MALAD, Idaho — May 6, 2025 — A recently published University of Idaho-led study suggests extending fall grazing of federal allotments could stymie invasive annual grasses while providing ranchers with additional forage. 

The paper “Daily Behavior and Performance for Cows Engaged in Targeted Grazing in Southeast Idaho” was published April 30 in the journal Rangelands.

Jim Sprinkle, a professor and Extension beef specialist based at U of I’s Nancy M. Cummings Research, Extension and Education Center in Salmon, was the lead author. 

The study received a special-use permit for dormant-season grazing of the U.S. Forest Service’s 2,468-acre Spring Hills allotment near Malad in both 2021 and 2022. The allotment has a composition of about 24% invasive cheatgrass, which is considered a mild infestation. The Malad area is part of a corridor extending to the state’s southeastern border where native perennial grasses remain largely intact, and land managers see potential for success with strategies to suppress invasive annual grasses. 

“It’s within that range where we could probably have some type of influence with targeted grazing to keep the landscape from becoming more infested,” Sprinkle said. 

Current federal grazing permits were written before annual grasses gained a foothold throughout Idaho. Allowing cattle to remain on allotments into the dormant season — from mid-October until snow forces cattle off — promises to target annual grasses when they are most vulnerable.

Cattle will feed on cheatgrass in the spring but abandon it in favor of native perennial grasses once the cheatgrass turns red, usually by mid-June. By mid-October, annual grasses drop their seeds, making them palatable to cattle again. Short days and cool weather later in the fall encourage cattle to eat faster, and they can efficiently chomp fine-textured annual grasses. Furthermore, cattle hooves break up cheatgrass thatch, which is important for its seed germination. 

The rancher who cooperated in the study grazed the allotment with 300 yearling heifers from April 29 through May 29 in 2021 and with 400 yearling heifers from May 2 through May 31 in 2022. He also introduced dormant season grazing with 400 nonlactating cows from Oct. 25 through Nov. 22 in 2021 and with 316 nonlactating cows from Oct. 25 through Nov. 19 in 2022. 

Sprinkle and his team made special collars with GPS devices to track livestock location and accelerometers to determine whether cattle were grazing, resting or walking. They collared 34 cows in 2021 and 36 cows in 2022. 

During 2021, rainstorms arrived before freezing weather, contributing to late-season greening. That fall, cattle spent 40% of their time grazing south-facing slopes, which were exposed to sunlight and warmth. Cattle gained weight without being fed any supplemental protein.

During 2022, the weather was dry, and satellite imagery showed the landscape did not turn green. Livestock spent just 28% of their time on south-facing slopes and the remainder of their time on north-facing slopes, which tend to be cooler and retain moisture longer. Fed no supplemental protein, the cattle lost 1.87 pounds per day on average. 

Based on the results, Sprinkle suggests using satellite imagery to determine when the lack of verdant forage necessitates feeding cattle supplemental protein, which also helps livestock better digest dry grasses. Even factoring in the cost of supplemental protein, ranchers stand to reduce feed costs by about two-thirds during dormant season grazing. 

“When conditions are such that you have a green-up, we’ll also be growing more invasive annual grasses, and we want to address that problem. So if we can put livestock out there when the climate is trying to grow more of those invasive annual grasses, we can help suppress the population and also achieve good quality gains on livestock at the same time,” Sprinkle said. “In years when forage quality is not as good and we still want to target annual grasses, we can still do that but also provide supplemental protein.”

Annual grasses start growing before native perennials and can outcompete them. Once annual grasses overtake an area, a cycle of wildfires begins, burning forage every year and excluding grazing until the annual grasses return and burn again. The area between Boise and Glenns Ferry, for example, has been overtaken by annual grasses and has had more wildfire ignitions than anywhere else in the U.S., as of 2016.

Similar dormant season grazing studies conducted in Eastern Oregon and Nevada have demonstrated that this management practice can help shift the balance back in favor of perennials and reduce wildfire fuel loads.

“You might have to supplement with protein, but you’re doing an additional service by the control you’re providing,” Sprinkle said. “I hope we see more and more of these projects happening.”

The research team also included Justin Hatch, with UI Extension in Caribou County; Sawyer Fonnesbeck, with UI Extension in Oneida County; Dan Lauritzen, with the College of Natural Resources; Cole Kempton and April Hulet, both with Brigham Young University’s Department of Plant and Wildlife Sciences; Robbert Mickelsen, with the Caribou-Targhee National Forest and Curlew National Grassland; Hans Bastian, with the U.S. Forest Service’s Westside Ranger District, Jared Simpson, with S Bar S Cattle Ranch in Malad; and Jameson Brennan, with South Dakota State University’s West River Research and Extension Center. 

Mickelsen approached the university about conducting the two-year study, which was funded with $29,000 from the U.S. Forest Service under award No. 19-PA-11046000-030. 

About the University of Idaho

The University of Idaho, home of the Vandals, is Idaho’s land-grant, national research university. From its residential campus in Moscow, U of I serves the state of Idaho through educational centers in Boise, Coeur d’Alene and Idaho Falls, nine research and Extension centers, plus Extension offices in 42 counties. Home to more than 11,000 students statewide, U of I is a leader in student-centered learning and excels at interdisciplinary research, service to businesses and communities, and in advancing diversity, citizenship and global outreach. U of I competes in the Big Sky Conference. Learn more at
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