Greenhouse Gas Emissions of Beef Cow-Calf Grazing Systems in Uruguay

Gonzalo Becona,Laura Astigarraga,Valentin D Picasso

doi:10.5539/sar.v3n2p89

Gonzalo Becona, Laura Astigarraga + Show 1 more

Open Access

https://doi.org/10.5539/sar.v3n2p89

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Abstract

Evaluating greenhouse gas (GHG) emissions at farm level is an important tool to mitigate climate change. Livestock account for 80% of the total GHG emissions in Uruguay, and beef cow-calf systems are possibly the largest contributors. In cow-calf grazing systems, optimizing forage allowance and grazing intensity may increase pasture productivity, reproductive performance, beef productivity, and possibly reduce GHG emissions. This study estimated GHG emissions per kg of live weight gain (LWG) and per hectare from 20 cow-calf systems in Uruguay, with different management practices. The GHG emissions were on average 20.8 kg CO2-e.kg LWG-1, ranging from 11.4 to 32.2. Beef productivity and reproductive efficiency were the main determinants of GHG emissions. Five farm clusters were identified with different productive and environmental efficiency by numerical classification of relevant variables. Improving grazing efficiency by optimizing the stocking rate and forage production can increase beef productivity by 22% and reduce GHG emissions per kg LWG by 28% compared to “low performance” management. Further improvements in reproductive efficiency can increase productivity by 41% and reduce GHG emissions per kg LWG by 23%, resulting in a “carbon smart” strategy. However, the most intensified farms with highest stocking rate and beef productivity, did not reduce GHG emissions per kg LWG, while increased GHG emissions per ha compared to the carbon smart. This analysis showed that it is possible to simultaneously reduce carbon footprint per kg and per ha, by optimizing grazing management. This study demonstrated that there is high potential to reduce cow-calf GHG emissions through improved grazing management.

Highlights

International concerns about climate change and greenhouse gas (GHG) emissions have grown in the last decades (Intergovernmental Panel on Climate Change [IPCC], 2013)
The livestock sector accounts for 14.5% of the global GHG emissions, and close to half of this is due to the beef sector which accounts for 6% of the global GHG emissions (Gerber et al, 2013)
A research challenge that still remains is how to analyze and integrate information from variables managed at the field or patch level, technological variables managed at the farm level (e.g., % of area in improved pastures) and farm performance variables

Summary

Introduction

International concerns about climate change and greenhouse gas (GHG) emissions have grown in the last decades (Intergovernmental Panel on Climate Change [IPCC], 2013). There is a high potential for reducing GHG emissions, and thereby the carbon footprint, in beef systems worldwide. Carbon footprint is the sum of greenhouse gas emissions throughout the life cycle of a product or a system. It is usually expressed from the standpoint of the consumer, as kg of CO2 equivalent per unit of a product (De Vries & de Boer, 2010). Adequate estimation and analyses of carbon footprint are crucial for identifying opportunities to reduce GHG emissions, especially in countries with large livestock production such as Uruguay, Brazil, New Zealand, or Canada (Modernel, Astigarraga, & Picasso, 2013; Ruviaro, de Léis, Lampert, Barcellos, & Dewes, 2014; Beauchemin, Janzen, Little, McAllister, & McGinn, 2010)

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