💩 Vet Guide 2025: Understanding and Managing Chronic Diarrhea in Horses 🐴🧬

Author: Dr Duncan Houston, BVSc

Chronic diarrhea in horses can be one of the most frustrating and difficult conditions to diagnose and manage. Often, these horses appear otherwise healthy, but continue to suffer from persistent or intermittent loose manure that doesn't resolve with basic changes. In this 2025 vet guide, Dr Duncan Houston walks through the potential causes, modern diagnostics, and treatment options for chronic diarrhea. 🐎🔍

🔬 Why Is It So Hard to Diagnose?

Chronic diarrhea has many possible causes, and unfortunately, 30% of cases remain undiagnosed even after extensive testing. Horses may show no other signs of illness, making the process even more challenging. 🧪

Diagnostic Tools and Tests:

• 🩺 Basic bloodwork to assess systemic health
• 🧫 Fecal egg counts to check for parasite load
• 🧪 Equine diarrhea panel (identifies pathogens like Salmonella)
• 🧲 Rectal exam and rectal biopsy
• 🧬 Glucose absorption test for malabsorption syndromes
• 🪨 Sand accumulation test (e.g., fecal sediment test)

Even with advanced tools, many horses present with nonspecific or inconclusive results. Persistence and careful vet guidance are critical. 🔄

🦠 Common and Uncommon Causes

1️⃣ Parasitism

• 🐛 Strongyle infections are a common cause
• 🧫 Fecal testing helps guide targeted deworming

2️⃣ Sand Accumulation

• 🏜️ Sand irritates and inflames the intestinal lining
• 🧪 Easily tested and treated with psyllium fiber therapy

3️⃣ Inflammatory Bowel Disease (IBD) or Lymphoma

• 🧬 Require biopsy for diagnosis—often rectal samples are used
• ⚠️ Can be difficult and costly to confirm

4️⃣ Malabsorption Syndromes

• 🧪 Diagnosed via glucose absorption test
• 🩺 Reflects poor nutrient uptake in the small intestine

5️⃣ Intestinal Dysbiosis

• 🦠 Disruption of the gut microbiome
• 📉 May result from overuse of antibiotics or chronic stress

🛠️ Treatment Options in 2025

1️⃣ Prebiotics and Probiotics

• 🔬 Results are mixed—some horses benefit, others do not
• 🛡️ Best used as part of a broader management plan

2️⃣ Fecal Transplant (Fecal Microbiota Transfusion)

• 💩 Administered via nasogastric tube from a healthy donor horse
• 🧬 Helps restore healthy intestinal flora

3️⃣ Nutritional Adjustments

• 🍚 Feed low-starch, high-fiber diets
• 🌿 Eliminate known allergens or irritants
• 💧 Ensure consistent access to clean water

4️⃣ Medications

• 💊 Anti-inflammatories (e.g., corticosteroids for IBD)
• 🔬 Antimicrobials (targeted if bacterial pathogens are confirmed)

🧠 Dr Duncan Houston’s Insight

"Chronic diarrhea is not just messy—it signals that something’s wrong. Diagnosing the root cause takes time, testing, and often a bit of trial and error." 🐴🧠

📋 When to Call Your Vet

Always consult your veterinarian if:

• 💩 Diarrhea lasts more than a week
• 📉 There is weight loss or a change in attitude
• 🩺 Blood or mucus appears in the manure

Chronic diarrhea can become debilitating if untreated. Timely action improves the odds of resolution. 🕒

🔚 Final Word: Don’t Ignore Loose Manure

Chronic diarrhea may not always mean disease, but it’s never “normal.” Whether the cause is infectious, inflammatory, or metabolic, a structured diagnostic approach is key. Work closely with your veterinarian to explore options and find relief for your horse. 🐎❤️

Need expert support? Visit AskAVet.com or download the Ask A Vet app for help with chronic GI issues. 📱🧬