Annual Review of Animal Biosciences - Volume 1, 2013

The global livestock industry is charged with providing sufficient animal source foods to supply the global population while improving the environmental sustainability of animal production. Improved productivity within dairy and beef systems has demonstrably reduced resource use and greenhouse gas emissions per unit of food over the past century through the dilution of maintenance effect. Further environmental mitigation effects have been gained through the current use of technologies and practices that enhance milk yield or growth in ruminants; however, the social acceptability of continued intensification and use of productivity-enhancing technologies is subject to debate. As the environmental impact of food production continues to be a significant issue for all stakeholders within the field, further research is needed to ensure that comparisons among foods are made based on both environmental impact and nutritive value to truly assess the sustainability of ruminant products.

When a stunning method is being evaluated, it is essential that the animal-handling and restraint methods that are used with it are also examined. This makes it possible to determine the effect of the entire system on animal welfare. Cattle, pigs, and sheep will move easily through the races at a slaughter plant if visual distractions such as reflections on shiny metal, dangling chains, moving equipment, or people up ahead are removed. The most important scientific research on captive bolt, CO2, and electrical stunning methods is reviewed. A common mistake made by people evaluating insensibility is to misinterpret reflexive leg kicks as a sign of return to sensibility. When religious slaughter is being evaluated, the variable of how the animal is restrained must be separated from the variable of slaughter without stunning. Slaughter can be done with a high level of animal welfare.