110 Evaluation of net protein contribution and methane production from beef production as the duration of confinement increases in the cow-calf sector.

Abstract

Intensification of cow-calf production potentially increases the sustainability of beef production. Intensification’s reliance on grain may decrease the upcycling of feed protein into high-quality beef while decreasing the methane production. A previously described model was used to evaluate the effect of cow-calf intensification on two indicators of beef’s sustainability. Four scenarios were modeled based on a 1,000 cow herd: conventional cow-calf production system (0M), cows in confinement for 4 mo (4M), 8 mo (8M), or year-round (12M). No changes were made to either the stocker or the feedlot segments of the beef value chain. Net protein contribution was calculated by multiplying the ratio of human-edible protein (HeP) in the beef produced to HeP fed by the protein quality ratio. Methane was estimated based on proportion of forage in diet and total methane production was reported per kg HeP. In the cow-calf sector, HeP conversion efficiency (HePCE) decreased from 2,871.00 to 0.50 and methane production decreased from 4.19 to 1.69 kg per kg HeP as intensification increased from 0M to 12M. Decreased HePCE resulted in NPC values of 8,736, 6.51, 2.92, and 1.72 for 0M, 4M, 8M, and 12M, respectively. Protein quality ratio of the entire beef value chain increased from 3.16 to 3.34 with intensification, while HePCE decreased from 1.72 to 0.60 as length of intensification increased from 0M to 12M. Overall, NPC was 5.43, 3.75, 2.72 and 1.35 for 0M, 4M, 8M and 12M, respectively. Methane production decreased in the cow-calf sector from 4.19 to 1.69 kg of methane/kg of HeP from 0M to 12M. Across the entire beef value chain the confinement of cows for 12 months decreased methane from 2.69 to 1.35 kg/kg of HeP (0M and 12M, respectfully). Intensification of the cow-calf sector decreases total methane production and while positively contributing to NPC.