I.J.M. De Boer, Wageningen University, Netherlands
This paper used 8 studies which had used life cycle analysis to compare diverse beef production systems. The production systems were classified by the origin of calves (dairy based system vs. traditional cow-calf system) and the source of nutrients for finishing (pastures/forages vs. concentrates or a combination of both forages and concentrates). The results indicated that maintenance of the cow herd is the main contributor to all impacts (land use, energy use, and greenhouse gas emissions). In fact, data indicated that 63% of the total environmental impact was attributable to maintenance of the cow herd. This, in part, stems from the relatively low reproductive rate in cattle (as compared to other species). The environmental impacts were lower for dairy-based systems compared to traditional cow-calf systems as the majority of the impact in the dairy-based system is allocated to milk production rather than calf production. The author suggested dual-purpose (milk and meat) production systems might be one way to reduce the overall environmental impact. The data for pasture vs. concentrate finishing was less clear. The environmental impacts depend on the intensity of pasture management and the role of carbon sequestration on pasturelands. The life cycle analysis did not account for competition between humans and animals for land, which is a significant factor in determining the overall environmental impact.