How To Get EPM Horses To Feed: A Technical Guide To Medication And Nutritional Compliance

Successful management of Equine Protozoal Myeloencephalitis (EPM) relies on the precise, daily administration of antiprotozoal medications alongside a high-calorie, neuro-supportive diet. To ensure a horse with neurological deficits maintains a steady intake, caregivers must utilize pharmaceutical masking agents, optimize caloric density with Vitamin E supplementation, and adapt delivery methods based on the horse’s specific cranial nerve function and appetite levels.

Pre-Treatment Requirements and Nutritional Foundations

Before initiating an EPM treatment protocol, it is essential to understand that the disease, caused by Sarcocystis neurona or Neospora hughesi, often impacts a horse’s appetite through secondary stress or direct neurological impairment of the cranial nerves involved in chewing and swallowing (dysphagia). The goal is not merely to "get the horse to eat," but to ensure the full bioavailable dose of medication—whether Ponazuril, Diclazuril, or Sulfadiazine/Pyrimethamine—is consumed without waste.

Effective management requires a preparation phase that stabilizes the horse’s environment and gathers the necessary materials for high-compliance feeding.

Essential Equipment and Materials

• Medical Delivery Tools: 60cc catheter-tip syringes for oral dosing, or wide-bore dosing syringes for thick pastes.
• Palatability Enhancers: Unsweetened applesauce, blackstrap molasses, peppermint oil, or alcohol-free carrot juice.
• High-Quality Supplements: Natural Vitamin E (RRR-alpha-tocopherol) in liquid or water-soluble form (standard dose: 5,000 to 10,000 IU daily).
• Feeding Receptacles: Shallow, wide rubber tubs to prevent "tossing" of feed and to make it easier for neurologically uncoordinated horses to reach their grain.
• Weight Monitoring Tools: A weight tape or calibrated scale to monitor muscle wasting (atrophy), which is a primary clinical sign of EPM.

Prerequisite Standards

• Veterinary Diagnosis: Confirmation via IFAT or SAG 2, 4/3 ELISA testing to determine the specific protozoal load.
• Neurological Grading: Assessing the horse on the Mayhew Scale (0-5) to determine the risk of falling or aspiration during feeding.
• Dental Clearance: Ensuring the horse does not have sharp enamel points or malocclusions that exacerbate the difficulty of eating while neurologically impaired.

Step-by-Step Strategy for Medication Compliance and Feeding

Step 1: Assess Cranial Nerve Function and Swallowing Safety

Before attempting to force-feed or syringe medication, you must determine if the horse can safely swallow. EPM can affect the glossopharyngeal (IX) and vagus (X) nerves, leading to dysphagia. Observe the horse eating a small amount of soaked hay or a mash. Look for "quidding" (dropping partially chewed boluses) or fluid returning through the nostrils.

• If the horse shows signs of aspiration or inability to swallow, consult a veterinarian immediately regarding nasogastric intubation.
• For horses with mild deficits, proceed with a "head-neutral" feeding position to minimize the risk of the medication entering the trachea.

Warning: Never elevate a neurological horse’s head excessively during syringing. This significantly increases the risk of aspiration pneumonia, a common and often fatal complication in EPM cases.

Step 2: Selecting and Preparing the Delivery Vehicle

EPM medications often have a bitter or chemical taste that triggers "feed refusal." To overcome this, you must choose a delivery vehicle that masks the flavor without interfering with drug absorption.

1. For Paste Medications (e.g., Marquis/Ponazuril): These are generally pre-measured. If the horse rejects the tip of the syringe, mix the paste with a small amount of molasses and smear it onto a piece of whole-grain bread or a hollowed-out apple.
2. For Pelleted Medications (e.g., Protazil): These are top-dressed. If the horse sorts through the grain and leaves the pellets, create a "sticky" mash using warm water and beet pulp. The pellets will adhere to the fiber, making it impossible for the horse to separate them.
3. For Liquid/Compounded Suspensions: These are often the most difficult to administer. Mix the dose with 20cc of unsweetened applesauce or pureed carrots in a catheter-tip syringe.

Step 3: Implementing the "Negative Association" Mitigation Technique

Horses are highly sensitive to routine. If every time you enter the stall you "gear up" to force a syringe into their mouth, they will quickly become head-shy and refuse all feed in your presence.

• The Sandwich Method: Offer a handful of unmedicated, highly palatable treats (like alfalfa cubes or carrots) before the medication. Administer the medication quickly and efficiently. Immediately follow with another high-value treat.
• Flavor Rotation: Switch masking agents every 3–4 days. Use peppermint one day and butterscotch or cherry extract the next to prevent the horse from associating a single flavor with the medication.

Step 4: Maximizing Caloric Density and Neuro-Support

EPM causes rapid muscle atrophy, particularly in the topline and hindquarters. To "get the horse to feed" effectively, the diet must be concentrated so they get more nutrition in fewer bites, as neurological fatigue can cause them to stop eating mid-meal.

• Amino Acid Supplementation: Ensure the feed contains high levels of Lysine, Methionine, and Threonine to support muscle repair.
• Fat Over Starch: Use rice bran or vegetable oils to increase calories. High-starch diets can lead to excitability, which is dangerous for an uncoordinated (ataxic) horse.
• Vitamin E Loading: Research suggests that Vitamin E crosses the blood-brain barrier and helps mitigate the oxidative stress caused by the protozoal infection. Administer 10,000 IU for the first 14 days, then taper as directed by a vet.

Pro-Tip: Use water-soluble Vitamin E (such as Nano-E) rather than powder. Water-soluble versions have significantly higher bioavailability in the horse's system, especially when the digestive tract is stressed.

Step 5: Monitoring Environmental Barriers

Sometimes the reason an EPM horse won't feed isn't the food itself, but the environment. Ataxic horses often feel insecure on slippery surfaces or in crowded spaces.

1. Floor Surface: Ensure the feeding area has high-traction rubber mats. If a horse feels they might slip while reaching for a low feeder, they will stop eating.
2. Bucket Height: Adjust the feeder to chest height. Lowering the head too far can shift the center of gravity, making an ataxic horse feel unstable.
3. Isolation vs. Company: While some horses eat better with "neighbors," an EPM horse may feel threatened by dominant horses during mealtime. Provide a quiet, private area for feeding to lower cortisol levels.

Technical Specifications for EPM Medications and Feed Management

The following table outlines the most common pharmacological interventions and the technical considerations for ensuring successful ingestion and absorption.

Troubleshooting Common Feeding Failures

When a horse continues to refuse feed or medication despite your best efforts, look for these specific root causes and apply the corresponding fixes.

• Scenario: The horse "pockets" the medication in its cheek and spits it out later.

  
  
  
  • Root Cause: Poor syringing technique or the horse has learned to hold its breath and tongue to prevent swallowing.
  • Actionable Fix: Insert the syringe into the "interdental space" (the gap between the front and back teeth). Angle the syringe toward the back of the tongue. After depressing the plunger, gently hold the horse's chin up and tickle the roof of the mouth or the throat to stimulate the swallowing reflex.

• Scenario: The horse develops loose stool and stops eating grain entirely.

  
  
  
  • Root Cause: "Dysbiosis" or gastric upset caused by the medication or the stress of the disease.
  • Actionable Fix: Introduce a high-quality probiotic and a hindgut buffer. If the horse is on Rebalance (Sulfadiazine/Pyrimethamine), be aware that long-term use can interfere with folate metabolism; consult your vet about folic acid or specialized yeast cultures.

• Scenario: The horse is interested in food but cannot physically chew.

  
  
  
  • Root Cause: Neurological impairment of the trigeminal (V) or facial (VII) nerves.
  • Actionable Fix: Switch to a "complete feed" pellet that can be completely soaked into a soupy consistency (slurry). This allows the horse to "slurp" the nutrition without requiring significant mastication power.

• Scenario: The horse refuses feed only when the Vitamin E supplement is added.

  
  
  
  • Root Cause: The smell of synthetic carriers or the texture of the oil is unpalatable.
  • Actionable Fix: Switch to a flavorless, water-soluble Vitamin E or hide the supplement inside a hollowed-out piece of carrot or a "dimpled" horse treat designed to hold medication.

Frequently Asked Questions

Can I mix EPM medication with a large meal of grain?

It is generally not recommended to mix EPM medication with a full meal because if the horse does not finish the entire portion, they will not receive a therapeutic dose. Instead, mix the medication with a very small "pre-meal" (about one cup of tasty mash) to ensure the entire dose is consumed immediately before offering the rest of the ration.

How long does it take for a horse’s appetite to return after starting EPM treatment?

Most owners see an improvement in "brightness" and appetite within 7 to 10 days of starting antiprotozoal therapy as the parasite load begins to decrease. However, if the appetite does not improve within two weeks, you should screen for gastric ulcers, which frequently occur secondary to the stress of neurological disease.

Is it safe to use corn oil to help the horse gain weight during EPM recovery?

While corn oil provides calories, it is high in Omega-6 fatty acids, which can be pro-inflammatory. For a horse dealing with neurological inflammation, it is better to use flaxseed oil or camelina oil, which provide a better Omega-3 to Omega-6 ratio to support the immune system and reduce systemic inflammation.

My horse is on Rebalance and seems very tired; should I change the feeding?

Rebalance (Sulfadiazine/Pyrimethamine) can sometimes cause anemia or low white blood cell counts over long periods. If your horse is lethargic and not feeding well, ask your veterinarian for a Complete Blood Count (CBC). You may need to supplement with a specific B-vitamin complex or adjust the dosing schedule.

Can I give Vitamin E at the same time as the EPM medication?

Yes, giving Vitamin E alongside antiprotozoal medication is common practice and generally does not interfere with the absorption of the drugs. In fact, some practitioners believe the presence of a small amount of fat (like that found in some Vitamin E carriers) may actually assist in the absorption of lipophilic drugs like Ponazuril.

Optimize Your Equine Recovery Protocol

Implementing a structured feeding and medication schedule is the most significant factor in overcoming the neurological challenges of EPM. By prioritizing palatability and monitoring neurological swallowing safety, you provide your horse with the nutritional foundation required for long-term health and mobility.