Energy Consumption Modeling and Greenhouse gas Emissions in Dairy farms (Case study: Guilan Province, Iran)

The purpose of this study was to evaluate the energy consumption and greenhouse gas emissions of dairy farms in Guilan province. Data were collectedthrough questionnaires and interviews with managers of 44 dairy units. The relationship between energy inputs and milk yield for each head was studied through using Cobb-Douglas model. Data analysis revealed that a high portion of total energy consumption was allocated to the two inputs including animal feed and fossil fuels with a share of 82% and 13% respectively. Total energy inputs, productivity, specific energy and energy efficiency were calculated as 52592.81 MJ head-1, 0.25 LiterMJ-1, 7.40 MJ Liter -1 and 0.47 respectively. Regression coefficients indicated that the impact of energy inputs including human labor, fossil fuels and animal feed on the produced milk yield for each head were positive and the impact of energy inputs of electricity and agricultural machinery were negative. The results of the sensitivity analysis showed that an increase of 1 MJ in energy inputs of animal feed, fossil fuel and human labor will lead to an additional increase in milk yield for one head by 3.80, 0.084 and 0.096 liter, respectively, and an increase of 1 MJ in energy inputs of electricity and machinery, will lead to a decrease of 0.64 and 3.60 liter, respectively. Total greenhouse gas emissions of Guilan dairy farms were calculated as 1132.61 CO2eq head-1. Two inputs of diesel fuel and electricity with a share of 84% and 15% respectively had the highest share of greenhouse gas emissions.