Strongyle Infections in Donkeys: Bloodworms, Weight Loss, and Worming Concerns

Strongyle infections are intestinal parasite infections caused by bloodworms, a group of nematodes that includes small strongyles (cyathostomins) and large strongyles. In modern equine practice, small strongyles are the most common concern. Donkeys become infected when they graze pasture contaminated with infective larvae passed in manure.

These parasites can irritate the intestinal lining, compete for nutrients, and in some cases trigger inflammation when large numbers of larvae emerge from the gut wall. That can lead to poor body condition, loose manure, colic, and reduced performance. Large strongyles are less common than they once were, but they can still matter because migrating larvae may damage blood vessels that supply the intestines.

Donkeys deserve special attention because they often tolerate parasite burdens quietly. A donkey may look only mildly "off" while carrying a significant worm load. For some pet parents, the first signs are slow weight loss, a rough coat, or a donkey that is not maintaining condition despite adequate feed.

The good news is that strongyle control has moved away from blanket worming and toward smarter, evidence-based care. Your vet can help build a parasite plan that fits your donkey, your pasture setup, and local resistance patterns.

Strongyle infections start when a donkey eats infective larvae while grazing or eating feed contaminated with manure. Eggs are shed in feces, develop on pasture, and are then picked up by other animals. Warm, moist conditions often help larvae survive, so pasture contamination can build over time when stocking density is high or manure management is limited.

Small strongyles are the main ongoing parasite issue in many adult equids. Their larvae can encyst in the intestinal wall, where they may not be detected well by a routine fecal egg count. Later, when many larvae emerge at once, they can cause significant inflammation. Large strongyles are less common today in well-managed herds, but they remain important because larval migration can injure intestinal blood supply.

Several factors increase risk. These include crowded grazing areas, year-round exposure to contaminated pasture, bringing in new animals without quarantine testing, and relying on frequent routine deworming without checking whether the drugs are still effective. Anthelmintic resistance is now a major concern in equine parasite control, so repeated blind treatment can make long-term control harder.

Donkeys also tend to mask illness. Because they may appear stoic, a parasite burden can become established before anyone notices a problem. That is why prevention depends on both pasture hygiene and a testing-based plan made with your vet.

Diagnosis usually begins with a physical exam, body condition assessment, and a review of your donkey's deworming and pasture history. Your vet will often recommend a fecal egg count (FEC) to estimate how many strongyle eggs are being shed. This helps identify higher shedders and can guide whether treatment is needed.

A fecal egg count is useful, but it has limits. It does not reliably measure the number of encysted small strongyle larvae in the intestinal wall, and a low egg count does not always rule out clinically important disease. If your donkey is losing weight, has chronic diarrhea, or has recurrent colic, your vet may also suggest bloodwork to look for inflammation, anemia, dehydration, or low protein levels.

In some cases, your vet may recommend a fecal egg count reduction test (FECRT). This means checking fecal egg counts before and after deworming to see whether the chosen product is still working on your property. That matters because resistance to common dewormers is well documented in equids.

If signs are severe or do not fit a simple parasite picture, your vet may broaden the workup to include dental evaluation, nutrition review, sand testing where relevant, or imaging and additional lab work. Weight loss in donkeys is not always caused by worms, so a full assessment is often the safest approach.

Prevention works best when it combines testing, targeted treatment, and pasture management. Current equine parasite guidelines recommend moving away from fixed, frequent year-round deworming and toward fecal egg counts that identify which animals are shedding more eggs. This helps reduce unnecessary drug use and slows resistance.

Good manure control matters. Removing manure from paddocks regularly, avoiding overstocking, and reducing grazing pressure on contaminated areas can lower exposure. If you manage multiple equids, ask your vet whether rotational grazing, quarantine fecal testing for new arrivals, or separating higher shedders would help on your property.

Work with your vet to build a donkey-specific parasite plan. Donkeys may not show obvious signs even when parasite burdens are meaningful, so periodic monitoring is important. Your vet may recommend seasonal fecal testing, strategic treatment for specific parasites, and follow-up checks to confirm that a dewormer is still effective.

Do not assume that more frequent worming is safer. In many cases, it increases resistance pressure without improving health. A thoughtful plan that matches your donkey's risk, environment, and test results is usually the most sustainable way to protect body condition and gut health.