Stocking Rate Calculator

Enter the available forage in lbs/acre
Enter the pasture size in acres
0% Reduction
Recommended: 31-40% for conservative grazing. Enter the percentage of forage that will be allocated for grazing
Select the animal type to calculate appropriate stocking rate. Values based on Animal Unit Equivalent (AUE)
Enter the grazing period in days

Calculation Results

-
acres (after terrain adjustment)
-
lbs (based on adjusted grazable area)
-
lbs
-
Animal Units (AUs) for the entire pasture
-
AUs/acre
-
Total AUMs available

Adjustment Factor Guidelines

Choose the factor with the greatest reduction (slope or water distance - not both).

Slope Guidelines:
0-10% slope 0% reduction
11-30% slope 30% reduction
31-60% slope 60% reduction
>61% slope 100% reduction
Water Distance Guidelines:
0-1 mile 0% reduction
1-2 miles 50% reduction
>2 miles 100% reduction
Important: Evaluate both slope and water distance for your pasture, then use whichever factor results in the greater reduction. Do not combine both adjustments.

How to Calculate Available Forage

Available forage (lbs/acre) can be calculated using the Rapid Assessment Methodology (RAM) from your monitoring procedures. Follow steps 10-11 from the monitoring procedures:

Step 10: Dry Forage Samples

  1. Use a low temperature (less than 140° F) drying oven and dry bags for 24 hours.
  2. Alternatively, place bags on vehicle dashboard in direct sunlight until forage is completely dry (~48 hours).
  3. Determine forage sample mass: weigh sample plus bag, subtract bag mass, record sample mass in grams for each clipping or sample.

Step 11: Convert to Pounds per Acre

  1. Find the conversion factor from the table below based on your sample hoop size.
  2. To estimate forage production from exclusion cage samples:
    • Add all exclusion cage samples together and divide by the number of cage samples collected.
    • Multiply the resulting quotient by the appropriate conversion factor.
Conversion Factors:
Plot Size Conversion Factor
0.96 ft² grams × 100
1.92 ft² grams × 50
2.40 ft² grams × 40
4.80 ft² grams × 20
Example: If you collected 5 transect samples totaling 250 grams using a 0.96 ft² hoop, your available forage = (250 ÷ 5) × 100 = 5,000 lbs/acre.
Note: For more detailed instructions, refer to the Monitoring Procedures section of this website.

About Stocking Rate Calculation

Stocking rate is the number of animal units (AUs) that can graze a given area for a specified period of time. This calculator helps you determine the appropriate stocking rate based on available forage, pasture size, and grazing duration.

Key Definitions:

  • Animal Unit (AU): A standard unit for comparing forage consumption across different livestock. The baseline is a 1,000 lb cow with calf consuming 27 lbs of dry forage per day
  • Animal Unit Equivalent (AUE): A conversion factor that expresses the forage consumption of different animal types relative to the standard AU. For example, a mature bull (1850 lbs) = 1.5 AU, while a mature sheep = 0.15 AU
  • Forage Allocation: The percentage of available forage that will be allocated for grazing (typically 31-40% for conservative grazing)
  • Terrain Adjustment: Optional reduction in grazable area due to slope or water distance. Click the info icon to see guidelines for determining which factor to use
  • Animal Unit Month (AUM): The amount of forage required by one AU for one month

How to Use:

  1. Enter your available forage in lbs/acre (this can be obtained from your RADAR report)
  2. Enter your pasture size in acres
  3. (Optional) Adjust the terrain slider to account for slope or water distance:
    • Click the info icon () to view slope and water distance guidelines
    • Evaluate both factors and use whichever has the greater reduction
    • Do not combine both adjustments
  4. Adjust the forage allocation (31-40% is recommended for conservative grazing)
  5. Select your animal type from the dropdown (includes cattle, horses, sheep, goats, bison, and wildlife)
  6. Enter the planned grazing period in days
  7. Click "Calculate Stocking Rate" to see your results

Note: The calculator automatically adjusts forage requirements based on the selected animal type using Animal Unit Equivalent (AUE) values from USDA-NRCS Montana Table 6-5.

Note: This calculator provides estimates based on standard formulas. Actual stocking rates should consider factors such as forage quality, animal type and size, terrain, water availability, and environmental conditions. Always consult with a range management specialist for site-specific recommendations.

Reference:
USDA-NRCS. 2015. Montana Table 6-5: Animal Unit Equivalent Guide (NRPH, Supplement MT9, Apr. 2006), Chapter 6: Livestock Nutrition, Husbandry, and Behavior, National Range and Pasture Handbook.