Black-tailed prairie dogs can be a nuisance to livestock, competing for forage, creating an injury hazard and generating population control costs.
A long-term study by scientists at USDA’s Agriculture Research Service (ARS) found a possibility prairie dogs and cattle can coexist, as cattle weight-gain loss was less than expected in areas occupied by prairie dogs.
“Based on the findings thus far, we’ve found that prairie dogs and cattle can coexist on the same pastures, with only minor declines in cattle weight gain when prairie dogs are abundant,” said David Augustine, a research ecologist with the Center’s Rangeland Resources and Systems Research Unit.
“Under conditions of average rainfall during the growing season in shortgrass steppe, prairie dog grazing reduces the amount but enhances the quality of the forage. After measuring the biomass of forage left behind on prairie dog colonies, we found that both protein content and in vitro dry matter digestibility were enhanced. As a result, the cattle can still spend a considerable amount of their time grazing on prairie dog colonies.”
In the 12-year study published July in the Journal of Wildlife Management, Augustine, along with Justin Derner at the ARS Center for Agricultural Resources Research in Fort Collins, CO, conducted two studies to evaluate how livestock performance is affected by grazing competition with prairie dogs.
Yearling steers grazed on shortgrass prairie pastures in which prairie dogs were either controlled or were allowed to fluctuate naturally in abundance. The study found that on pasture where prairie dogs occupied 30 percent, cattle weight gain over the summer declined by 4 percent relative to pastures without prairie dogs. When prairie dog occupancy increased to 60 percent of a pasture, cattle weight gain declined by 8 percent.
Averaged over the entire 12-year study, cattle gained an average of 2.13 lbs. per steer per day (equivalent to a gain of 299 lbs. over a 140-day grazing season) where prairie dogs were controlled by rodenticide, and 2.09 lbs. per steer per day (equivalent to a gain of 293 lbs. over a 140-day grazing season).
The findings were similar to a previous study by Derner which found in pastures with a 20 percent area occupied by prairie dogs, the estimated livestock weight gain loss was $14.95 per steer, and in areas with 60 percent occupation, the loss was $37.91 per steer, or about 14 percent.
The scientists noted these results are based primarily on measurements during years with average or above-average rainfall. They are still concerned that significant impacts could occur during a drought if prairie dogs occupy a larger percentage of pastures.
“In rare occasions, we may find a high number of prairie dogs in pastures during months of low precipitation, and this combination could have a detrimental effect on the availability of forage,” Augustine noted.
Augustine and Derner emphasized that more research needs to be conducted on drought conditions and their associated costs. They also said more work needs to be done with grazing management and conservation-focused measures to manage livestock while still maintaining biodiversity. — Charles Wallace, WLJ editor
