Sheep to the Rescue

Graduate student Aaron Kersh researches the benefits of grazing sheep on land impacted by deadly larkspur.

By Micaela Myers

As we gaze across the open rangeland in Wyoming, most of us may see nothing but rugged nature. However, cattle ranchers are well aware of the dangers their cattle will face, including from poisonous plants such as larkspur. Consuming even a small amount of larkspur can be fatal.

It’s a problem to which graduate student Aaron Kersh has dedicated his research. Growing up in Cheyenne, Kersh knew he’d attend the University of Wyoming, just as his parents did. After earning his undergraduate degree in rangeland management in 2021, he stayed on to pursue a master’s degree in animal science. 

Sheep have four to six times the tolerance of larkspur that cattle have. Kersh’s research involves studying sheep to see if they will consume the larkspur prior to cattle grazing.

“I like how applied my research is,” he says. “It’s helping a real-world problem for ranchers and providing opportunities for the sheep industry.”

Traditionally, ranchers have either sprayed herbicides on larkspur-impacted pastures or kept cattle off the land until the larkspur has matured and become less toxic. However, that also means keeping them off nutritious early spring grasses.

“Our aim is to see if sheep will graze the larkspur effectively and at the same time leave enough desirable forage for subsequent cattle grazing,” Kersh says.

The research takes place in collaboration with the USDA Agricultural Research Service at the High Plains Grasslands Research Station west of Cheyenne with the help of Research Leader Justin Derner. Kersh is studying various stocking densities — numbers of sheep on different sizes of pasture — as well as select breeds and ages of sheep to see what factors influence the amount of larkspur consumed. Kersh is co-advised by Extension Sheep Specialist and Associate Professor Whit Stewart and Extension Rangeland Specialist and Associate Professor Derek Scasta. All three share a passion for boosting the state’s sheep industry.

“This is a great opportunity to show people how amazing sheep are and how useful they can be,” Kersh says. “Their diet selection is different than cattle, so a lot of times when they’re grazed with cattle, they can enhance rangelands and improve rangeland health.” Sheep are showing promise with some invasive plants as well.

“We want to showcase the importance of sheep in our livestock industry,” Kersh says.

In addition to sheep, Kersh has a passion for managing America’s grasslands in a wholistic way. After graduation this spring, he plans to apply for work in this field with a number of prominent organizations. Kersh says, “My goal is to stay in grazing, rangeland management and conservation.”

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