Grazing Behavior, Forage Quality, and Intake Rates of Livestock Grazing Pastures Occupied by Prairie Dogs

Abstract Prairie dogs can reduce the carrying capacity on rangelands by up to 50% through direct consumption of vegetation and by clipping plants. Studies have shown that forage quality and digestibility are greater on prairie dog towns than off town; however, research is lacking that quantifies rates of forage and nutrition intake by cattle. In 2012−2016, a study was conducted in South Dakota to evaluate livestock grazing behavior, diet quality, and forage intake on three plant communities in pastures occupied by prairie dogs. Plant communities studied were grass dominated on-town sites (PDOG-GRASS), forb dominated on-town sites (PDOG-FORB), and grass dominated off-town sites (NO-PDOG). Three pastures with varying levels of prairie dog occupation (0%, 20%, and 40%) were studied. Each pasture was grazed by a herd of yearling steers, a subset of which were fitted with Global Positioning System (GPS) collars. Daily time spent grazing was estimated for each plant community. Forage quality and intake were estimated using ruminally fistulated steers that were allowed to graze in 30-min increments within each plant community for June, July, and August of each year. Rumen samples were weighed and analyzed for forage quality. Intake was calculated as the rate of organic matter per minute and multiplied by average grazing time based on GPS collar data. Livestock grazing preference decreased linearly (P