Scenarios for Reducing Enteric Methane Emission from Small Scale Dairy Production Farms in Ba Vi, Ha Noi

Abstract

      An investigation was conducted to study the impact of alternative feeding practices on productivity and cattle enteric methane emissions of smallholder dairy systems in Ba Vi, Ha Noi. The study included two phases. During the first phase, data was collected in 30 farms in Ba Vi, Ha Noi through a semi-structured questionnaire. Average farm size (Mean± SD) was 0.85 ± 0.50 ha (15% crop area) and ~ 9 heads of pure and crossbred Holstein Friesian cattle. Herd structure consisted of 11, 25, 17 and 47% of calves, heifers, dry and lactating cows, respectively. Annual milk

yield/farm was 28,655 ± 16,035 L (~US$ 20,059). Daily milk yield/cow was 14.1 ± 2.9 L. Using the feed supplied in each farm, the Ruminant model estimated yearly cattle enteric methane emission of 590 ± 359 kg per farm, 14.8 ± 8.99 tones CO₂eq/farm and 0.52 ± 0.14 kg CO₂eq/L/milk. In the second phase, data was computed using a fixed representative farm to estimate responses to different feeding practices. Results showed that in comparison with Nepier grass (Pennissetum purpureum) and Guinea (Panicum maximum) or maize (Zea mays; 50% DM of the diet), the use of Ruzzi (Brachiaria ruziziensis) grass improved milk yield up to 14% and reduced enteric methane efficiency up to 9.4%. Potential increase of milk yield (5.3%) and decreased enteric methane efficiency up to 3.6% were predicted when maize silage substituted 50% of the elephant grass.