Mitch Stephenson

By Mitch Stephenson, Assistant Professor and Range Management Specialist


An important consideration in managing cattle on rangelands is understanding the spatial and temporal grazing patterns on rangelands. Cattle grazing behavior can be affected by a number of different variables including stocking density, number of watering locations, topography, and plant communities. Additionally, grazing behavior can be influenced by the individual preferences of an animal, the genetic capacity of each individual animal, as well as social dynamics within the herd. Understanding grazing behavior helps us better calibrate how different management strategies might affect grazing and, as a result, vegetation cover and rangeland composition.

Global positioning systems (GPS)-tracking of wildlife and domestic animals has been available to researchers for more than 25 years. Cattle fitted with GPS-tracking collars (see photo) can be monitored on a 24-hour basis for months at a time at frequent location fix frequencies. Many GPS collars also have the ability to track activity (i.e., grazing, walking, resting) of the animal with accelerometers. This is the same technology that counts the number of steps a human may take with a Fitbit or Apple watch. Figure 1 highlights the daily grazing time budget of cattle at the Gudmundsen Sandhills Lab.

Tracking with GPS collars can be used to address wide variety of research questions. Current research is seeking to better understand individual differences in grazing patterns of cattle on Sandhills rangelands. This will help us 1) better identify variables that could be used to select cattle (e.g., daily distance traveled), 2) identify consistent patterns in grazing (e.g., where cattle are grazing at different times of the year), and 3) provide insight into what variables influence grazing behavior the most (e.g., topography, time within pasture, etc.).

We are also interested in better understanding relationships between mother cows and calves. With GPS tracking we can determine how often a calf is with its mother, how often a calf nurses, and how often a calf is grazing. Understanding these types of relationships can help us to determine the role of the mother cow in the nutrition and learning of the calf.

The cost of GPS-tracking collars has typically been prohibitive (several thousand dollars per collar) to deploy collars on a large number of animals. However, costs have become more reasonable in the last several years (a few hundred dollars). As the costs come down there may be more practical applications that could be used commercially. Currently, there are options that can be utilized by producers to keep track of their livestock. While these options may not be practical for every animal of livestock operation, there may be value in knowing where certain animals are at from the convenience of a cell phone.

In the future, real-time monitoring of livestock behavior and well-being of cattle on extensive rangelands may provide added opportunities to improve grazing distribution, target graze on specific areas, identify cattle to cull or keep, or quickly asses health. GPS-tracking technology provides another layer of understanding to the research we collect at GSL and helps us to better integrate new technologies with established management practices in the Sandhills. 

Figure 1. Percent of time cattle were grazing at different hours of the day.

grazing chart