Roundworms in Donkeys: Ascarid Infection in Young Donkeys and Foals

Quick Answer
  • Roundworms in donkeys are usually caused by Parascaris species, large intestinal worms that affect foals and young donkeys more often than healthy adults.
  • Many young donkeys have mild signs at first, but heavier burdens can cause a rough hair coat, pot belly, poor growth, cough, nasal discharge, or colic.
  • See your vet promptly if a foal has belly pain, repeated rolling, trouble breathing, fever, or passes worms in manure, because severe infections can lead to intestinal blockage or rupture.
  • Diagnosis usually involves a fecal egg count plus age, history, and exam findings. A negative fecal test does not always rule out early infection.
  • Typical US cost range for exam, fecal testing, and a basic treatment plan is about $80-$250. Cases with colic, ultrasound, hospitalization, or surgery can rise to $800-$5,000+.
Estimated cost: $80–$250

What Is Roundworms in Donkeys?

Roundworms in donkeys usually refers to ascarid infection, most often caused by Parascaris species. These are large intestinal parasites of equids, including donkeys, horses, and zebras. Young animals are the main group at risk because they have not yet developed much natural resistance. In foals and weanlings, the worms can build up in the small intestine and sometimes cause serious disease.

After a young donkey swallows infective eggs from contaminated pasture, bedding, feed, or water, the larvae migrate through the body before returning to the intestines to mature. During that migration, some foals develop coughing or nasal discharge. Once the worms are established in the gut, they may contribute to poor growth, a dull coat, weight loss, or a pot-bellied appearance.

Many infections are mild, especially early on. The concern is that heavy worm burdens can become dangerous, particularly in young donkeys and foals. Large numbers of worms may trigger colic, intestinal blockage, or, in severe cases, intestinal rupture. That is why parasite control in young equids should be planned with your vet rather than handled with a one-size-fits-all schedule.

Although most research and treatment guidance comes from horses, the same parasite principles are generally applied to donkeys. Your vet may adjust the plan based on the donkey’s age, body condition, housing, pasture hygiene, and local parasite resistance patterns.

Symptoms of Roundworms in Donkeys

  • Poor growth or failure to thrive in foals and young donkeys
  • Pot-bellied appearance
  • Dull or rough hair coat
  • Weight loss or poor weight gain
  • Intermittent cough, especially in young animals
  • Nasal discharge during larval migration
  • Mild fever or reduced energy
  • Soft manure or digestive upset
  • Visible worms in manure in heavier infections
  • Colic signs such as pawing, looking at the flank, stretching out, or rolling
  • Reduced appetite
  • Severe cases: abdominal distension, breathing difficulty, or signs of intestinal blockage

Mild roundworm infections may be easy to miss at first. A young donkey might only seem a little thin, have a rough coat, or grow more slowly than expected. Respiratory signs like coughing can happen while larvae are migrating, so some foals show lung-related signs before obvious digestive problems appear.

See your vet immediately if your donkey has colic signs, repeated rolling, marked belly swelling, trouble breathing, weakness, or stops eating. Those signs can point to a heavy parasite burden or a complication such as intestinal impaction, which needs urgent veterinary care.

What Causes Roundworms in Donkeys?

Roundworms spread when a donkey swallows infective eggs from the environment. These eggs are passed in manure, then develop outside the body and can survive for long periods in paddocks, stalls, feeders, and other contaminated areas. Young donkeys are especially vulnerable because they explore with their mouths and have less immunity than adults.

Crowded housing, poor manure removal, feeding on the ground, and repeatedly using the same foaling or nursery areas can all increase exposure. Eggs are sticky and hardy, so they can build up over time in places where foals live. Even well-cared-for young donkeys can become infected if the environment is heavily contaminated.

Another important factor is anthelmintic resistance, meaning some dewormers may not work as well as expected on a given farm. In equids, Parascaris resistance to certain drug classes has become a real management issue. That is one reason current parasite control guidance favors fecal monitoring and targeted plans instead of blind, frequent rotation.

Adult donkeys may carry lower burdens and show few signs, but they can still contribute to pasture contamination. Your vet can help build a herd-level plan that considers both the young donkey and the environment around it.

How Is Roundworms in Donkeys Diagnosed?

Diagnosis usually starts with a physical exam, age history, deworming history, and a discussion of symptoms. Your vet will often recommend a fecal egg count or fecal flotation to look for parasite eggs. This can help identify shedding animals and guide treatment choices, but it has limits. Early larval stages do not produce eggs yet, and egg counts do not always match the total number of adult worms present.

Because of that, your vet may diagnose suspected ascarid disease based on the whole picture rather than a test result alone. A young donkey with poor growth, cough, pot belly, and a high-risk environment may still need a treatment plan even if the first fecal test is not strongly positive.

If a foal has colic, belly distension, or concern for obstruction, your vet may recommend additional testing such as bloodwork, abdominal ultrasound, or referral for hospital care. In some cases, worms are seen in manure after treatment, which supports the diagnosis.

For farms with repeated parasite problems, your vet may also suggest a fecal egg count reduction test after treatment. This checks whether the chosen dewormer is working well on your property and can help shape future prevention plans.

Treatment Options for Roundworms in Donkeys

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$80–$180
Best for: Stable young donkeys with mild signs, no colic, and pet parents seeking evidence-based care with close home follow-up
  • Farm or clinic exam
  • Fecal egg count or fecal flotation
  • Weight-based deworming plan chosen by your vet, often using a benzimidazole when ascarids are suspected in young equids
  • Home monitoring for manure output, appetite, cough, and colic signs
  • Basic pasture and stall hygiene guidance
Expected outcome: Often good when infection is caught early and the donkey remains bright, eating, and passing manure normally.
Consider: Lower upfront cost, but it relies on careful monitoring at home. It may not be enough if the worm burden is heavy, if resistance is present, or if the donkey develops colic after treatment.
Most Common

Recommended Standard Treatment

$180–$450
Best for: Most young donkeys and foals with suspected or confirmed roundworms as a first-line veterinary approach
  • Exam plus fecal testing
  • Individualized deworming plan based on age, parasite risk, and local resistance concerns
  • Repeat fecal testing or fecal egg count reduction follow-up
  • Supportive care recommendations such as hydration, feeding changes, and exercise restriction if needed
  • Recheck visit or phone follow-up with your vet
Expected outcome: Good in many uncomplicated cases, especially when treatment is timed appropriately and the environment is cleaned up to reduce reinfection.
Consider: Costs more than a basic visit, but gives better follow-up and a more tailored parasite control plan. Multiple visits or repeat testing may be needed.

Advanced / Critical Care

$800–$5,000
Best for: Foals or young donkeys with severe colic, abdominal distension, reduced manure output, weakness, or concern for intestinal obstruction
  • Urgent exam for colic, respiratory distress, or suspected intestinal blockage
  • Bloodwork and abdominal ultrasound
  • Nasogastric intubation, IV fluids, pain control, and hospital monitoring when needed
  • Referral care for impaction or rupture risk
  • Surgery in severe obstructive cases
Expected outcome: Guarded to good depending on how quickly the problem is recognized and whether there is an obstruction, rupture, or other complication.
Consider: Most intensive and highest cost range. It can be lifesaving in severe cases, but travel, hospitalization, and surgery add stress and expense.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Roundworms in Donkeys

Bring these questions to your vet appointment to get the most out of your visit.

  1. You can ask your vet whether my donkey’s age and symptoms fit ascarid infection or another parasite problem.
  2. You can ask your vet which fecal test is most useful right now and what its limits are in a young foal.
  3. You can ask your vet which dewormer class makes the most sense on our farm based on local resistance concerns.
  4. You can ask your vet whether treatment should be staged or adjusted to lower the risk of a worm impaction in a heavily infected foal.
  5. You can ask your vet what warning signs mean I should call right away after deworming, especially colic or reduced manure output.
  6. You can ask your vet how often this donkey should have fecal egg counts during the first year of life.
  7. You can ask your vet what manure removal, feeding, and pasture changes would most reduce reinfection on our property.
  8. You can ask your vet whether other donkeys or horses on the farm should be tested or treated at the same time.

How to Prevent Roundworms in Donkeys

Prevention focuses on reducing environmental contamination and using dewormers thoughtfully. Remove manure from stalls, dry lots, and small paddocks regularly. Avoid feeding hay or grain directly on the ground when possible. Keep water sources clean, and pay special attention to foaling and nursery areas where young donkeys spend time.

Young donkeys and foals usually need a more structured parasite plan than healthy adults. Current equine guidance supports targeted treatment for ascarids in foals, often around 2 months and 5 months of age, with follow-up based on fecal monitoring and your vet’s judgment. Fixed, frequent deworming without testing is no longer favored because it can worsen drug resistance.

Pasture management matters too. Do not overcrowd paddocks, and if practical, rotate grazing areas or cross-graze with non-equid livestock to reduce equine parasite exposure. New arrivals should be discussed with your vet before they join the group, especially if their parasite history is unknown.

The best prevention plan is herd-based, not just individual. Ask your vet to help you build a donkey-specific parasite control program that includes fecal egg counts, age-based treatment timing, and realistic sanitation steps for your farm.

Find a Vet Near You