A case study on carbon footprint evaluation of cow milk production via life cycle assessment in Taiwan

• Main Authors: Chi, Yang-Chu, 紀泱竹
• Other Authors: Chang, Hsiu-Luan
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/s8ry62

碩士 === 國立屏東科技大學 === 動物科學與畜產系所 === 105 === Agriculture production contributes 10–12% of overall global emissions. Of this, livestock production is recognized as the major contributor of global agricultural greenhouse gas (GHG) emissions, which accounts for around 80%. According to the International Organization for Standardization (ISO), life cycle assessment (LCA) is defined as the compilation and evaluation of the inputs, outputs, and potential environmental impact of a product system in its life cycle. Life cycle assessment is a promising tool for benchmarking carbon footprint among different production systems. This approach could also be used as a mitigation indicator in the enforcement of political decision. Therefore, the purposes of this study were evaluate the carbon footprint of dairy production in dairy farm with quantification of GHG intensity in milk production, and identified the various sources of emissions and the corresponding contributions, as well as the possible mitigations options, and thus to establish the optimum management strategies for greenhouse gas mitigation in dairy industry. In experiment 1, life cycle assessment software SimaPro was used to evaluate the dairy farm with cradle-to-farm gate boundary, which included feed production, cow milk production, and manure treatment. However, the management information, including herd size, milk yield, body weight, feed intake, water, power and diesel fuel consumption, were also collected and combined with emission factors in estimation of carbon footprint. In experiment 2, GHG emission of 100% fresh milk in life cycle, starting from preparation of raw materials, manufacture, distribution retail, consumer use, until disposal/recycling stage, was evaluated. Results indicated that the carbon footprint of raw milk evaluated by life cycle assessment were 1.51 (1.15–2.07) kg CO2 equivalent during 2014 and 2016. There was a significant (P < 0.05) lower emission in 2016 compared to those of 2014 and 2015, which might be due to higher average daily milk yield per head in 2016. Also, more carbon footprint per kg raw milk was observed during July and September of years studied, which was consistent with the fact of low milk yield and high power consumption due to heat stress during hot season. In addition, the association between milk yield and CO2e emission per unit milk production implied that milk efficiency was the key issue of carbon footprint due to milk production. Similarly results was found when comparison was made between seasons, i.e., more carbon footprint produced per kg raw milk in hot season than that in cool season (P < 0.05). The reason was due to the low milking efficiency and more power consumption required in hot season. The estimate of carbon footprint for 100% fresh milk product (930 mL/bottle) via life cycle assessment was 2.309 kg CO2e. Raw materials processing stage was the predominant source of GHG emissions, which accounted for 91.51% of total emission. In conclusion, the carbon footprint evaluation of cow milk production via life cycle assessment showed GHG emissions produced by dairy farms could be significantly reduced by increasing milk production and herd production efficiency, and reducing enteric CH4 of lactating cow. Therefore, one can expect that CO2e emission per unit milk production might be effectively reduced through the mitigation strategies, such as herd management and energy consumption.