optimization of energy use of dairy farms by dea approach (case stude: mazandaran province)

the aim of this study wasthe use of data envelopment analysis for determined the energy efficiency and find the optimum energy consumption in dairy farms of mazandaran province of iran. in this study have been used from two approaches constant returns to scale and variable returns to scale model of data envelopment analysis for determined the degrees of technical efficiency, pure technical efficiency and scale efficiency. moreover, the effect of optimum energy consumption on greenhouse gas emissions has been studied and the total amount of greenhouse gas emissions. the results showed that from total number of dairy farms 42.55% and 53.19% were efficient based on constant returns to scale and variable returns to scale model, respectively.accordingly, the average score of technical, pure technical and scale efficiencies of farmers werecalculated 0.9, 0.94 and 0.953, respectively. the total optimum energy required wasestimated 129932 (mj cow-1). energy saving target ratio for dairy farms was calculated as 12%.according to results feed intake had the highest share (85.44%) from total saving energy, followed by fossil fuels (11.19%). the total greenhouse gas emissions was calculated 5393 (kgco2eq. cow-1year-1) in dairy farms that this amount can be reduced to 4738 (kgco2eq. cow-1 year-1) with optimum energy consumption. the enteric fermentation had the highest potential to reduction of total ghg emissions with 47% that has a direct connection to the amount of feed intake.