Rangeland Ecology & Management

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Effects of Grazing Pressure on Efficiency of Grazing on North American Great Plains Rangelands
Author
Smart, A. J.
Derner, J. D.
Hendrickson, J. R.
Gillen, R. L.
Dunn, B. H.
Mousel, E. M.
Johnson, P. S.
Gates, R. N.
Sedivec, K. K.
Harmoney, K. R.
Volesky, J. D.
Olsen, K. C.
Publisher
Society for Range Management
Publication Year
2010-07-01
Body

Comparisons of stocking rates across sites can be facilitated by calculating grazing pressure. We used peak standing crop and stocking rates from six studies in the North American Great Plains (Cheyenne, Wyoming; Cottonwood, South Dakota; Hays, Kansas; Nunn, Colorado; Streeter, North Dakota; and Woodward, Oklahoma) to calculate a grazing pressure index and develop relationships for harvest efficiency, utilization, grazing efficiency, and animal performance and production. Average grazing pressures for heavy, moderate, and light stocking across the study sites were 40, 24, and 14 animal unit days Mg-1, respectively. These grazing pressures resulted in average harvest efficiency values of 38%, 24%, and 14% and grazing efficiencies of 61%, 49%, and 39% for heavy, moderate, and light stocking rates, respectively. Utilization increased quadratically as grazing pressure index increased, whereas grazing and harvest efficiencies exhibited a linear increase with grazing pressure. The latter indicates that nonlivestock forage losses (e.g., weathering, senescence, wildlife, insects) were disproportional across stocking rates. Average daily gain of livestock decreased linearly as grazing pressure index increased across study sites. Prediction equations reaffirm assumptions of 50% grazing efficiency and 25% harvest efficiency associated with moderate stocking. Novel here, however, is that harvest and grazing efficiencies increased at high grazing pressures and decreased at low grazing pressures. Use of grazing pressure index to ‘‘standardize’’ stocking rates across rangeland ecosystems in the North American Great Plains should improve communication among scientists, resource managers, and the public, and thus better achieve both production and conservation goals on these lands.  The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020

Language
en
Resource Type
Text
Document Type
Journal Issue/Article
Digital Object Identifier (DOI)
10.2111/REM-D-09-00046.1
Additional Information
Smart, A. J., Derner, J. D., Hendrickson, J. R., Gillen, R. L., Dunn, B. H., Mousel, E. M., ... & Olsen, K. C. (2010). Effects of grazing pressure on efficiency of grazing on North American Great Plains rangelands. Rangeland Ecology & Management, 63(4), 397-406.
IISN
0022-409X
OAI Identifier
oai:repository.arizona.edu:10150/642800
Journal Volume
63
Journal Number
4
Journal Pages
397-406
Journal Name
Rangeland Ecology & Management
Keywords
animal performance
forage disappearance
grazing efficiency
harvest efficiency
herbage intake
stocking rate
utilization