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Stam emphasizes knowledge of supply and demand in developing grazing plans

by Wyoming Livestock Roundup

“When we think about grazing plans, we have to think about the supply and demand of our pastures,” says University of Wyoming (UW) Northwest Region Range Extension Specialist Barton Stam.

Stam explains the supply and demand of a pasture relates to the supply of usable forage and the demand of the livestock grazing it. 

Determining supply 

“UW has a variety of tools ranchers can use online to help figure out the pounds of forage in a particular pasture,” Stam notes. “The old-school methods such as throwing the hoop or measuring height just aren’t feasible in range environments.” 

Stam notes while more traditional methods have a place with smaller and more uniform pastures, they aren’t always the best with range environments because there would need to be such a large sample to get a statistically accurate estimate. 

“The online tools aren’t reinventing the wheel,” says Stam. “We are applying old math and formulas and making it easy to use for everyday producers.” 

“The most popular tool on the website uses past use to determine pounds of forage per acre,” Stam explains. “For this calculator, producers need specific data for the number of head grazed, average weight per head, days in pasture, acres in pasture and an estimate of utilization.”

Stam notes ranchers more often overestimate their utilization and believes this is in an effort to give a conservative estimate. 

“For producers with cow/calf pairs trying to use this calculator, remember, if the calf is still very young and relying on milk more than grass, to just add pounds to the mother and not add another head,” he explains. “So, if we have a cow with a moderate size calf, add 200 pounds to her weight to take the calf into consideration.” 

He adds, “This method will also work for sheep nursing lambs.”

Stam notes the tool may not be suited for everyone but is the most popular. 

He recommends ranchers visit to explore other tools to use to determine forage supply.

Determining demand 

“Determining demand is much simpler in theory,” Stam says. “This estimate will help determine how much forage livestock needs.” 

“To determine demand, we need to consider the weight of the cows and at what point in the reproductive cycle they are in,” he says. 

Stam notes cattle in different phases of reproduction have different needs. Those later in their pregnancy or nursing young calves have much greater needs than those early on in pregnancy or open.

“Once we determine our demand, we need to look at our pastures and figure out how to achieve this need,” says Stam. “From here, we can make adjustments to our management plan.” 

Stam notes if a rancher feels as though they need to supplement their stock in some way, there are also tools to determine the economic return on these investments. These tools can also be found at

“One of the contributors to the ranch tools website is an economist, which was super helpful,” Stam notes. “These tools allow ranchers to determine if additions such as mineral, water and fencing are economically viable.”

Improving stocking rates

“Once we know the supply of our pastures and demand of our livestock, we can talk about stocking rates,” says Stam. “There are a lot of misconceptions surrounding how we can improve stocking rates.” 

“The first thing we need to clear up is the difference between resting a pasture and deferment,” Stam notes. “In my opinion, there are very few situations where actual rest is needed.” 

Stam explains the professional range management community defines rest as a full 12 months of no grazing. In comparison, deferment refers to deferring grazing to a later time within a 12-month period. 

“More often than not, deferment will work just fine in improving pasture health and ultimately stocking rate,” Stam comments. 

“Close the gates,” Stam stresses. “Improving usage of the land can really be this simple.” 

He also notes the placement of attractants such as mineral and water should be places where cows don’t normally congregate. 

“Place water and mineral somewhere away from ideal grasses and locations to get the cows to spread out and better utilize the whole pasture,” Stam says. 

Stam presented on grazing management at the annual Fremont County Farm and Ranch Days in Riverton. The two-day event is held annually in February.

Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to

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