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Reducing Greenhouse Gas Emissions from Livestock and Soils

Citation

Mitigation of methane emission by means of oil and nitrate supplement in diets of growing cattle

Tran Hie, Dang Vu Hoa* and Nguyen Xuan Trach 

Faculty of Animal Sciences and Aquaculture,  Hanoi University of Agriculture,  Vietnam
hiep26@yahoo.com
*National Institute of Animal Sciences,  Hanoi, Vietnam

Abstract

The objective of the study was to determine methane emission and to mitigate methane emission by oil and nitrate supplement in the diets of growing cattle. An experiment was carried out during 3 months (June - August) in the experimental station of Hanoi University of Agriculture (Vietnam). Twenty-two growing cattle (170 kg on average) were equally devided 8 blocks corresponding to 8 diets based on 2% NaOH treated rice straw and cassava leaf meal (1% BW, DM basic), supplemented with 1.5%, 3.0%, 4.5%, 6.0% sunflower oil plus 4%CaNitrate or 1.5% urea as NPN source. Methane emission was determined by using CH4/CO2 ratio method.

Methane emission rate (liters/kg DMI) was reduced by 26% by nitrate supplement compared with urea supplement (Figure 1). The increase in oil level reduced non-linearly methane emissions. The best level of oil supplement was 3.0% (Figure 2). However, the best treatment was found with 4% CaNitrate and 1.5% oil supplement in the diet (Figure 3). It was also shown that estimated energy loss from the experimental diet ranged from 5 to 8% of diet gross energy, compared with around 12% potential energy loss from diet without supplement. As a conclusion, nitrate and oil supplement (at a limit of 1.5%) can be used to mitigate methane emission from growing cattle. 

Keywords: Greenhouse gases, fecal NIRS,
 

Figure 1. Effect of urea and nitrate supplement on methane emission (U1.5 is 1.5% urea level (on DM basis) (C4.0 is 4.0% calcium nitrate level  on DM basis)

Figure 2. Effect of oil supplement on methane emission (O1.5, O3.0, O4.5 and O6.0 are 1.5%, 3.0%, 4.5% and 6.0%  oil level (on DM basis)

  
   

Figure 3. Interaction effect of oil and NPN supplement on methane emission (U1.5 is 1.5% urea level on DM basis; C4.0 is 4.0% calcium nitrate level on DM basis, O1.5, O3.0, O4.5 and O6.0 are 1.5%, 3.0%, 4.5% and 6.0%  oil level on DM basis)