🍼 Vet Guide 2025: Diarrhea in Newborn Foals—What’s Normal, What’s Not 🐴💩

Author: Dr Duncan Houston, BVSc

Diarrhea in newborn foals can send any horse owner into panic mode. But the truth is, not all foal diarrhea signals disease. In many cases, it's a normal part of early development—especially during what’s commonly called “foal heat diarrhea.” In this 2025 guide, Dr Duncan Houston explains what causes diarrhea in young foals, what to monitor, and when to seek veterinary help. 🐎🧠

🔬 What Causes Diarrhea in Foals?

Newborn foal diarrhea can stem from:

• 🧪 Inflammation in the gastrointestinal tract
• 🔁 Changes in gut motility
• 💧 Increased fluid secretion in the intestines
• 🦠 Infections (bacterial, viral, or parasitic)

In many foals, diarrhea occurs during the first few weeks of life without any underlying disease. This is often due to normal gut maturation. 🧬

🧼 Risk Factors for Neonatal Foal Diarrhea

• 🪵 Using wood shavings as stall bedding
• 💊 Early use of antibiotics in foals
• 🚿 Lack of hygiene during foaling (e.g., dirty mare udder or tail)

✅ Prevention tips include:

• 🧽 Washing the mare’s udder and tail before foaling
• 🧴 Disinfecting foaling stalls thoroughly
• 🌿 Foaling on pasture when possible

🍼 What Is Foal Heat Diarrhea?

Foal heat diarrhea is a common, self-resolving condition in foals aged 5 to 21 days. It’s not caused by the mare's heat cycle, milk changes, or parasites as once believed. Instead, it's now linked to:

• 🧬 Maturation of the foal’s gut and microbiome
• 🍂 Initial ingestion of hay, grain, or grass
• 💩 Ingestion of small amounts of the dam’s manure

Most foals with foal heat diarrhea remain bright, active, and continue nursing. No treatment is required unless other symptoms arise. 🩺

📋 When to Call the Vet

Although most foal diarrhea is mild and harmless, call your veterinarian if you see:

• 📉 Lethargy or weakness
• 🚱 Refusing to nurse
• 💧 Signs of dehydration (sunken eyes, dry gums)
• 🔥 Fever
• 🩸 Blood or mucus in the diarrhea

💡 Some foals may become dehydrated even from mild diarrhea and may require fluid therapy to support recovery. Early action prevents complications. ⏱️

🧠 Dr Duncan Houston’s Advice

"Don’t panic at every loose stool—watch the foal’s attitude, hydration, and appetite. Foal heat diarrhea is common and usually harmless." 🐴🧠

🌱 Management Tips to Support Foal GI Health

• 🧼 Keep the foaling environment clean and dry
• 🧽 Wash mare’s udder and tail regularly
• 🌿 Allow supervised pasture turnout for natural GI development
• 🩺 Avoid unnecessary early antibiotic use

🔚 Final Word: Know What’s Normal

Diarrhea in newborn foals can be alarming, but it’s often a sign of normal gut development. By understanding the difference between foal heat diarrhea and more serious causes, you can act appropriately and protect your foal’s health. 🐎❤️

Have questions about foal care? Visit AskAVet.com or download the Ask A Vet app for 24/7 veterinary support. 📱🍼