The carbon footprint of beef production from cull cows finished on sown pastures in the savannas of the Colombian Orinoquía

Abstract

Neotropical savannas of the Colombian Orinoquia are largely dedicated to year-round beef production. There is evidence of sustainable animal production in this savanna environment, but little is known of the links among animal lifetime performance, greenhouse gas emissions, and soil organic carbon (SOC) accumulation at the system level. The main objective of this study was to estimate C footprint of beef production from Brahman (Bos indicus) cull cows finished on contrasting C4-grass-based pastures in the Orinoco basin. Long-term individual variations of liveweights and reproductive performance were used in an Excel® dynamic model to estimate dry matter intake, methane (CH4) emissions and carcass traits, and C footprint at the farm gate. Values from the developed database were computed for cows born and raised on the savanna, bred on Brachiaria decumbens, and later finished on B. humidicola [Scenario (SCE) 1, SCE 2]; B. decumbens (SCE 3); Andropogon gayanus + Melinis minutiflora + Stylosanthes capitata (SCE 4); and A. gayanus + S. capitata (SCE 5) pastures. We estimated C footprints of SCE 1, SCE 3, and SCE 5 using published values of the rates of emission of CH4 and nitrous oxide from the soil, feces, and urine; and accumulation of SOC in soil during the fattening period. The majority of the estimated overall C footprint values at the system level were negative due to expected net SOC accumulation during the fattening period. Depending on the expected quality of management, systems ranged from near equilibrium in C balance to net increases in SOC accumulation.