Diarrhea in Donkeys: Common Causes and When to Call a Vet

Diarrhea means manure that is looser, wetter, or more frequent than normal. In donkeys, it may show up as soft piles, cow-pat consistency manure, liquid feces, or staining down the hind legs and tail. A single mild episode can happen after a feed upset, but ongoing or profuse diarrhea can quickly become serious.

Most of the time, diarrhea is a sign that the large intestine is irritated or inflamed. That irritation may come from infection, parasites, toxins, medication effects, stress, or sudden changes in forage or concentrate intake. In equids, severe diarrhea is often discussed under the broader term colitis, which means inflammation of the colon.

Donkeys deserve extra caution because they often hide illness until they are quite sick. They are also prone to hyperlipemia when they stop eating, so a donkey with diarrhea and poor appetite should not be watched casually at home. Early support from your vet can help prevent dehydration, electrolyte problems, and more dangerous complications.

Many causes of diarrhea in donkeys overlap with those seen in horses, but donkey-specific management and metabolic risks matter. Common noninfectious causes include sudden feed changes, access to lush pasture, spoiled feed, sand ingestion, stress, transport, poor dentition, and medication reactions. Antibiotics can disrupt normal gut flora, and NSAID use can contribute to right dorsal colitis in equids. Parasites, especially small strongyles, are another important cause of diarrhea and weight loss.

Infectious causes can include Salmonella, Clostridioides difficile, Clostridium perfringens, equine coronavirus, and Neorickettsia risticii causing Potomac horse fever in endemic areas. In younger equids, rotavirus and Lawsonia may also be considered depending on age and history. Even when diarrhea is severe, a single exact cause is not always identified, so your vet may focus on stabilizing the donkey while testing is underway.

Some donkeys develop diarrhea as part of a broader illness rather than a primary gut problem. Liver disease, toxin exposure, systemic infection, and severe inflammatory disease can all affect manure quality. Because donkeys can become dangerously ill when they go off feed, a case that starts as mild diarrhea can become more urgent if appetite drops, dehydration develops, or the donkey becomes quiet and withdrawn.

Diagnosis starts with a careful history and physical exam. Your vet will want to know when the diarrhea started, whether there were recent feed changes, deworming, travel, new herd additions, medication use, or fever. They will also assess hydration, heart rate, gum color, gut sounds, digital pulses, body condition, and whether your donkey is still eating.

Testing often depends on how sick the donkey appears. Common first-line tests include a CBC and chemistry panel to look for dehydration, inflammation, low protein, electrolyte changes, and organ involvement. Fecal testing may include parasite evaluation, fecal culture, or PCR panels for infectious causes such as Salmonella, clostridial disease, coronavirus, or other regionally relevant pathogens. In some cases, your vet may recommend abdominal ultrasound, rectal exam when appropriate, blood lactate, or repeat manure testing over several days.

If diarrhea is chronic, the workup may broaden to include dental evaluation, diet review, sand assessment, targeted parasite testing, and screening for protein loss or liver disease. Isolation and biosecurity may also be recommended while infectious causes are being ruled out, because some equine diarrhea pathogens can spread to other equids and some, like Salmonella, can pose a human health risk.

Prevention starts with steady management. Make feed changes gradually over at least several days, keep forage quality consistent, and avoid sudden access to rich pasture or large concentrate meals. Clean water should always be available, and feed storage should protect hay and concentrates from mold, contamination, and rodents.

Work with your vet on a targeted parasite control plan rather than routine deworming without testing. Fecal egg counts and periodic review of dewormer effectiveness can help reduce parasite-related diarrhea while slowing resistance. Good manure management, lower stocking density when possible, and minimizing shared contamination around feeders and water sources also help.

Medication review matters too. If your donkey needs antibiotics or NSAIDs, ask your vet about GI risks and what monitoring is appropriate. During illness, transport, weather stress, or appetite changes, act early. Donkeys should not be over-restricted or allowed to go off feed for long because that raises the risk of hyperlipemia. Prompt attention to appetite, manure changes, and hydration is one of the most practical prevention tools a pet parent has.