The most common beef background-finishing systems in the region studied are five different combinations of rangelands (RL) and seeded pastures (SP) in the rearing phase (where animal weight increases from 150 to 350 kg) and rangelands, seeded pastures and feedlots (FL) in the finishing phase (where the animals go from being around 350 kg to a slaughter weight of 500 kg). In these systems, the time to reach the final weight decreases from 28 months for RL–RL to up to 13 months for SP–FL thanks to external inputs and cropping activities. Greenhouse gas emissions per kilogram of live weight are lower as livestock production intensifies, with the lowest values being seen in SP–FL.

On the other hand, fossil fuel energy consumption and grazing soil erosion rates increase as the system relies more on inputs and on cropping activities to produce grain (SP–FL). Regarding nutrient balances, we found that rangeland systems (RL–RL) produced the smallest amount of nitrogen and phosphorus, while the other systems had surpluses of nutrients and therefore a higher risk of water contamination. Rangeland systems do not use pesticides so the relative risk of contamination is zero. All other systems use pesticides and the risk increases as we move to systems with higher use, and cropping activities.

Our results question the evaluation of sustainability by only one indicator. Although systems with more intensive use of inputs enhance productivity and perform better in terms of greenhouse gas emissions per unit of live weight gain, they perform worse in terms of energy consumption, soil erosion and surpluses of phosphorus and nitrogen in the environment, as well as having greater risk of contamination by pesticides.

We expect that our results will make policy-makers aware of these trade-offs and call for further research to understand the link between the environment and meat production.

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