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Grazing Management Grazing Management Principles for Principles for Rangelands Rangelands Mort Kothmann Mort Kothmann Texas A&M University Texas A&M University
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Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Dec 27, 2015

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Page 1: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Grazing Management Grazing Management Principles for RangelandsPrinciples for Rangelands

Mort KothmannMort Kothmann

Texas A&M UniversityTexas A&M University

Page 2: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Four Basic Principles of Four Basic Principles of Grazing ManagementGrazing Management

►Stocking rateStocking rate►Season of grazingSeason of grazing►Distribution of grazing across Distribution of grazing across

landscapelandscape►Match kinds and classes with the Match kinds and classes with the

rangeland vegetation, topography and rangeland vegetation, topography and climateclimate

Page 3: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Grazing Management Grazing Management ConceptsConcepts

Basic tenets of grazing Basic tenets of grazing managementmanagement

►Grazing intensity (degree of use)Grazing intensity (degree of use) Light – moderate – heavy – extreme Light – moderate – heavy – extreme

►Methods for monitoring degree of Methods for monitoring degree of useuse Key area method (Key species)Key area method (Key species)

Page 4: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Grazing IntensityGrazing Intensity

► A certain amount A certain amount of plant biomass of plant biomass must remain to must remain to maintain to maintain to assure health of assure health of animals, plants animals, plants and soil and soil Herbivore diet Herbivore diet Plant vigor and Plant vigor and

reproductionreproduction Soil stability Soil stability

Page 5: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Grazing IntensityGrazing Intensity

►As annual precipitation declines, As annual precipitation declines, sustainable level of forage utilization sustainable level of forage utilization generally decreases generally decreases Sustainable intensity of grazing is directly Sustainable intensity of grazing is directly

related to availability of water and soil related to availability of water and soil nutrientsnutrients

Greater resource availability increases Greater resource availability increases proportional allocation to shoot relative to proportional allocation to shoot relative to rootroot

Page 6: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Grazing IntensityGrazing Intensity

►Recommended levels of use based on Recommended levels of use based on field estimatesfield estimates and (harvest efficiencies) and (harvest efficiencies) Ryegrass (water & N unlimited) Ryegrass (water & N unlimited) 75%75% (70-80%) (70-80%) Coastal Bermudagrass pasture Coastal Bermudagrass pasture 50%50% (40-60%) (40-60%) Humid tall grassland Humid tall grassland 40-50%40-50% (20-30%) (20-30%) Semiarid grasslands: Semiarid grasslands: 20-30%20-30% (15-20%) (15-20%) Arid SW & Intermountain West: Arid SW & Intermountain West: 15-20%15-20% (10- (10-

15%)15%)

The more arid the land, the lower the sustainable The more arid the land, the lower the sustainable intensity of use.intensity of use.

Page 7: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Monitoring Range UtilizationMonitoring Range Utilization

►Key Species Method for monitoring useKey Species Method for monitoring use

Monitor utilization of 1-3 key species that are Monitor utilization of 1-3 key species that are abundant, productive, and palatable abundant, productive, and palatable ((decreasersdecreasers or increasers) rather than or increasers) rather than monitor many speciesmonitor many species

Assumption: use of entire range is optimal Assumption: use of entire range is optimal when use of key species is optimal:when use of key species is optimal:

►Key species are moderately used – 30-40 %Key species are moderately used – 30-40 %►Secondary species are lightly used – 10-25 %Secondary species are lightly used – 10-25 %►““Ice-cream” plants may be overused – >40 %Ice-cream” plants may be overused – >40 %

Page 8: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Monitoring Range UtilizationMonitoring Range Utilization► Key Area method for monitoring range useKey Area method for monitoring range use

Monitor an area that is “representative” of overall Monitor an area that is “representative” of overall range condition, trend, and degree of seasonal userange condition, trend, and degree of seasonal use

No rangeland is uniformly used – some “sacrifice” No rangeland is uniformly used – some “sacrifice” areas will occur due to area selectivityareas will occur due to area selectivity

►Heavy use – Clipped or mowed appearance Heavy use – Clipped or mowed appearance >50 % of fair or poor forage plants used>50 % of fair or poor forage plants used

►Moderate UseModerate Use 50 % of good or fair forage plants used50 % of good or fair forage plants used

►Light useLight use Only choice plants usedOnly choice plants used

Page 9: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Monitoring Range UtilizationMonitoring Range Utilization

►Key Area method for monitoring range Key Area method for monitoring range use use Optimal stubble height in key areas Optimal stubble height in key areas

following grazing vary:following grazing vary:►Tall-grasses Tall-grasses

30-35 cm (12-14 inches)30-35 cm (12-14 inches)►Mid-grasses Mid-grasses

15-20 cm (6-8 inches)15-20 cm (6-8 inches)►Short-grasses Short-grasses

5-8 cm (2-3 inches)5-8 cm (2-3 inches)

Page 10: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

TGM for Monitoring Degree of TGM for Monitoring Degree of UseUse

►Using the Using the Demand DayDemand Day (DD) as a (DD) as a measure of animal production and measure of animal production and maintenance from the pasture.maintenance from the pasture. Energy required for maintenance and Energy required for maintenance and

growth is estimated from animal weights growth is estimated from animal weights and expressed as DD.and expressed as DD.

Productivity of the pastures is estimated Productivity of the pastures is estimated from observed animal production and from observed animal production and degree of use on the pasture.degree of use on the pasture.

Page 11: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Season of UseSeason of Use

► YearlongYearlong

Used primarily in tropical & sub-tropical climatesUsed primarily in tropical & sub-tropical climates

► SeasonalSeasonal

Temperate to cold climatesTemperate to cold climates

Tame pasturesTame pastures

► RotationalRotational

Grazing Systems (This will be covered in a Grazing Systems (This will be covered in a separate presentation.)separate presentation.)

Page 12: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Length of Length of Grazing Season vs Growing Grazing Season vs Growing

SeasonSeason► RangelandsRangelands– Grazing season is generally – Grazing season is generally

longer than the growing season. This requires longer than the growing season. This requires stockpiling forage for use during the non-stockpiling forage for use during the non-growing season. This frequently involves very growing season. This frequently involves very light use during the peak growing season.light use during the peak growing season.

► Tame PastureTame Pasture– Grazing season is matched – Grazing season is matched with the growing season to harvest forage with the growing season to harvest forage near maximum quality. Stockpiling forage near maximum quality. Stockpiling forage usually involves shortening the grazing period usually involves shortening the grazing period during active growth.during active growth.

Page 13: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Timing of GrazingTiming of Grazing► Effect of grazing varies according to:Effect of grazing varies according to:

Season of use Season of use -- Plants are more resistant to -- Plants are more resistant to intense herbivory during dormancy than in intense herbivory during dormancy than in active growth.active growth.

Phenological stage of plantPhenological stage of plant -- Defoliation in -- Defoliation in spring when plants start growth may be less spring when plants start growth may be less harmful than in fall when plants are flowering harmful than in fall when plants are flowering and maturing.and maturing.

Opportunity for regrowthOpportunity for regrowth – Will plants be – Will plants be able to produce new leaves and develop strong able to produce new leaves and develop strong root systems prior to entering dormancy root systems prior to entering dormancy following defoliation?following defoliation?

Page 14: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Grazing Distribution:Grazing Distribution:Animal SelectivityAnimal Selectivity

►Area distributionArea distribution LandscapeLandscape PatchPatch Feeding stationFeeding station

►Species selective grazingSpecies selective grazing►Plant part selective grazingPlant part selective grazing

Live or deadLive or dead Leaf of stemLeaf of stem

Page 15: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Area SelectionArea Selection

►Factors affecting area selection include:Factors affecting area selection include: Distance from WaterDistance from Water Vegetation TypeVegetation Type Topography (Slope)Topography (Slope) Range Site (Soils)Range Site (Soils) WeatherWeather Animal pests such as fliesAnimal pests such as flies Kind & class of animalKind & class of animal Management practices such as Management practices such as

supplementationsupplementation

Page 16: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Distance from WaterDistance from Water

►Recommended distances between Recommended distances between watering points vary according to watering points vary according to terrain, species of animal, and breed of terrain, species of animal, and breed of livestock livestock

►General recommendations:General recommendations: Rough country: ≈ 0.5-mile maxRough country: ≈ 0.5-mile max Rolling country: 1.0-mile maxRolling country: 1.0-mile max Flat sandy country: ≈ 1.5-mile maxFlat sandy country: ≈ 1.5-mile max Flat country ≈ 2.0-mile maxFlat country ≈ 2.0-mile max

Page 17: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Vegetation TypeVegetation Type

►Herbivores select areas with Herbivores select areas with vegetation that best meets their vegetation that best meets their nutritional needs nutritional needs Bulk grazers prefer open grasslandsBulk grazers prefer open grasslands

►Cattle, Buffalo, White rhinosCattle, Buffalo, White rhinos

Browsers prefer wooded areasBrowsers prefer wooded areas►Mule deer, Giraffes, Black rhinosMule deer, Giraffes, Black rhinos

Page 18: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

TopographyTopography

CattleHorsesDeerBighorn

Percent Slope

Pe

rce

nt o

f Obs

erv

atio

ns

10

20

30

40

50

60

70

10 20 30 40 50 60 70 80+

Figure 10.2 Relationship of slope gradient to the percentage of observations of cattle, feral horses, deer, and bighorn sheep. (From Ganskopp and Vavra 1987. Reprinted with permission.)

Page 19: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Improving Livestock Improving Livestock DistributionDistribution

►Provide supplemental feeds/mineral Provide supplemental feeds/mineral lickslicks Cattle move from water to grazing to salt:Cattle move from water to grazing to salt:

►Change location of salt-mineral licksChange location of salt-mineral licks►Place salt away from water in areas that Place salt away from water in areas that

grazing animals are avoiding grazing animals are avoiding

►Grazing systems that reduce pasture Grazing systems that reduce pasture size and significantly increase animal size and significantly increase animal density may improve livestock grazing density may improve livestock grazing distribution.distribution.

Page 20: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Improving Livestock Improving Livestock DistributionDistribution

►Prescribed burningPrescribed burning

Removal of previous years’ growthRemoval of previous years’ growth►Greater access to new plant growthGreater access to new plant growth

Early spring fires can Early spring fires can ►Increase soil temperatureIncrease soil temperature►Initiate growthInitiate growth►Improve forage qualityImprove forage quality►Encourage earlier grazingEncourage earlier grazing

Page 21: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Improving Livestock Improving Livestock DistributionDistribution

►Adjust kind/class of livestockAdjust kind/class of livestock Changing animal species can improve Changing animal species can improve

livestock distribution depending on:livestock distribution depending on:►Vegetation compositionVegetation composition►Water distributionWater distribution►Topography Topography

Because of non-uniform plant composition, Because of non-uniform plant composition, multi-species animal production systems multi-species animal production systems can increase:can increase:

►Herbivore distribution Herbivore distribution ►Vegetation use Vegetation use ►Animal productionAnimal production

Page 22: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Improving Livestock Improving Livestock DistributionDistribution

►Fencing can be used to control:Fencing can be used to control: Area selective grazingArea selective grazing Season of useSeason of use Rotational grazing systemsRotational grazing systems

Use of high-value forages such as hay Use of high-value forages such as hay cropscrops

Movement of wildlifeMovement of wildlife

Page 23: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Livestock DistributionLivestock Distribution

►Negative Aspects of Fencing Negative Aspects of Fencing Cost prohibitive where productivity is Cost prohibitive where productivity is

lowlow Electric fences are less costly to Electric fences are less costly to

construct than standard barbed wire construct than standard barbed wire but more expensive to maintainbut more expensive to maintain

Restrict movement of some wild Restrict movement of some wild speciesspecies

High-fencing to control game speciesHigh-fencing to control game species

Page 24: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Kind & Class of AnimalKind & Class of Animal

► Kind of animal (species)Kind of animal (species) Cattle, sheep, goat, horse, wildlife speciesCattle, sheep, goat, horse, wildlife species

► Class of animal (age, sex, physiological Class of animal (age, sex, physiological status)status) Reproductive -- pregnant or openReproductive -- pregnant or open Age -- mature or youngAge -- mature or young Lactating or dryLactating or dry

► Adaptation to climate and forage qualityAdaptation to climate and forage quality Breed of animalBreed of animal Genetic potential for growth and lactationGenetic potential for growth and lactation

Page 25: Grazing Management Principles for Rangelands Mort Kothmann Texas A&M University.

Choice of Kind & Class of Choice of Kind & Class of AnimalsAnimals

►Match animal genetics with forage Match animal genetics with forage qualityquality

►Match the grazer with the landscape Match the grazer with the landscape and the kinds of vegetationand the kinds of vegetation