Guidelines for Setting “Proper” Stocking Rate

K. Launchbaugh UDSA-ARS

Natural &Human

Resources

GrazingManagement Decisions

Community Response

Climate

Topography

Veg. Community

Wildlife

Mgmt. Philosophy& Goals

LivestockSpecies• cattle, sheep, goats

or horses

Stocking Rate• how many

animals

Grazing System• season of grazing• season of rest• duration of grazing

Vegetation Community

Livestock Production

Wildlife Community

Important point: Once grazing management decisions are made, there

are continual interactions between livestock, wildlife, & vegetation

Four Grazing Mgmt Factors: Which animal? -Animal Species & Class How many animals? -Stocking Rate When to grazing or not graze? -Grazing System Where animals graze? – Grazing Distribution

Carrying CapacityThe number of animals that a piece of land can support on a long-term basis without causing damage to the ecosystem.

• Land and vegetation determine grazing capacity

• Expressed as animals/area/year (usually acres per AUM per year)

• Land is usually bought and sold on this basis

Stocking RateThe number of animals a land manager places on a piece of land for a specified period of time.

• Must include:• Number of animals or Animal Unit• Specific area (acres or hectares)• Specific period of time (days or months)

• Most important grazing decision because it affects:• Rangeland health• Economic returns

Animal Unit (AU) 1,000 pounds of grazing animal … ruminant

AUE #/AUCow = 1 1Horse = 1.8 .56Yearling Steer = .75 1.3Sheep = .2 5Jackrabbit = .02 50

Animal Unit Equivalent (AUE) = A conversion factor reflecting the # of AU in an average animal

** See assigned reading from more examples

Forage Demand of Animal

Ruminants Eat 2.5% of body

weight/day in dry matter of forage.

Cattle, sheep, goats Deer, elk, bighorn sheep,

moose, etc.

Hind-Gut Fermentors Eat 3.0% of body

weight/day in dry matter of forage.

Horses Rabbits and rodents

Animal Unit Month (AUM)

Amount of forage an AU will eat in a month

–How many pounds is this?

Animal Unit Month (AUM)

Amount of forage an AU will eat in a month

–Grazing ruminant animals eat about 2.5% body weight per day. –30 days in month– How much is an AU?

Animal Unit Month (AUM)

Amount of forage an AU will eat in a month

–Grazing ruminant animals eat about 2.5% body weight per day. –30 days in month– How much is an AUM?

Each AU = 1,000 lbs ×2.5% = 25 lbs/day AUM= 25 lb * 30 days = 750 lbs

Proper stocking rate? Range Health standpoint

Basis for Stocking RatesProper stocking based on maintaining sufficient plant

residue for:◦ Plant health/regrowth◦ Wildlife forage◦ Erosion prevention

Set stocking rate below carrying capacity◦ To allow for drought◦ To allow for low productivity years

Utilization Guidelines: Based on ecological research

% Use of Major Plants30-4040-5030-4030-40

Range Type

Sagebrush grasslandsShortgrass prairieConiferous ForestOak woodlands

http://forestandrange.org/modules/livestockwildlife/edu/Presentation6.ppt

Root Response to Defoliation

Importance of rootsRemove the Leaves ----- Affect the Roots

Root Responses to Defoliation50% 70% 90% Level of Removal

Root Responses to Defoliation

Basis for “Allowable Use” or “Recommended Use” Levels

Total Forage × Recommended Use = Usable Forage Supply

Heavy use ≠ Overgrazing Overgrazing = repeated heavy grazing such that

damage to the plant community occurs

Overstocking = heavy grazing during a specific season such that high levels of utilization are observable.

Overstocking does not always lead to Overgrazing

For Rangeland Health: Set Stocking Rates Below Carrying Capacity

Healthy soil. Slows weedy plant invasion. Improves drought resistance. Improves condition of degraded land.

Proper stocking rate? Animal Production standpoint

Stocking rate affects cattle gains:

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50

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MAY JUNE JULY AUG SEP OCT

ste

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ga

in (

lbs

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Stocking rate affects cattle gains:

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sive

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stocking rate

Production per animal

Stocking rate affects total production:

Low

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stocking rate

Production per acre

Proper stocking rate

Bement 1969

Desirable production per animal

Optimal production of animals per acre

What is “Desirable” or “Optimal” depends on the manager’s goals and objectives.

For Livestock Production: Set Stocking Rates At or Below Carrying Capacity

How do you set stocking rate? Balance supply with demand

Simple Four–Step Method

4-step or Forage Demand Method Calculate usable forage Adjust for terrain, water, or other constraints Calculate forage demand of animals Calculate stocking rate

4-step or Forage Demand MethodThe forage demand method is used: When you have no stocking information from

previous years To estimate carrying capacity in biological

surveys or land appraisal When considering changes in kind or class of

animals

Flexible vs. Constant stocking:

Amount of forage varies from year to year

long-termaverage

Flexible - no more than 60% of herd in breeding stock

Constant - herd size that could be sustained if rainfall was 25% below average.

Establish stocking rate based on: Past experience Current situation Long-range weather forecast Financial goals Etc.

Set a Stocking Rate and Then Monitor!

With this method stocking rate is determined by trial and error over years and then monitored by:

Range Trend = changes in plant composition or rangeland health over time

Grazing Principles Which animal -Animal Species & Class How many animals -Stocking Rate When to grazing or not graze -Grazing System

Match number and type of animal to the rangeland vegetation, topography and climate

Grazing Capacity Summary Use caution when estimating grazing capacity Combine

Utilization measurements Interpretation of current range condition Knowledge of past and present stocking

Monitor! Adjust when needed!