Mycotoxin-Related Liver Disease in Donkeys: Moldy Feed Risks

Mycotoxin-related liver disease is liver injury caused by toxins produced by certain molds growing in feed. In donkeys, the concern is usually contaminated hay, grain, corn, pelleted feed, or bedding exposed to moisture, heat, and poor ventilation. Equids are considered more sensitive than many ruminants to several feed toxins, so even a feed problem that looks minor can matter.

The liver is one of the main organs that processes toxins. When a donkey eats contaminated feed over days or weeks, liver cells can become inflamed, damaged, or die. Aflatoxins are especially known for causing liver injury and clotting problems. Other mycotoxins may cause mixed effects involving the gut, immune system, or nervous system. Because donkeys often hide illness until they are fairly sick, early signs can be easy to miss.

This condition is not contagious from donkey to donkey. The real risk is shared exposure. If one donkey is affected, other animals eating from the same hay lot, grain bin, or round bale may also be at risk. That is why your vet may ask detailed questions about feed storage, recent feed changes, and whether any other animals on the property seem off.

The cause is exposure to mold toxins in feed, not the mold itself alone. Molds such as Aspergillus, Fusarium, and others can grow on grains, corn, hay, haylage, and mixed feeds when moisture and storage conditions allow it. Aflatoxins are the best-known liver toxins in this group. They are associated with liver cell damage, impaired protein production, and bleeding problems. Fumonisins are classically linked to moldy corn poisoning in equids and can cause severe neurologic disease, with liver effects possible in some cases.

Risk goes up when feed is stored in humid conditions, bags are torn, bins are not cleaned, round bales sit in weather, or hay is baled too wet. Feed can also contain mycotoxins even when mold is not obvious. That is important because a clean-looking ration is not always a safe ration.

Donkeys may be exposed through hay, grain, pelleted concentrates, corn byproducts, or even bedding contamination. Long-term low-dose exposure can cause vague, chronic signs. Short-term heavy exposure can cause sudden, severe illness. Your vet will also consider other causes of liver disease, including toxic plants, medications, infectious disease, and metabolic problems, because the signs can overlap.

Diagnosis usually starts with history and pattern recognition. Your vet will ask what your donkey has been eating, whether the feed recently changed, how it is stored, and whether other animals on the property are affected. A physical exam may show jaundice, poor body condition, dehydration, sun-sensitive skin lesions, or neurologic changes.

Bloodwork is a key next step. A chemistry panel can look for liver enzyme changes, bilirubin elevation, low protein, and other clues that the liver is struggling. A complete blood count may help assess inflammation or anemia, and clotting tests may be recommended if bleeding is a concern. In some cases, your vet may add bile acids, ultrasound, or other liver-focused testing.

Feed testing is often one of the most useful pieces of the puzzle. For aflatoxin and many other mycotoxins, testing the suspect hay, grain, or corn is more practical than trying to prove exposure from a live animal sample. If a donkey dies or is euthanized, necropsy and liver histopathology can help confirm the pattern of injury and rule out other causes. Because no single test is perfect, diagnosis often relies on combining clinical signs, liver changes on lab work, and evidence of contaminated feed.

Prevention starts with feed quality and storage. Do not feed hay, grain, corn, or pellets that are musty, clumped, damp, discolored, heating, or visibly moldy. Store feed in a dry, well-ventilated area, keep bags off the floor, clean bins regularly, and rotate stock so older feed is used first. Moisture control matters because molds grow best when feed is stored too wet or becomes damp after purchase.

Inspect every new batch of hay and concentrate before feeding. Be especially careful with corn and corn byproducts, since fumonisins are a major equine concern. If a bale, bag, or bin seems questionable, stop feeding it and contact your vet before offering it to donkeys or other equids. Feed that looks normal can still contain toxins, so a sudden cluster of appetite loss, dullness, diarrhea, jaundice, or neurologic signs after a feed change deserves attention.

If you suspect contamination, isolate the feed lot, save samples, and document lot numbers or purchase dates. Your vet can help decide whether feed testing is worthwhile and whether other animals should be screened. Good storage, careful inspection, and fast action when something seems off are the most practical ways to lower risk.