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FurCalc

Livestock Stocking Rate Calculator — Animal Units per Acre

Calculate the carrying capacity of your pasture in Animal Unit Months (AUMs). Converts to beef cow-calf pairs, sheep, or goats.

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Carrying capacity
41beef cow-calf pairs
250 total AUMs · 2.4 acres per AU
Sheep equivalent
205
1 cow = 5 ewes
Goat equivalent
246
1 cow = 6 goats
Values are rough regional averages. Actual carrying capacity depends on rainfall, soil, pasture species, grazing management (rotational vs continuous) and fertility.

Frequently Asked Questions

What is an animal unit (AU)?

1 Animal Unit = 1,000 lb cow + calf consuming 26 lb dry forage/day (780 lb/month = 1 AUM). Other species: 1 horse = 1.25 AU, 1 sheep/ewe = 0.2 AU, 1 goat = 0.15 AU.

How many cattle per acre?

Depends heavily on region. Eastern irrigated pasture: 1 cow per 1–2 acres. Midwest: 1 per 3–5 acres. Semi-arid plains: 1 per 10–15 acres. Arid rangeland: 1 per 30–40+ acres.

What is rotational grazing and does it increase stocking rate?

Rotational grazing moves animals through small paddocks to give grass rest periods. Properly managed, it can increase carrying capacity 25–50 % vs continuous grazing by optimizing plant regrowth.

How do I calculate stocking rate for sheep or goats?

Multiply cattle rate by species AU ratio. 100 acres at 2.5 AUM/acre over 6 months supports 42 cows or 210 ewes or 280 goats.

Sources & References

  1. [1]
    Stocking Rate Basics — USDA NRCS
  2. [2]
    Range Stocking Rate Calculation — Oregon State Extension
  3. [3]

Common mistakes to avoid

  • Overstocking on dry years — 50-70% of your 2-year-average rate during drought prevents pasture damage.
  • Forgetting rest periods — continuous grazing on the same paddock kills desirable forage.
  • Ignoring forage quality — AUMs based on high-quality alfalfa differ from native grassland.

Pro tips

  • Rotational grazing with 4+ paddocks can DOUBLE effective stocking rate sustainably.
  • Keep a pasture calendar — note graze-in and graze-out dates, recovery time.
  • Consider a forage sample analysis once per season — costs $30 and prevents over/underfeeding.