1. Setting a Stocking Rate
K. Launchbaugh
K. Launchbaugh
REM Integrated Rangeland Management

2. How do you set stocking rate? Balance supply with demand
Four–Step Method

3. 4-Step “Forage Demand” Method
Calculate usable forage
Adjust for accessibility (terrain or water)
Calculate forage demand of animals
Calculate stocking rate
Supply
Demand

4. 4-Step, Forage Demand Method
The 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

5. Step 1 – Calculate Usable Supply
Start with amount of biomass
Wt of biomass/acre× area = total biomass supply
Convert total biomass to total forage
Not all biomass is forage
Not all biomass should be grazed
Use a “Proper Use Factor” to calculate forage
Total biomass × proper use(%)= total forage supply

6. Step 1 – Calculate Usable Supply
An Example – You manage a 1,200 acre ranch and the average production is 760 lbs/acre. The ranch is located in the intermountain bunchgrass region and based on this vegetation type, a proper use factor would be to remove up to 40% of annual biomass.
What is your usable forage supply?

7. Step 1 – Calculate Usable Supply
An Example – You manage a 1,200 acre ranch and the average production is 760 lbs/acre. The ranch is located in the intermountain bunchgrass region and based on this vegetation type, a proper use factor would be to remove up to 40% of annual biomass.
What is your usable forage supply?
1,200 ac × 760 lbs/ac = 912,000 lbs of biomass × 40%= 364,800 lbs total Forage

8. Step 2 – Adjust for Accessibility
Not all forage is available for grazing:
Slope
Distance from water
National Range and Pasture Handbook
USDA- NRCS

9. Step 2 – Adjust for Accessibility
Adjustments for slope and distance from water are guidelines not rules.
Depends on:
Animal species, breed, and experience
Topography and soils
Season
Temperature
Forage moisture

10. Step 3 - Calculate Forage Demand of Animals
Intake of animals on rangeland or pastures
Horses eat about 3% of their weight/day
Ruminants eat about 2.5% of body weight/day
Ruminants eat 2.5 to 4.0% depending on size:
Animal Weight % of weight/day
1,000-1,500 lbs 2.5 %
500-1,000 lbs 3.0 %
lbs 3.5 %
< 100 lbs 4.0 %
Justin Trujillo
Connor White
Tom Koener (USFWS)

11. Step 3 - Calculate Forage Demand of Animals
If you know:
Weight of animal
Intake Factor (% of body weigh eaten per day)
Number of animal
How many days they graze on the range
Then…. You can calculate total demand per season

12. Step 3 - Calculate Forage Demand of Animals
For example – you manage a herd of beef cows with an average weight of 1,200 pounds and they graze on the ranch for 3 months (or 90 days).
How much air-dry forage would you expect each cow to eat?
1,200 lb cow × 2.5% = 30 pounds forage eaten per day
30 pounds × 90 days = 2,700 lbs/cow/season
For a herd of 55 cows:
2,700 lbs × 55 = 148,500 lbs demand for the whole herd

13. Step 3 - Calculate Forage Demand of Animals in AUMs
Demand can be expressed in AUMS:
AUM= 750 lbs which is 1,000 lbs grazing ruminant × 2.5% to get lbs/day of intake × 30 days in a month
AUE = Animal Unit Equivalent = the proportion of an animal unit that each animal is equivalent to.

14. Step 3 - Calculate Forage Demand of Animals in AUMs
Number of Animals × the AUE for that species and type = AUs
For example,
6 bulls × 1.35 = 8.1 AU
270 goats × 0.15 AUE = 40.5 AU
100 elk × 0.6 AUE = 60 AU
National Range and Pasture Handbook
USDA- NRCS

15. Step 3 - Calculate Forage Demand of Animals in AUMs
Calculate number of AUs:
Number of animals× AUE = AU
Calculate number of AUMs:
AU × number of months grazing= AUMs
For Example - Horses that graze for 6 months
Horse× 1.25 AUE × 6 months = 7.5 AUMs
Express in pounds, if desired:
7.5 AUMs × 750 lbs = 5,625 lbs

16. Step 4 - Calculate Stocking Rate
A stocking rate must include:
Number of animals or animal units
Specified area (acres, hectare, pasture, or ranch)
Specified time (days, months, or season)
The following are stocking rates because they include all 3 of the necessary elements:
Ac/AUM or AUM/Ac
15 cows/35 acre pasture/4 months
Flock of 450 ewes and lambs on ranch for a year

17. 4-Step “Forage Demand” Method
Calculate usable forage
Adjust for accessibility (terrain or water)
Calculate forage demand of animals
Calculate stocking rate
Supply
Demand

18. Variable/Flexible vs Fixed Stocking
Amount of forage varies from year to year
long-term
average
Sharp, L. A., K. Sanders, & N. Rimbey. (1992). Variability of crested wheatgrass production over 35 years. Rangelands. 14:

19. How do you set a stocking rate amidst variability?
1957
Precipitation = 11.7”
Grass Production = 846 lb/ac
1959
Precipitation = 11”
Grass Production = 416 lbs/ac
How do you set a stocking rate amidst variability?
1960
Precipitation = 6.5”
Grass Production = 186 lbs/ac
1971
Precipitation = 16.2”
Grass Production = 1090 lbs/ac
Sharp, L. A., K. Sanders, & N. Rimbey. (1992). Variability of crested wheatgrass production over 35 years. Rangelands. 14:

20. Variable/Flexible vs Fixed Stocking
Amount of forage varies from year to year
long-term
average
Flexible - no more than 60% of herd in breeding stock
Fixed- herd size that could be sustained if rainfall was 25% below average.

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

22. Setting a Stocking Rate
K. Launchbaugh
K. Launchbaugh
REM Integrated Rangeland Management

23. 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

24. Monitoring Approaches
Key Species = a species that indicates use of associated species
Abundant
Productive
Palatable, but not an “ice cream” plant
Provides bulk of forage for grazing animals
Key Area = portion of range which because of location, vegetation community or topography is a used as an indicator of the whole pasture.
Not too remote from water (within 3/4 mile)
Accessible to livestock
No topographic limitations
More than 50 acres.

25. 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 as needed