Faecal Energy Loss in Ruminants

Correct Answer: 40–50% of GE

In ruminants consuming roughages, faecal energy loss is very high — 40–50% of gross energy intake (GEi). This is because roughages have low digestibility due to high cell wall (cellulose, hemicellulose, lignin) content.

Faecal Energy Loss by Species and Diet

• Ruminants on roughage: 40–50% of GEi
• Ruminants on concentrate: 20–30% of GEi
• Horse: 35–40% of GEi
• Pig: 20% of GEi

Why is Faecal Loss so High in Ruminants on Roughage?

Lignin is completely indigestible. High fibre content = low digestibility = high faecal energy loss. Faecal energy loss is the single largest energy loss in ruminants, which is why 'improving roughage digestibility' (e.g., urea treatment) is so important.