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Chapter 9: Selection of grazing methods 1. Definition of terms 2. Consideration in grazing system selection 3. Comparisons of the different grazing systems 4. Detailed evaluation of short duration grazing 5. Grazing systems for riparian zones 6. Economics of grazing systems 7. Review of grazing system studies
Stocking vs. Specialized grazing systems Range research shows stocking rate has had a much bigger impact on range vegetation and financial returns than specialized grazing systems. Specialized grazing systems will not overcome the impacts of excessive stocking.
Grazing systems Grazing systems – manipulation of livestock grazing to accomplish a desired result. Objectives of grazing system: a. defer or rest key species b. obtain more uniform use of forage crop c. increase livestock productivity d. provide opportunity for sacrifice areas to recover e. increase wildlife productivity
Some terminology Specialized grazing systems - grazing systems other than continuous or season long that involve scheduled moves of livestock during the grazing season. Deferment – delay of grazing in a pasture until seed maturity of key species. Rest - non use of a pasture for one year (12 months) Rotation – movement of livestock from one pasture to another on scheduled basis.
Considerations involving grazing systems 1. Vegetation 2. Livestock 3. Wildlife 4. Watershed protection 5. Labor 6. Developments a. fence b. Water 7. Climate
1. Rugged topography 2. Wildlife are and important consideration 3. High diversity in forage resources 4. More than one type of livestock will be grazed 5. Poor water distribution 6. Poor distribution of precipitation over the range occurs within years ( the Southwestern United States) 7. Timbered areas where carefully timed grazing is necessary to prevent tree damage 8. Vegetation has low resistance to grazing Conditions where specialized grazing systems are most useful:
Types of grazing systems 1. Continuous 2. Season long 3. Deferred rotation 4. Rest rotation 5. Short duration 6. Best pasture 7. Seasonal suitability 8. High intensity – low frequency 9. Merrill 3 herd/4 pasture
Continuous Grazing 1. Works well in flat desert areas 2. Works well in flat shortgrass prairie areas 3. Works well in California annual grassland 4. Require the least fence of all the systems 5. Has given better livestock performance than rotation systems
Deferred Rotation Grazing 1. Works well in coniferous forest 2. Works well in tallgrass prairie 3. Developed by Dr. Arthur Sampson in northeastern Oregon around 1906
Rest Rotation Grazing 1. Works well in rugged terrain 2. Works well for well for riparian enhancement, wildlife, fish and other multiple use values if grazing is light to moderate in grazed pastures 3. Developed by Gus Hormay on Forest Service rangelands in the 1950’s
Table 19. Effects of year-long and Santa Rita rest-rotation grazing on vegetation on semi-desert rangeland in southeastern Arizona._______________________________________ Characteristic Grazing yearlong Grazing System rest- rotation _____________________________________________________ Duration of study (years) 10 10 Annual precipitation (inches) 14 14 % use of forage 52 49 Perennial grass production (lb/ac) 391 360 Perennial grass density (plants/m2) 17.2 19.3 It was concluded Santa Rita rest-rotation grazing had no benefit over year-long grazing on rangelands in high ecological condition but may have benefits for degraded rangelands (source Martin and Severson, 1988).
Short Duration Grazing (Savory grazing approach) Best suited to flat, humid areas Requires the most fence of all the systems Developed by Mr. Alan Savory in Zimbabwe Africa
Table 16. Effects of continuous and short- duration grazing on blue grama rangeland in south-central New Mexico Grazing systems Characteristics Continuous Short duration Duration of study (years) 5 5 Annual precipitation (inches) 17.91 16.14 % forage use Not Given Herbage production (lbs./acre) 1,067 1,080 Blue grama production (lbs./acre) 424 397 Range trend Stable/up Stable/up Cow conception rate (%) 100 86 Calf weaning wts. (lbs.) 524 467 Average daily gain (lbs.) 1.17 1.10 Gain per acre (lbs.) Not Given
Table 16b. It was concluded differences in vegetational responses to short duration and continuous grazing were small. Results indicated that cow-calf performance under short duration was less than under moderate continuous grazing. The authors concluded their studies shows the overriding of stocking rate on livestock performance. Sources: White, M.R., R.D. Pieper, G.B. Donart and L. White-Trifaro. 1991; Parker, E.E., G.B. Donart, R.D. Pieper, J.D. Wallace, and J.D. Wright. 1987.
Table 17. Effects of season-long, deferred rotation and time controlled on vegetation and cattle on vegetation and cattle on short grass range in Wyoming. Characteristic Season-long Deferred Time rotation controlled Duration of study (years) 13 13 13 Annual precipitation (inches) 15.1 15.1 15.1 Use of forage (%) 40 40 40 Acres/steer 5 5 5 Forage production (lbs./acre) No difference Range trend No difference Steer gains (lbs./acre) No difference Financial returns ($/acre) 15.20 13.72 12.07 Sources: Hart, R.H., M.J. Samuel, P.S. Test and M.A. Smith. 1988. Cattle, vegetation and economic responses to grazing systems and grazing pressure. J. Range Manage. 41:282-286, Manley, W.A., R.H. Hart, J.W. Waggoner Jr., and J.T. Manley.1997. Vegetation, cattle and economic responses to grazing strategies and pressure. J. Range Manage.50:638-646.
Table 18. Effects of grazing systems on yearling cattle production on tallgrass prairie rangeland in Oklahoma. Characteristic Short duration Season long Duration of study (years) 6 6 Annual precipitation (inches)1 31 31 Estimated use of forage (%) 50-55 50-55 Stocking rate (AUD’s/acre)2 28 28 Forage production (lbs./acre)3 3,200 2,670 Range trend Stable Stable Gain per steer (lbs) 238 264 Gain per acre (lbs) 62 74 Net returns ($/acre) 2.83 8.50 1 precipitation during study was 127% long term average. 2 AUD=Animal Unit Day. 3 Forage standing crop in September Sources: Gillen, R.L., F.T. McCollum, K.W. Tate and M.B. Hodges. 1998. Tallgrass prairie response to grazing system and stocking rate. J. Range Manage 51:139-146. McCollum, F.T., R.L. Gillen, B.R. Karges and M.E. Hodges. 1999. Stocker cattle response to grazing management in tallgrass prairie. J. Range manage. 52:120-126.
Best Pasture Grazing 1. Works well in southwestern United States where rainfall is highly uneven across ranches and landscapes 2. Was designed by Ken Valentine, a deceased professor from New Mexico State University 3. Has been studied at two locations in New Mexico
Table 14. Rangeland and Cattle production characteristics for different grazing management Strategies on Chihuahuan Desert Rangelands, South-central New Mexico 1967- 1986. Conservative Conservative Characteristics continuous best pasture Duration of study (years) 25 25 Average precipitation (inches) 9.3 9.3 Average perennial grass production (lbs/acre) 151 145 Range trend up up Range condition good/excellent good % forage use 20-30 20-30 Calf crop (%) 82 84 Calf weaning wt (lbs) 486 469 Estimated gain/acre (lbs) 2.04 2.02 Sources: Beck, R.F., 1978; Beck, R.F. and R.P. McNeely, 1993.
Seasonal Suitability Grazing First developed by C. Wayne Cook in Utah in l950’s Designed for areas and ranches where forage resources are diverse (Intermountain West) Involves using each plant community when best for livestock
Seasonal suitability grazing • Complementary grazing – Coordination of grazing to plant and animal requirements so that vegetation and livestock production are optimized on a sustained basis.
High Intensity-Low Frequency Grazing 1. Works best in flat, humid areas 2. Gives the worst livestock performance of all the grazing systems because livestock are forced to eat plants of low palatability