A simple deterministic model was developed to predict animal unit months (AUM's) and live weight gains of beef cattle grazing specific range types in eastern Oregon. The model can provide values for 3 levels of spatial resolution (pasture, mapping unit, and slope/ proximity to water "cells" within map ping units) and 5 monthly periods from May 15 to October 14. Operation of the model begins by calculating forage availability as a factor of forage biomass, usable acres, and desired forage utiliza tion. Grazing capacity (AUM's) is calculated by comparing forage availabil ity with the dry matter forage requirement of a 1,000 lb animal unit for 30 days. Live weight gains are calculated by comparing forage availability to dry matter forage intake, crude protein intake, and digestible energy intake of yearling heifers. The model can be used in planning range improvements and coordinating livestock management with other rangeland activities.
Clary, W.P., M.B. Baker, P.F. O'Connell, T.N. Johnsen, and R.E. Campbell.1974. "Effects of pinyon-juniper removal on natural resource products and uses in Arizona." USDA For. Serv. Res. Pap. RM-128. 28 p.
2.
Coe, P.I., and T.M. Quigley.1986. "Application of a geographic information system for the Oregon Range Evaluation Project, "pp. 88-98. Proc. Geographic Information Workshop. Amer. Soc. for Photogrammetry and Remote Sensing. Falls Church, VA.
3.
Cook, C.W.1966. "Factors affecting utilization of mountain slopes by cattle ." J. Range Manage.,19:200-204.
4.
Cordova, F.J., J.D. Wallace, and R.D. Piper.1978. "Forage intake by grazing livestock: a review." J. Range Manage.,31:430-436.
5.
Franklin, J.F., and C.T. Dymess.1973. "Natural vegetation of Oregon and Washington ." USDA For. Serv. Gen. Tech. Rep. PNW-8. 417 p.
6.
Garrison, G.A., A.J. Bjugstad, D.A. Duncan, M.E. Lewis, and D.R. Smith.1977. "Vegetation and environmental features of forest and range ecosystems." USDA For. Serv. Agric. Handbk . 475. 68 p.
7.
Gillen, R.L., W.C. Krueger, and R.F. Miller.1984. "Cattle distribution on mountain rangeland in northeastern Oregon." J. Range Manage.,37:549-553.
8.
Heady, H.F.1975. Rangeland Management. McGraw-Hill Co. , New York. 460 p.
9.
Holechek, J.L.1980. "The effects of vegetation type and grazing system on the performance, diet, and intake of yearling cattle." Ph.D. Diss., Oregon State Univ., Corvallis. 247 p.
10.
Holechek, J.L., and M. Vavra.1982. "Forage intake by cattle on forest and grassland ranges." J. Range Manage.,35:737-741.
11.
Holechek, J.L., M. Vavra, and J. Skovlin.1981. "Diet quality and performance of cattle on forest and grassland range." J. Anim. Sci.,53:291-298.
12.
Holechek, J.L., M. Vavra, J. Skovlin, and W.C. Krueger.1982a. "Cattle diets in the Blue Mountains of Oregon, I. Grasslands." J. Range Manage., 35:109-112.
13.
Holechek, J.L., M. Vavra, J. Skovlin, and W.C. Krueger.1982b. "Cattle diets in the Blue Mountains of Oregon, II. Forests" J. Range Manage., 35:239-242.
14.
Kahn, H.E., and C.R.W. Spedding .1983. "A dynamic model for the simulation of cattle herd production systems: Part 1- General description and the effects of simulation techniques on model results." Agric. Syst.12:101-111.
15.
Lower, O.J., and E.M. Smith.1986. "The Kentucky beef-forage model," pp. 63-100, IN: Spreen, T.H., and D.H. Laughlin (eds.). Simulation of beef cattle production systems and its use in economic analysis. Westview Press , Boulder, CO. 269p.
16.
MacNeil, M.D., J.W. Skiles, and J.D. Hanson.1985. "Sensitivity analysis of a general rangeland model." Ecol. Modelling.29:57-76.
17.
McInnis, M.L., and M. Vavra.1987. "Dietary relationships among feral horses, cattle, and pronghorn in southeastern Oregon." J. Range Manage.,40:60-66.
18.
Mueggler, W.F.1965. "Cattle distribution on steep slopes." J. Range Manage.,18:255-257.
19.
Pickford, G.D., and E.H. Reid.1948. "Forage utilization on summer cattle ranges in eastern Oregon." USDA Circ.796. 27 p.
20.
Quigley, T.M., H.R. Sanderson, and A.R. Tiedemann, 1989. "Managing interior northwest rangelands: The Oregon range evaluation project." USDA For. Serv. Gen. Tech. Rep. PNW-GTR-238, p. 207.
21.
Rice, R.W., M.D. MacNeil, T.G. Jenkins, and L.J. Koong.1983. "SPUR livestock component." pp. 74-87. In: Wright, J.R. (Ed.). 1983. "SPUR — Simulation of production and utilization of rangelands: A rangeland model for management and research." U.S.D.A., Misc. Publ. 1431.120p.
22.
Roath, L.R., and W.C. Krueger.1982. "Cattle grazing and behavior on a forested range." J. Range Manage.,35:332-338.
23.
Sanders, J.O., and T.C. Cartwright .1979a. "A general cattle production systems model. I: Structure of the model." Agric. Syst.4:217-227.
24.
Sanders, J.O., and T.C. Cartwright .1979b. "A general cattle production systems model. Part 2 - Procedures used for simulating animal performance ." Agric. Syst.4:289-309.
25.
Sanderson, H.R., T.M. Quigley, and L. Spink.1988a. "Development and implementation of the Oregon Range Evaluation Project." Rangelands10:17-23.
26.
Sanderson, H.R., T.M. Quigley, and A.R. Tiedemann.1988b. "Response of herbage and browse production to six range management strategies." Rangelands (in press).
27.
Skiles, J.W.1984. "A review of animal preference," pp. 153-213. In: Natl. Resour. Counc./Natl. Acad. Sci., Developing strategies for rangeland management . Westview Press. Boulder, CO. 2022 p.
28.
Sneva, F.A., and C.M. Britton.1983. "Adjusting and forecasting herbage yields in the intermountain big sagebrush region of the steppe province." Agric. Exp. Sta. Bull.659. Oregon State Univ., Corvallis. 61 p.
29.
Sneva, F.A., and L.D. Calvin.1978. "An improved Thiessen grid for eastern Oregon: an interstation correlation study determining the effect of distance, bearing, and elevation between stations upon the precipitation correlation coefficient." Agric. Meteor.,19:471-483.
30.
Svejcar, T., and M. Vavra.1985. "Seasonal forage production and quality on four native and improved plant communities in eastern Oregon." Agric. Exp. Sta. Tech. Bull.149. Oregon State Univ., Corvallis. 24 p.
