Estimation of enteric methane emissions from crossbred beef cattle in Vietnam: a case study in quang Ngai province

The objective of this study was to estimate methane (CH₄) emissions from four crossbred cattle groups commonly raised in Vietnam: ½ Belgian Blue cattle (BBB × Lai Brahman), ½ Charolais cattle (Charolais × Lai Brahman), ½ Droughtmaster cattle (Droughtmaster × Lai Brahman), and ½ Red Angus cattle (Red Angus × Lai Brahman), from 6 to 18 months of age (n = 4 per group). All animals were fed the same diet and monitored for feed intake and weight gain. Gross energy intake was calculated, and enteric CH₄ emissions were estimated using the Tier 2 methodology of the Intergovernmental Panel on Climate Change. Dry matter intake, live weight, and enteric CH₄ emissions (kg month⁻¹) increased with age in all groups. The highest values were observed in ½ Charolais, followed by ½ BBB, ½ Red Angus, and ½ Droughtmaster. However, emission intensity (kg CH₄ kg⁻¹ carcass weight or kg CH₄ kg⁻¹ edible protein) was significantly lower in ½ BBB and ½ Charolais compared to ½ Red Angus and ½ Droughtmaster (P < 0.001). Total enteric CH₄ emissions over the 13-month period averaged 67, 69, 61, and 64 kg for ½ BBB, ½ Charolais, ½ Droughtmaster, and ½ Red Angus, respectively. It is concluded that crossbreeding strategies that improve animal productivity can reduce enteric CH₄ emission intensity per unit of product.