|Rotz, Clarence - Al|
Submitted to: Sustainable Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/28/2014
Publication Date: 2/8/2014
Citation: Lizarralde, C., Picasso, V., Rotz, C.A., Cadenazzi, M., Astigarraga, L. 2014. Practices to Reduce Milk Carbon Footprint on Grazing Dairy Farms in Southern Uruguay: Case Studies.. Sustainable Agriculture Research. 3(2):1-15. Interpretive Summary: During the past decade, concerns have increased over the contribution of food production to climate change. Animal agriculture produces greenhouse gases in the form of methane from enteric fermentation, nitrous oxide from the use of nitrogenous fertilizers, methane and nitrous oxide from manure management systems and fecal deposits on pastures, and carbon dioxide through fossil fuel and electricity use. The dairy sector contributes 4% of global greenhouse gas emissions. In countries with a large livestock industry like Uruguay, agriculture contributes about 80% of their total greenhouse gas emission, mostly from pasture-based livestock production systems. Comprehensive assessment of greenhouse gas emissions from whole dairy production systems is required to measure the effectiveness of mitigation strategies. Our objective was to estimate the carbon footprint and evaluate the impact of different management practices on greenhouse gas emissions from 24 grazing dairy farms in Uruguay. Large variations in milk carbon footprint were found among the farms. High milk yield per cow, low stocking rate and a high proportion of lactating cows maintained in the herd were identified as the most promising strategies for reducing the carbon footprint of milk. The results of this study suggest that, by adopting available technologies, it is possible to reduce the milk carbon footprint of pasture-based dairy farms in Uruguay.
Technical Abstract: Carbon footprint (CF) is an increasingly relevant indicator to estimate the impact of a product on climate change. This study followed international guidelines to quantify the CF of milk produced on 24 dairy farms in Uruguay. Cows were grazed all year and supplemented with concentrate feeds. These dairy farms varied in annual milk yield per cow (5672 +/- 1245 kg FPCM), milk production (4075 +/- 1360 kg FPCM/ha), stocking rate (0.71 +/- 0.12) and percentage of concentrate in the diet (36 +/- 12 % DM) giving an average CF of 0.99 kg CO2 eq/kg FPCM (+/-10%) over all farms. Total milk production and milk yield per cow were the variables that explained most of the variation in carbon footprint. Dairy farms with similar production and feeding management were categorized into clusters. Strategies that provided the highest milk yield per cow with a low stocking rate and a high portion of lactating cows in the herd were identified as the most promising management practices for reducing greenhouse gas emissions per kg milk at the farm gate.