Greenhouse gas emission intensity based on lifetime milk production of dairy animals, as affected by ration-balancing program

Abstract

Smallholder dairying in India and other developing countries relies on low- and medium-productive animals, and the feeding is mainly based on crop residues and other agro-industrial by-products. The diets are generally nutritionally imbalanced, resulting in productive and reproductive inefficiencies. This also negatively affects the emission intensity (Ei). For the past 3 years, the National Dairy Development Board of India has been implementing large-scale ration-balancing (RB) program in field animals. The effect of feeding balanced rations on Ei was explored. A cradle to farm-gate life-cycle assessment, taking into account the lifespan milk production, was conducted on 163 540 lactating cows and 163 550 buffaloes in northern, southern, eastern and western India. The life-cycle assessment boundary included feed production, enteric fermentation and manure management during various stages of life. On the basis of economic allocation, emissions of methane (CH4) from enteric fermentation, CH4 from manure management, nitrous oxide from manure management and greenhouse gas (GHG), i.e. carbon dioxide (CO2), CH4 and nitrous oxide from feed production, contributed 69.9%, 6.3%, 9.6% and 14.2% in cows, and 71.6%, 7.4%, 12.6% and 8.4% in buffaloes, respectively, to the baseline (before RB) lifetime total GHG emissions. Average Ei based on economic, mass and digestibility allocation for ‘baseline versus after RB’ were 1.6 versus 1.1, 1.8 versus 1.2 and 1.7 versus 1.2 kg CO2-equivalent/kg fat and protein-corrected milk in cows and 2.3 versus 1.5, 2.5 versus 1.6 and 2.4 versus 1.5 kg CO2-equivalent/kg fat and protein-corrected milk in buffaloes, respectively. Feeding-balanced rations significantly improved milk production, but reduced Ei of milk on lifetime basis by 31.2% and 34.7% in cows and buffaloes, respectively. Implementation of RB program has shown considerable potential to reduce GHG emission intensity under smallholding dairy production system of India.