Methane emission factors for beef cows in Argentina: effect of diet quality

Abstract

To determine the methane (CH4) emission factors for beef cows in Argentina, we carried out two experiments to test the effect of different diets on methane emission from grazing conditions. In experiment 1, diet consisted of native grass-based pasture vs. sorghum-based pasture (63.1% and 63.5% of dry matter digestibility (DMD) respectively), and in experiment 2, it consisted of native grass-based pasture vs. alfalfa hay (45.2% and 43.6% of DMD respectively). In both experiments, CH4 production showed statistically significant differences (202.7 ± 11.5 and 157.5 ± 10.6 g/d for native grass-based pasture and sorghum respectively; 157.4 ± 8.9 and 190.6 ± 9.4 g/d for native grass-based pasture and lucerne hay respectively). The energy lost through eructation of CH4 was less for cows grazing sorghum than for cows grazing native grass-based pasture (4.3% ± 0.3% vs 5.6% ± 0.4%), and it was similar between the latter and cows grazing alfalfa hay (7.1% ± 0.6% vs 8.2% ± 0.5%). The results support that low quality diets increase methane yield (Ym).