Greenhouse gas emission intensity from grazing beef steers with or without supplement in Argentina

RICCI, P.; TESTA, M.L.; ALONSO RAMOS, S. ; MAGLIETTI, C.; PAVÁN, E.; LOMBARDI, B.; ALVARADO, P.I.; GUZMÁN, S.; JULIARENA, P; GONDA, H.

Foz do Iguassu

Conferencia; 7th International Greenhouse Gas and Animal Agriculture Conference; 2019

EMBRAPA

Beef production is a major industry in Argentina, but it is also responsible for the emissions of Greenhouse gases (GHG). The aim of the study was to measure the impact of supplementing grazing beef steers on their GHG emissions intensity. Twenty Angus steers (200 ± 10 kg) grazed tall fescue and alfalfa pasture without (P) or with maize grain as daily supplement (S, 1% body weight) during 90 days. Body weight was recorded every 21 days. Enteric methane (CH4) was measured on days 85 to 90 (SF6 technique). Methane and nitrous oxide (N2O) emissions from dung patches were measured using close static chambers (n = 5). Total CO2eq was equal to (enteric CH4 + dung CH4) * 25 + dung N2O * 298. Average daily body weight gain (ADG) was 0.38 vs. 0.55 kg and enteric CH4 was 4,045 and 4,300 g CO2eq?anim-1?d-1 for P and S, respectively. Methane emission from dung patches decreased from 64.9 to 21.3, but N2O increased from 19.9 to 60.4 g CO2eq?anim-1?d-1 for P and S, respectively. Although total emissions from P were numerically lower than S steers (4,130 and 4,382 g CO2eq?anim-1?d-1, respectively), total emission intensity were reduced by 27% (10.87 vs. 7.97 kg CO2eq?kg ADG-1, respectively) due to a 45% higher performance of supplemented steers. Although emissions from urine patches are still needed, this study demonstrated with local information that supplementing grazing steers have substantial impacts on improving productivity without altering enteric plus dung GHG emissions.