Evaluation of net protein contribution, methane production, and net returns from beef production as duration of confinement increases in the cow-calf sector1.

Intensification of cow-calf production may provide a sustainable solution for meeting increasing beef demand in the face of diminishing resources. However, intensification with its greater reliance on cereal grains potentially decreases the upcycling of human-inedible protein into beef. A previously described model was used to evaluate cow-calf intensification on beef's ability to meet human protein requirements. Four scenarios were compared, based on a 1,000 cow herd: 1) Conventional cow-calf production system (0CON), 2) cows limit-fed in confinement for 4 mo after weaning (4CON), 3) cows limit-fed in confinement for 8 mo after breeding (8CON), or 4) cows limit-fed in confinement year-round (12CON). Changes were not made to either the stocker or feedlot segments of the beef value chain. Net protein contribution (NPC) was calculated by multiplying the ratio of human-edible protein (HeP) in beef produced to HeP in feed by the protein quality ratio. A NPC >1 indicates that the production system is positively contributing to meeting human requirements, whereas a NPC <1 indicates the sector or value chain is competing with humans for HeP. 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 2,640.83 to 0.37 while methane production decreased from 4.53 to 1.82 kg/kg HeP produced as the length of intensification increased from 0CON to 12CON. Decreased HePCE resulted in NPC values for cow-calf sector of 8,036.80, 4.93, 2.19, and 1.28 for 0CON, 4CON, 8CON, and 12CON, respectively. Protein quality ratio of the entire beef value chain increased from 3.15 to 3.33, while HePCE decreased from 0.99 to 0.39 as length of intensification increased from 0CON to 12CON. For the beef value chain, NPC was 3.11, 2.30, 1.73, and 1.31 for 0CON, 4CON, 8CON, and 12CON, respectively. Across the value chain, confinement of cows for 12 mo decreased enteric methane from 3.05 to 1.53 kg/kg HeP (0CON and 12CON, respectfully). Additionally, profitability of the cow-calf operation decreased from $249.34 to $102.16 per cow as intensification increased. Of confinement scenarios, probability of loss to an operation was least (4%) for 4CON. Feed costs increased by $260.79 per cow for 0CON when drought conditions existed (0COND). Total methane production was reduced by intensification and none of the scenarios evaluated competed with humans for HeP.