Cattle grazing tracked as range management tool

The Fall Grassland Seminar Series hosted by the University of Nebraska-Lincoln (UNL) Center for Grassland Studies hosted a webinar on tracking cattle grazing with GPS and diet selection metrics. Range Management Specialist Dr. Mitch Stephenson from the UNL Panhandle Research and Extension Center in Scottsbluff, Neb. led the discussion. 

Stephenson starts by explaining plant growth is dynamic and grazing livestock behavior tends to be dynamic as well, both based on a multitude of variables. 

Transition with technology

“A 1938 study visually observed cattle grazing behavior at half-hour intervals over a 24-hour period in the Sandhills,” says Stephenson. “This study found cattle graze 11 to 12 hours a day and rest 12 to 13 hours a day.” 

Since this study, tracking cattle movement has dramatically progressed with new technology for cattle research, comparable to a Fitbit or an Apple Watch. GPS devices with accelerometers can be used to determine time spent grazing, resting and nursing, says Stephenson. 

“GPS technology can almost continuously track cattle movement in one second to 10-minute intervals, for anywhere between three weeks and three or more months,” he adds. 

The units, previously costing thousands of dollars, are much more affordable now, decreasing into the hundred-dollar range. GPS ear tags are even available as an option, making precision agriculture for livestock more available to commercial producers. 

Based on a continuous, automatic and real-time monitoring and control of production and reproduction, precision livestock management is gathering more data to use for decision making.

With rangelands mostly being extensive systems, Stephenson focuses on resource distribution, forage quality and distribution and things producers can’t manage such as weather, wild herbivores, predators and topography. 

Where cattle are grazing

“One of the questions we’ve been looking to answer is where cattle are grazing,” he explains. “We can look at vegetation areas at the landscape or pasture scale, down to the plant community and individual plants the animal consumes.”

A recent study Stephenson conducted tried to predict grazing utilization relative to cattle grazing behavior. Their first step was to develop a topography index of the site using a digital elevation model to classify the upper, middle and lower parts of the landscape, which were labeled as lowlands, flat plains, open slopes and uplands. 

“We were able to add resource selection probability to identify areas of the pasture receiving higher grazing pressure under different grazing strategies,” shares Stephenson. “We saw topographic influence on grazing utilization, which gave us some ideas in terms of management as far as where our cattle are more likely to over-utilize certain areas and plant species.” 

In predicting cattle grazing locations, larger pastures tend to have less even grazing and distribution, while smaller pastures saw more uniform use, says Stephenson. Grazing behavior influences vegetation composition, plant structure and health and can influence multiple ecosystem structures within the same pasture. 

What cattle are grazing

The second question Stephenson has been working to answer is what cattle are eating. Using fecal DNA and GPS monitors, researchers have been able to tackle challenges as tough as cheatgrass management. 

“Targeted cheatgrass grazing has shown to be effective at reducing cheatgrass seed production, biomass and fire risk,” notes Stephenson. “Although, the risk of grazing native perennials early in the grown season if cattle aren’t grazing the cheatgrass, will discourage perennial plant growth.” 

Using GPS collars to determine time grazing in cheatgrass-filled areas, Stephenson and his team found potential target timing for cheatgrass grazing to be used as a management tool, without harming native perennial grasses. 

Stephenson concludes, “In the future, there may be opportunities for producers to use this kind of technology to get clear ideas of the plants their cattle are using and key times their cattle are using those plants.” 

Averi Hales is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.