Chapter 9: Selection of grazing methods

1. Definition of terms2. Consideration in grazing system selection3. Comparisons of the different grazing

systems4. Detailed evaluation of short duration grazing 5. Grazing systems for riparian zones6. Economics of grazing systems7. 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 speciesb. obtain more uniform use of forage cropc. increase livestock productivityd. 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 systems1. Vegetation2. Livestock3. Wildlife4. Watershed protection5. Labor 6. Developmentsa. fenceb. Water7. Climate

Conditions where specialized grazing systems are most useful: 1. Rugged topography2. 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

Types of grazing systems

1. Continuous 2. Season long3. Deferred rotation4. Rest rotation 5. Short duration6. Best pasture7. Seasonal suitability8. High intensity – low frequency9. 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 Systemrest- rotation

_____________________________________________________Duration of study (years) 10 10Annual precipitation (inches) 14 14% use of forage 52 49Perennial grass production (lb/ac) 391 360Perennial 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

Grazing systemsCharacteristics Continuous Short duration

Duration of study (years) 5 5

Annual precipitation (inches) 17.91 16.14% forage use Not GivenHerbage production (lbs./acre) 1,0671,080Blue grama production (lbs./acre) 424 397Range trend Stable/up Stable/upCow conception rate (%) 100 86

Calf weaning wts. (lbs.) 524 467 Average daily gain (lbs.) 1.17 1.10Gain per acre (lbs.) Not Given

Table 16. Effects of continuous and short-Table 16. Effects of continuous and short- duration duration grazing on blue grazing on blue

grama grama rangeland in south- rangeland in south-central New Mexicocentral New Mexico

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.

Characteristic Season-long Deferred Time

rotation controlled

Duration of study (years) 13 13 13 Annual precipitation (inches) 15.1 15.1 15.1Use of forage (%) 40 40 40

Acres/steer 5 5 5Forage production (lbs./acre) No differenceRange trend No difference Steer gains (lbs./acre) No differenceFinancial 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 17. Effects of season-long, deferred rotation and time Table 17. Effects of season-long, deferred rotation and time controlled on vegetation and cattle on vegetation and cattle on controlled on vegetation and cattle on vegetation and cattle on short grass range in Wyoming.short grass range in Wyoming.

Characteristic Short duration Season long

Duration of study (years) 6 6

Annual precipitation (inches)1 31 31Estimated use of forage (%) 50-55 50-55Stocking rate (AUD’s/acre)2 28 28Forage production (lbs./acre)3 3,200 2,670 Range trend Stable StableGain per steer (lbs) 238 264Gain per acre (lbs) 62 74Net 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.

Table 18. Effects of grazing systems on Table 18. Effects of grazing systems on yearling cattle production on tallgrass prairie yearling cattle production on tallgrass prairie rangeland in Oklahoma.rangeland in Oklahoma.

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

Conservative ConservativeCharacteristics continuous best pasture

Duration of study (years) 25 25Average precipitation (inches) 9.3 9.3Average perennial grass production (lbs/acre) 151 145Range trend up upRange condition good/excellent

good% forage use 20-30 20-30Calf crop (%) 82 84Calf 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.

Table 14. Rangeland and Cattle production Table 14. Rangeland and Cattle production characteristics for different characteristics for different

grazing grazing management Strategies on management Strategies on Chihuahuan Chihuahuan Desert Rangelands, Desert Rangelands, South-central New South-central New Mexico 1967- Mexico 1967- 1986.1986.

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.

Southwest

Black grama

Winter

Tobosa grass

Summer

Creosotebush

Spring

Drought

Lehman lovegrass

Early Fall

Mesquite/

Mesa Dropseed

Early summer

Northwest

Winterfat

Black sage

Winter

Cheat

grass

Early

Spring

Crested wheatgrass

Spring

Native

Bunch

grass

Summer

Crested wheatgrass

Fall

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

Merrill Three herd – Four pasture System

1. Designed for areas when effective precipitation can occur anytime during the year (South Texas).

2. Can be modified for New Mexico rangelands3. Best studied of all grazing systems4. Has proven superior to continuous grazing5. Developed by Leo B. Merrill in Texas in the

l950’s6. Works well for common use grazing and for

wildlife

Development and Evaluation of Multi-Herd/Variable Stocking

A. Study area involves 200,000 acre ranch with 30 pastures in west- central New Mexico

B. Five years of data collected C. Initial results look very promising in terms of increased

forage production, increased livestock production and and increased financial returns

D. Key features- 25% of land receives deferment or rest depending on need, each pasture stocked in accordance with annual forage production and its condition, wildlife and riparian needs are taken into account when stocking rates, grazing timing and grazing frequency are assigned each year, system incorporates flexibility and adaptive management

Grazing Systems for Riparian Zones