Beef cattle are not a major factor in global warming, a new U.S. Department of Agriculture-led study says.
"We found that the greenhouse gas emissions in our analysis were not all that different from what other credible studies had shown and were not a significant contributor to long-term global warming," said Alab Rotz, an agricultural engineer with USDA's Agricultural Research Service.
Greenhouse gas emissions - gaseous compounds in the atmosphere that absorb infrared radiation, thereby trapping and holding heat in the atmosphere - are linked to global warming.
But the study found that "beef cattle production accounted for 3.3 percent of all U.S. Greenhouse gas emissions. (By comparison, transportation and electricity generation together made up 56 percent of the total in 2016 and agriculture in general 9 percent)."
The study, partially funded by the National Cattlemen's Beef Association, was conducted by scientists from the ARS, universities and the cattlemen's group. Its goal is to "establish baseline measures that the U.S. beef industry can use to explore ways of reducing its environmental footprint and improve sustainability."
The five-year study covered seven cattle-producing regions and used data from 2,270 survey responses and site visits nationwide. The diversity ensured the results weren't limited to a single region, where climate, soil, production practices and other factors can differ from other parts of the country, Rotz said. He's with the ARS Pasture Systems and Watershed Management Research Unit in University Park, Pa.
The research team recently published the first of two sets of results. Among the results to emerge so far:
• Fossil energy (for example, fuel) use in cattle production accounted for less than 1 percent of the total consumed nationally.
• Cattle only consumed 2.6 pounds of grain per pound of beef cut weight (or, butchered carcass weight), which was comparable to pork and poultry.
• Beef operations in the Northwest and Southern Plains had the highest total water use (60 percent combined) of the seven regions analyzed. Irrigating crops to produce feed for cattle accounted for 96 percent of total water use across all the regions.
But two areas for potential improvement were identified by the research: water use and reactive nitrogen loss.
Water use is increased in the western U.S., where cattle production is concentrated. And reactive nitrogen loss, mainly in the form of ammonia from cattle waste, can lead to smog, acid rain and algal bloom, the report said.
Nitrogen is a key component in plant and animal growth. Reactive nitrogen refers to various nitrogen compounds that support growth directly or indirectly.