Energy Loss as Methane in Ruminants

Correct Answer: 7–9% of GE

In ruminants, microbial fermentation in the rumen produces methane (CH₄) and CO₂ in the ratio of 35:65. This methane represents a real energy loss to the animal — it is simply belched out.

Key Facts About Methane Energy

• Methane loss = 7% of GE (standard value used in energy partitioning)
• Gross energy of methane = 13.34 kcal/g
• Gas production rate in cow = 30 litres/hour
• Gas composition: CO₂ : CH₄ = 65 : 35

Energy Partitioning in Ruminants

GE → (−Faecal energy 40–50%) → DE → (−Urinary energy 4–5%, −CH₄ 7%) → ME → (−Heat increment) → NE → NEm + NEp

Why is Methane Reduction Important?

Ionophore antibiotics like Monensin (Rumensin) and Lasalocid (Bovitec) decrease CH₄ production by inhibiting methanogenic bacteria and shifting fermentation toward propionate.