Pig Diarrhea and Enteritis: Causes, Symptoms, and When to Call a Vet

Pig diarrhea is a symptom, not a single disease. It describes stool that is looser, wetter, or more frequent than normal. Enteritis means inflammation of the intestines. When the intestinal lining is irritated or damaged, pigs may lose fluid into the gut, absorb nutrients poorly, and pass soft to watery stool.

This problem can range from mild and short-lived to life-threatening. In piglets, diarrhea can become dangerous very fast because they have less fluid reserve and can dehydrate within hours. In older pigs, ongoing diarrhea may lead to dehydration, weight loss, weakness, skin irritation around the rear end, and sometimes secondary problems such as rectal prolapse.

Several different diseases can look similar at home. Merck Veterinary Manual notes that common causes of diarrhea in pigs include enterotoxigenic E. coli, rotavirus, coccidiosis, clostridial disease, Salmonella, and porcine enteric coronaviruses such as transmissible gastroenteritis, porcine epidemic diarrhea, and porcine deltacoronavirus. Because treatment depends on the cause, your vet may recommend testing rather than guessing.

For pet pigs, diarrhea can also follow management issues like abrupt feed changes, contaminated water, access to garbage, overcrowding, or poor sanitation. Even when the cause seems minor, it is worth monitoring closely because pigs can hide illness until they are quite sick.

There are many possible causes, and age often gives useful clues. In nursing and recently weaned pigs, Merck Veterinary Manual lists enterotoxigenic E. coli, rotavirus, coccidiosis, Clostridium difficile, and Clostridium perfringens among important causes of diarrhea. Porcine enteric coronaviruses, including TGEV, PEDV, and PDCV, can also cause severe intestinal disease and spread quickly through feces and contact.

In older pigs and pet miniature pigs, diarrhea may also be linked to Salmonella, parasites, contaminated environments, stress, overcrowding, abrupt weaning, or sudden feed changes. Merck notes that coccidiosis is picked up from contaminated surroundings, and rotavirus can persist in facilities and spread by direct contact. Access to spoiled food, garbage, or unsafe treats can also upset the gut and introduce infection.

Not every case is infectious. Diet intolerance, overeating rich foods, poor-quality feed, mold, toxins, or medications can irritate the intestines. Some pigs with diarrhea are mainly dealing with inflammation and fluid loss, while others have deeper intestinal damage that affects nutrient absorption and raises the risk of dehydration and acidosis.

Because several causes overlap, it is safest not to assume all diarrhea is "just a stomach bug." Your vet will look at your pig's age, environment, diet history, exposure risks, and how quickly the signs started to narrow the list.

Diagnosis starts with a hands-on exam and a careful history. Your vet will ask about your pig's age, diet, recent feed changes, access to garbage or toxins, vaccination and parasite history, whether other pigs are affected, and how the stool looks. They will also check hydration, body temperature, belly comfort, gum moisture, and overall attitude.

Testing often begins with a fecal exam to look for parasites or coccidia. Depending on the case, your vet may also recommend fecal culture, PCR testing for infectious organisms, or bloodwork to assess dehydration, electrolyte changes, and organ function. Merck notes that diagnosis for conditions such as enteric colibacillosis, rotaviral enteritis, coccidiosis, and porcine coronaviral enteritis may involve organism detection in feces or intestinal samples, along with age pattern and herd history.

In more serious cases, your vet may suggest imaging, repeated blood tests, or hospitalization for monitoring. This is especially important if your pig is very young, weak, bloated, or passing blood. Severe diarrhea can look similar across different diseases, so testing helps your vet choose the most appropriate treatment options and infection-control steps.

If your pig dies unexpectedly or several pigs are sick, your vet may recommend necropsy or diagnostic lab submission. That can sound overwhelming, but it is often the fastest way to identify a contagious cause and protect the rest of the group.

Prevention starts with clean housing, clean water, and steady feeding routines. Many infectious causes spread through feces, contaminated surfaces, and close contact. Merck Veterinary Manual emphasizes environmental contamination and direct contact in diseases such as coccidiosis, rotaviral enteritis, and porcine coronaviral enteritis. Good sanitation, prompt manure removal, dry bedding, and avoiding overcrowding all help lower risk.

Feed management matters too. Avoid sudden diet changes, spoiled feed, moldy food, and access to trash or rich table scraps. Introduce new foods gradually, and ask your vet before making major diet changes for a pet pig. Stress from weaning, transport, mixing pigs, or poor temperature control can also make intestinal disease more likely.

Quarantine new pigs before introducing them to others, and keep sick pigs separated until your vet says it is safe. Wash hands well after handling pigs with diarrhea, especially before eating, because some infections such as Salmonella can affect people. Clean boots, bowls, and tools that contact feces.

Routine veterinary care is part of prevention. Your vet can help with parasite control, vaccination planning where appropriate, and a realistic biosecurity plan for your home or small herd. If your pig has repeated diarrhea episodes, ask your vet to review diet, housing, and fecal testing rather than treating each flare-up as a one-time event.