Methane emissions from sheep

Abstract

A total of 1137 observations from sheep of different age fed with rations of different composition were collected from the literature. This study used measures of methane emissions from sheep under different feeding conditions to compute regression equations to predict methane emissions from ration descriptive variables. It was also tested whether the material validated other common prediction equations. Methane emissions from all sheep averaged 22.15 g day −1. For growing sheep and adult sheep they equalled 23.16 g day −1 and 20.48 g day −1, respectively, with significant differences ( P ≤ 0.05). The percentage loss of methane (% of gross energy intake) averaged 7.22, 7.23 and 7.22%, respectively. Methane emissions increased ( P ≤ 0.05) with increasing live weight, feeding level measured as multiples of maintenance and digestibility of dry matter and decreased for rations with wider ratios of crude fibre intake and intake of N-free extracts. Crude fibre content in the ration and energy density of the ration showed no clearly identifiable effect on methane emissions.