive to overheating because they do not sweat effectively. Heat stress or heat stroke can cause a dangerously high temperature, weakness, open-mouth breathing, and collapse. This is an emergency and can look similar to infectious fever at first.

A final concern is that some serious swine diseases, including African swine fever and classical swine fever, can cause fever and sudden illness. These diseases are reportable and require veterinary and animal health involvement. Pet parents should not try to sort that out alone. If your pig has fever with severe depression, skin discoloration, bleeding, or rapid decline, contact your vet right away.

See your vet immediately if your pig has a fever and is also breathing hard, refusing food or water, unable to stand, vomiting, having severe diarrhea, showing tremors or seizures, acting confused, or developing red, purple, or bruised-looking skin. The same is true for pigs that are very young, elderly, pregnant, or have other medical problems. A temperature that stays elevated, or any pig that seems to be getting worse over hours instead of better, needs urgent care.

Same-day veterinary care is also wise if the fever is paired with coughing, nasal discharge, lameness, swollen joints, a painful belly, straining to urinate, or a foul smell from the mouth, skin, or rear end. Pigs often hide illness until they are quite sick. A pig that is quieter than usual, isolates, or stops rooting and eating may be telling you more than the thermometer does.

Home monitoring may be reasonable only for a bright, hydrated pig with a very mild temperature increase and no other concerning signs, such as a pig that had a vaccine recently and is still eating and acting normally. Even then, call your vet for guidance, because pigs can worsen quickly and temperature readings can be tricky.

If you are monitoring at home while waiting for an appointment, keep your pig in a calm, shaded, well-ventilated area with easy access to fresh water. Do not force exercise, do not bundle your pig in blankets, and do not give over-the-counter human medications unless your vet specifically tells you to.

Your vet will start with a physical exam and confirm whether your pig truly has a fever or is overheated. They will check temperature, breathing effort, heart rate, hydration, gum color, skin, joints, and belly comfort. History matters too. Your vet may ask about recent travel, contact with other pigs, diet changes, wounds, coughing, diarrhea, vaccination history, and whether any pork products or table scraps were fed.

Testing depends on the signs. Common first steps include bloodwork, fecal testing, and sometimes nasal or throat samples if respiratory disease is suspected. If your pig is coughing or breathing hard, your vet may recommend chest imaging. If there is lameness, swelling, or a wound, they may sample fluid or look for an abscess. In intact females, reproductive tract disease may also be considered.

Treatment is based on the cause and how sick your pig is. Options may include fluids, anti-inflammatory medication chosen by your vet, antibiotics when a bacterial infection is likely, oxygen support, cooling measures for heat-related illness, and hospitalization for pigs that are weak or dehydrated. If your vet suspects a reportable swine disease, they may involve state or federal animal health officials for testing and guidance.

Because fever can be a sign of contagious disease, your vet may also recommend isolation from other pigs, careful cleaning of boots and equipment, and limiting visitors or animal movement until the cause is clearer.

Home care should support your pig while you are in contact with your vet, not replace veterinary care for a true fever. Keep your pig in a quiet, clean area away from other pigs until your vet says it is safe. Offer fresh water at all times. If your pig is willing to eat, offer its usual balanced pig diet rather than rich treats or sudden diet changes. Watch for urine and stool output, because dehydration can develop quickly.

If your pig seems overheated, move it to a cool, shaded, well-ventilated space. Tepid water on the skin and a fan can help with cooling. Avoid ice baths or very cold water unless your vet directs otherwise, because overly aggressive cooling can create other problems. If your pig is shivering, weak, or mentally dull, stop and call your vet right away.

Take notes for your vet. Record the temperature, time of day, appetite, water intake, breathing changes, coughing, diarrhea, vomiting, lameness, and any skin color changes. Photos or short videos can be very helpful, especially if the signs come and go.

Do not give acetaminophen, ibuprofen, aspirin, or leftover antibiotics unless your vet specifically prescribes them for your pig. These can be harmful, can hide worsening disease, and can delay the right diagnosis. If your pig is not improving, or if any new red-flag sign appears, seek veterinary care immediately.