Yearly methane emissions of digestive origin by sheep, goats and equines in France. Variations with physiological stage and production type

Abstract

Daily methane emissions by herbivorous according to species, physiological stage, diet composition and feeding level could be predicted from the results of methane production determined using respiration chambers. Yearly methane emissions by sheep, goats and equines in France were calculated, as for cattle, from recommended energy allowances, taking into account the various types and levels of animal production, variations in feeding regimen along the year and the number of animals of each category in 1994.

Mean yearly methane emissions of a suckling ewe (16.7 m³) or a dairy ewe (17.8 m³) are close to that of a dairy goat (22.9 m³). They amount to 13 % of those of a suckling cow and a dairy cow, respectively. Methane emission of a ewe lamb is similar to that of a young goat (8 m³/year). However, it is three times higher for a grazing lamb (2.9 m³/year) than for an indoor fattened early-weaned lamb.

Methane emissions per kg milk average 77, 38 and 30 l in dairy ewes, goats and cows, respectively. They average 60 and 1160 l per kg cold carcass from indoor fattened and grass lambs, respectively, and 300, 580 and 1040 l/kg for dairy and beef bullocks and 40 month-old beef steers, respectively, including methane production of the dam for meat breeds.

Methane production per kg feed is 3 to 4 times smaller in equines than in ruminants. Yearly methane emissions from equines average 23 to 27 m³ for saddle horses, 42 m³ for draught studes and 14 to 20 m³ for ponies.

Total methane emissions by herbivorous in France amount to slightly more than 2 thousand millions m³ per year, of which 91 % from cattle, 7 % from sheep, 1 % from goats and 0.5 % from equines.