Thirty years of improving the environmental impact of beef production
Is beef production today more efficient now than it was in the past? Have the environmental impacts of producing beef improved over the years? These questions were answered by Dr.
J.L. Capper, assistant professor of Animal Science at Washington State University, who compared the environmental impact of modern beef production (2007) and beef production in 1977. Using variables, including feedstuffs, water, land, and energy usage, changes in the animal itself, and wasted outputs, feed, energy, greenhouse gas emissions, Capper calculated that modern beef production utilizes considerably fewer resources than the equivalent 1977 system to produce one pound of beef.
Capper describes that the beef industry is broken down into several segments and most cattle go through at least two segments prior to harvest. Typically, cattle start out in a cow/calf operation, which is a pasturebased system where calves are born and raised until weaning at approximately 205 days of age. Calves may then go to a stocker/backgrounder stage, where they are grown with moderate rates of gain on pasture or in pens fed harvested forages until they reach appropriate body weights to enter the feedlot. In feedlots, cattle are fed highenergy diets to achieve fast, efficient gains until they reach finish weights and are shipped to harvest. Capper reported that in 1977, cattle always went through the stocker stage. However, in 2007, depending on weaning weight, sometimes the stocker stage was skipped. This helps to save time, money and resources when preparing the cattle to meet a certain body weight (avg. slaughter = 1,340 lb in 2007 vs. 1,031 lb in 1977). It was estimated that 16.5 percent of calves entered the feedlot directly at weaning in 2007. In addition, cattle were, on average, 123 days older at slaughter in 1977 than 2007 (608 vs. 485 days).
By improving production efficiency, a reduction in the environmental impact is achieved by a dilution of maintenance energy requirements. For the beef industry, this does not occur daily on an individual basis, but across individual animals over time and, on average, across the whole industry. The energy requirements for growing steers were 14,100 calories per day in 1977 and 20,300 calories per day in 2007. However, because of the shorter days to harvest in 2007, only 27,000 calories were required to produce one pound of beef in 2007 compared to 30,593 calories in 1977. Combined with the heavier carcass weights of modern cattle, in 2007 the U.S. produced almost 2.9 million more pounds of beef while harvesting 825,000 fewer cattle than 1977.
Each segment of production and stage of production requires different inputs of energy, feed, land and water. Figure 1 compares resources required to produce one pound of beef in 2007 compared to 1977.
Despite the fact that re sources required are only 66-86 percent of what they were in 1977, the amount of beef per animal is increased 128 percent. In addition, improvements in efficiency of nutrient and energy use have resulted in less manure production and greenhouse gas emissions (Figure 2).
According to Capper’s analysis, beef production in the U.S. had less environmental impact in 2007 than it did in 1977. Operations have become more efficient with new technologies, improvements in the cattle genetics, and across associated industries. All aspects of beef production have contributed to the reduction of environmental impact. In the future, further advances as a result of research will continue to improve the environmental impact of beef production. To read the complete report, visit the Journal of Animal Science online. — Brittany Wait, South Dakota State University