The dairy industry supplies dietary requirements to a majority of the population. It also contributes about 1.58 percent of the country’s total greenhouse-gas emissions. Some people suggest reducing or eliminating the industry in favor of plant production. But removal of dairy cows from the United States would reduce greenhouse-gas emissions by only 0.7 percent. Moreover it would significantly reduce the supply of essential nutrients for humans, according to a team of researchers at Virginia Polytechnic Institute and State University.
“The dairy industry does have an environmental impact, but if you look at it in the context of the entire U.S. enterprise, it’s fairly minimal,” said Robin White, an associate professor in the department of animal and poultry sciences at Virginia Tech, and a member of the research team. “Associated with that minimal impact is a substantial provision of high quality, digestible and well-balanced nutrients for human consumption.”
White was part of a team that included scientists from the U.S. Department of Agriculture’s U.S. Dairy Forage Research Center. The researchers examined different scenarios for dairy cattle, taking into account current management practices as well as cow retirement and depopulation. They evaluated both the environmental and nutritional impact of three different scenarios.
Greenhouse-gas emissions were unchanged in the herd-management scenario, in which dairy products become an export-only industry and the supply of available nutrients decrease. In that scenario the industry is similar to how it is now, but people in the United States would no longer benefit from the nutrients that dairy cows provide.
The scenario where cows lived the remainder of their lives in pastures resulted in a 12-percent reduction in emissions. But 39 nutrients declined.
The scenario where cows were depopulated resulted in a 7-percent reduction in emissions. Thirty of 39 nutrients increased for the depopulation scenario. But several essential nutrients declined.
A major factor in all of the scenarios is that land use would need to be managed after removal of cows. The impact on the industry downstream must be factored into the scenario results. A pasture that formerly was used for cattle would no longer be used for that resource. Areas used for grain and fertilizer also would change functionality.
“Land use was a focus in the animal-removal scenarios because the assumptions surrounding how to use land after removing dairy cattle greatly influenced results of the simulations,” White said. “If dairy cattle are no longer present we must consider downstream effects, such as handling of pasture and grain land previously used for producing dairy feed, disposition of byproduct feeds and sourcing fertilizer.”
Plants have been thought of as a more renewable method to obtain nutrients essential for humans. But that requires farming of the land, which also produces emissions.
A significant reason why the impact of dairy cows on the environment is minimal is because of advancements in the industry in the past 50 years, White said. For example just 21 percent of the animals, 23 percent of the foodstuffs, 35 percent of the water and 10 percent of the land were required to produce 1 billion kilograms of milk in 2007 compared to 1944.
This was an extension of previous research conducted in 2017 on the reduction of animals in U.S. agriculture and the associated impacts on nutrition and greenhouse gasses. The study was supported by Dairy Management Inc. Visit vtnews.vt.edu for more information.
Max Esterhuizen is the assistant director of communications and marketing at the Virginia Polytechnic Institute and State University-College of Agriculture and Life Sciences.
Source: madison.com
