Pasture Rotation and Paddock Size Planner
Size a rotational grazing paddock from herd dry-matter demand and measured forage, then calculate how many paddocks and how much total grazeable area are needed for the target recovery period.
Rotation inputs
Private by design: calculations run on this device. The planner does not transmit or store pasture, herd, or forage inputs.
Rotation plan
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How to Use the Paddock Planner
- Enter the herd. Enter the animals that will move together, their average live weight, and an appropriate dry-matter intake estimate.
- Measure forage. Enter standing dry matter, a target residual for the actual forage species and management objective, and a harvest-efficiency allowance for grazing losses.
- Set rotation timing. Choose the occupation time and recovery target. Shorter occupations usually require smaller allocations and more moves. Recovery should follow plant readiness, not the calendar alone.
- Check available area. Compare the complete rotation with grazeable pasture. If the rotation needs more area than entered, change only assumptions that are justified by field measurements and the management plan.
- Monitor and adjust. Move livestock according to measured residual, regrowth, animal performance, weather, and ground conditions. Use temporary fencing, supplemental feed, or a sacrifice area when appropriate.
Formulas and Assumptions
Daily herd demand = animals × average live weight × (daily dry-matter intake ÷ 100)
Usable forage per area = (pre-graze dry matter − target residual) × (harvest efficiency ÷ 100)
Paddock area = daily herd demand × grazing days ÷ usable forage per area
Minimum paddocks = ceiling(recovery days ÷ grazing days + 1)
Total rotation area = paddock area × minimum paddocks
The whole-paddock ceiling is intentional. For example, 30 recovery days and 2 grazing days require 16 paddocks, giving a 32-day cycle and 30 days of recovery. Dimensions assume a simple rectangle with the selected length-to-width ratio. The perimeter result is geometric only; it does not estimate shared fence, lanes, gates, water lines, terrain, or materials.
Worked Example
For 30 cattle averaging 1,200 lb and eating 2.5% of live weight as pasture dry matter, daily herd demand is 900 lb DM. If pre-graze forage is 2,400 lb DM/acre, the target residual is 1,200 lb DM/acre, and harvest efficiency is 75%, usable forage is 900 lb DM/acre.
For a 2-day occupation, the target paddock is 2 acres. A 30-day recovery target requires 16 paddocks, so the complete rotation needs 32 grazeable acres under those assumptions. Actual allocations should be adjusted from pasture observations.
Reading the Results
| Result | What it means | Field check |
|---|---|---|
| Paddock size | Area allocated to the full herd for one occupation. | Move earlier if the residual is reached early; add area if intake or residual is short. |
| Minimum paddocks | Whole paddocks needed to meet or exceed the target calendar recovery. | Return only when plants have actually recovered. |
| Stock density | Animals present per allocated area, not a season-long stocking rate. | Check trampling, manure distribution, access, and behavior. |
| Area margin | Difference between entered grazeable pasture and the calculated complete rotation. | Keep contingency for slow growth, drought, mud, and uneven production. |
Pasture Rotation FAQ
How is rotational grazing paddock size calculated?
Herd dry-matter demand for the planned grazing period is divided by usable forage dry matter per acre or hectare. Usable forage is the difference between pre-graze forage mass and the target post-graze residual, multiplied by harvest efficiency.
How many paddocks are needed for rotational grazing?
The planning formula is recovery days divided by grazing days, plus one. The result is rounded up to a whole paddock so the planned recovery time is met or exceeded.
Why are target residual and harvest efficiency separate?
Residual protects the forage left after grazing. Harvest efficiency accounts for forage above that residual that is trampled, fouled, rejected, or otherwise not eaten. Keeping them separate makes the forage budget easier to audit.
What dry-matter intake percentage should I use?
Use a value appropriate to species, body weight, production stage, forage quality, and supplementation. A generic starting estimate cannot replace a livestock nutrition plan or local extension guidance.
Should I use pasture height or forage dry matter?
Use dry matter per acre or hectare when possible. Height can be converted to forage mass only with a locally calibrated grazing stick, plate meter, or species-specific relationship.
Does the calculated paddock count stay fixed all season?
No. Plant recovery and forage growth change with species, weather, soil moisture, fertility, and season. Adjust the active rotation, use temporary fencing, skip fast-growing paddocks, or provide a sacrifice area when monitoring shows the plan no longer fits.
Are pasture and herd inputs stored?
No. Calculations run locally in the browser, and this planner does not send or store the values entered into the tool.
Calculation References
- Penn State Extension: Four Steps to Rotational Grazing — paddock sizing from available pasture and herd demand, plus the recovery-period paddock-count formula.
- USDA NRCS: Pasture and Range Health Planning Technical Note — grazing-cycle and paddock-number relationship, recovery planning, and stock-density concepts.
- Oklahoma State University Extension: Stocking Rate — dry-matter supply, utilization, and daily forage-demand calculations.
Planning Limits
This is a forage-allocation estimate, not a grazing prescription. It assumes forage and live-weight inputs represent the grazing group and every planned paddock. It does not model selective grazing, poisonous plants, nutrient balance, water availability, shade, slope, soil damage, animal health, variable paddock production, drought, or legal and environmental requirements. Monitor plants and animals, maintain a contingency plan, and use local extension, NRCS, veterinary, and nutrition guidance where appropriate.