Over 14 years, the researchers collected more than 21,000 fecal samples from grasslands and pastureland in various U.S. regions. The samples were analyzed for their nutritional content at the Texas A&M University Grazingland Animal Nutrition Lab. The lab compared the amount of crude protein and digestible organic matter retained by cattle among the regions.
Joseph Craine, a research assistant professor at Kansas State University's Division of Biology and the principal investigator for the project, says the pattern of forage quality observed across the regions suggests that a warmer climate would limit protein availability to grazing animals.
Cattle now get more than 80 percent of their energy from rangeland, pastureland and other sources of roughage. Craine said that increased temperatures in the future may limit plant protein concentrations, so ranchers may have to start thinking now about how to manage their herds differently or provide supplemental protein.
"The trickle-down to the average person is essentially thinking ahead of time of what the consequences are going to be for the climate change scenarios that we are says at and how ranchers are going to change management processes," said Craine.
The study results are published in the journal Global Change Biology.