Management of cheatgrass (Bromus Tectorum L.) fuel loads with strategic fall cattle grazing

Strategic fall cattle grazing to this point has been shown in demonstration ranches to provide opportunities for improved cheatgrass management, increased perennial grass production  in cheatgrass infested areas, improved body condition and typical rates of grain for cattle, and reductions of thatch leading to reduced cheatgrass recovery after grazing (Schmelzer et al 2014).  In October and November of 2014, year one of a planned three year project was initiated at a production scale (with 6,000 acres and 800 cows). The study was conducted at the TS Ranch near Dunphy, Nevada. While the main objective of the study focuses on cheatgrass management and reduction, there are other aspects of the grazing experiment that are needed to assure that the approach to cheatgrass management is environmentally and economically beneficial. Collaborators include Tony Svejcar, Chad Boyd, and Kirk Davies with the USDA-ARS at the Eastern Oregon Agricultural Research Center.

Objective

Evaluation of the effectiveness of fall cattle grazing and the strategic placement of liquid protein supplement to reduce standing and thatch biomass fuels within cheatgrass-infested areas is the overall objective of the research. There are important side aspects of the experiment that are critical to scientifically establishing the benefits of this management approach to infested cheatgrass areas.  These will be investigated, as well, in this research project and are:

• Establishing the importance of the thatch to regrowth of cheatgrass after all standing and thatch has been removed (from demonstrations we have observed reduced stands of cheatgrass after it has been removed by grazing, likely due to the elimination of thatch as a growing medium),
• Verifying by careful measurement the rates of gain and condition of the cattle that are fall grazing the cheatgrass,
• Understanding any soil movement that is associated with the fall grazing of cheatgrass,
• Economic analysis of the fall grazing experiment to verify the observed benefits of fall grazing.

The research area has been staked off to permit scientific comparisons that will support the above research 0bjectives aad allow careful evaluations in each case.

Study Area

• TS Ranch near Dunphy, Nev.
• Mack Farm Pasture
  • 6,000 acres – 60 % “go-back” farmland infested with cheatgrass and 40% cheatgrass/greasewood range
• Eight hundred mature cows within the second trimester of pregnancy were placed on the study pasture shortly after their calves were weaned
• Cattle grazed on the Mack Farm Pasture from 10/8/2014 to 11/15/2014
• Original plots in the area were staked to provide controls for the grazing experiments and will be maintained throughout the experiment,
• Samples from these controls will  be used to conduct the related experiments throughout the experiment.

Methods

• Eight liquid protein supplement tanks (32 % crude protein, Bovatec) were moved weekly to attract cattle grazing to strategic locations along a 2.5 mile fuel break area (Fig. 1).
• Cheatgrass biomass estimates collected along the fire break before cattle were turned out on the pasture and at the conclusion of the study.
• Four sets of grazing exclosures (set at ~1 kilometer intervals away from water) were constructed to compare yearly differences between grazed and non-grazed areas (Fig. 1).
• Samples will be taken from the grazing enclosures for the experiments about regeneration of cheatgrass on previously grazed land, understanding soil movement and economic analysis.
• Eight randomly selected cows were fitted with global positioning system (GPS) collars to evaluate cattle movements within the pasture.
• Twenty-five randomly selected cows were marked with ear tags and evaluated for body condition score (BCS) before and after the grazing treatment to determine the effect of grazing cheatgrass in the fall on cattle performance.

Preliminary Results

• Supplement intake = 2.2 ± 0.07 lbs ? cow^-1 ? d^-1
• Mean cheatgrass standing biomass along the fire break:
  • Initiation of the study (10/8/2014) = 471 ± 35 lbs ? ac^-1 SE
  • Conclusion of the study (11/15/2013) = 85 ± 10 lbs ? ac^-1 SE.

• GPS collared cattle consistently used areas greater than 2.5 miles from water and areas surrounding the supplement link tanks
• Mean body condition score:
  • Initiation of the study (10/8/2014) = 5.09 ± 0.1 SE
  • Conclusion of the study (11/15/2013) = 5.13 ± 0.1 SE
• Samples for these longer term research projects are being taken.

Discussion

• Preliminary results at a larger production scale at the TS Ranch support data collected by Schmelzer et al. (2014).
• Fall cattle grazing was effective at reducing cheatgrass standing biomass
  • Potential to reduce the frequency, intensity, or extent of wildfires in the Great Basin (Strand et al. 2014).
• Cattle maintained body condition while grazing on dormant cheatgrass with liquid protein supplements
• More research at the TS Ranch is needed to determine the longer term effectiveness of fall cattle grazing to reduce the cover, seed bank density, and amount of cheatgrass, but preliminary results suggest that fall cattle grazing may provide an important tool for managing cheatgrass fuel loads on Great Basin, sagebrush steppe rangelands.

Management Implications

• Fall cattle grazing to reduce residual (thatch) and standing cheatgrass biomass may be especially important in areas with high cheatgrass production.
• Grazing plans and National Environmental Policy Act (NEPA) documents on federal lands should include options for fall cattle grazing to manage fine fuel loads in areas with high amounts of cheatgrass.

Literature Cited

• Schmelzer, L., B. Perryman, B. Bruce, B. Schultz, K. McAdoo, G. McCuin, S. Swanson, J. Wilker, and K. Conley. 2014. Case Study: Reducing cheatgrass (Bromus tectorum L.) fuel loads using fall cattle grazing. The Professional Animal Scientist 30:270-278.
• Strand, E. K., K. L. Launchbaugh, R. Limb, and L. A. Torell. 2014. Livestock grazing effects on fuel loads for wildland fire in sagebrush dominated ecosystems. Journal of Rangeland Applications 1:35-57.