Methane Emissions in Dairy Cattle in Dependency of Rural-Urban Gradients
Ana Pinto1, Tong Yin1, Marion Reichenbach2, Raghavendra Bhatta3, Eva Schlecht2, Sven König1
1Justus-Liebig-University Giessen, Inst. of Animal Breeding and Genetics, Germany
Greenhouse gas (GHG) emissions from livestock farming have being criticised for being a main contributor to climate change. Methane (CH4) is one of the most important GHGs in dairy farming as it is 25 times more potent than carbon dioxide. Different strategies (nutrition, genetic, management) have been researched to decrease this emission. The aim of the present study was to assess the environmental impact on dairy cattle CH4 emissions, individually recorded using a mobile laser methane detector (LMD). CH4 emissions were measured along the rural-urban gradient of the rising megacity of Bengaluru, in the south of India, from June 2017 to April 2018. A simplified survey stratification index (SSI) was calculated based on building density and distance to the city centre. According to this index, three districts were defined, urban (SSI < 0.3), mixed (0.3 – 0.5) and rural (SSI > 0.5). Individual overall CH4 mean, CH4 eructation and CH4 respiration were calculated based on 2-minutes CH4 emissions from 452 cows. The basic statistical model considered fixed effects of lactation number, days in milk, breed, fasting duration prior CH4 measurement, and temperature humidity index. Random effects were cow, farm, and residual. Effect of location, SSI, access to pasture, and milk yield group were tested stepwise. For the overall mean and respiration CH4, cows from urban areas responded stronger than cows from mixed and rural areas. Cows kept on pasture emitted less CH4 than cows mainly or only kept in indoor systems. Highly productive cows had a significantly higher CH4 output (overall mean, respiration and eructation) compared to cows with medium productivity. Hence, a mixture of cow associated factors and social-ecological descriptors contribute to individual CH4 output, and in further consequence, to resource efficiency. In a next step, we will consider genetic aspects, in order to infer genotype by social-ecological interactions.
Keywords: Dairy cattle, methane emission, rural-urban farms, survey stratification index
Contact Address: Ana Pinto, Justus-Liebig-University Giessen, Inst. of Animal Breeding and Genetics, Ludwigstr. 21b, 35390 Giessen, Germany, e-mail: ana.pinto-garciaagrar.uni-giessen.de