Methane emission by growing pigs and adult sows as influenced by fermentation

The fermentation of carbohydrates in pigs' digestive system, especially in the lower gut results predominantly in short chain fatty acids, gasses as CO₂, H₂ and CH₄. Methane (CH₄) is especially interesting as it contributes to the greenhouse gas emission and thus also to the global warming. CH₄ production and its relation to fermentation in growing pigs (74 diets) as well as adult sows (36 diets), were investigated in diets varying greatly in chemical composition. All diets were assayed in digestibility and energy balance experiments in respiration chambers. Growing pigs fed diets varying in total fibre content (2.8–40%) had a CH₄ production equivalent to 0.1 to 1.3% of digested energy (DE). Non-lactating sows fed at maintenance had a CH₄ production equivalent to 0.4 to 3.3 % of DE. Intensively fed lactating sows had the lowest CH₄ production (about 0.6% of DE). In general, the production of methane depended on fibre origin, however high variation was found between animals.