🌿 Cattle AUM Calculator
Calculate Animal Unit Months, stocking rate, and days of grazing for your pasture
✅ Grazing Management Results
Animal Unit Equivalents
| Animal Type | Weight | AUE | Animals per AUM |
|---|---|---|---|
| Cow-calf pair | 1,000 lb | 1.00 | 1.0 |
| Cow (dry) | 1,000 lb | 0.92 | 1.09 |
| Yearling steer | 600 lb | 0.60 | 1.67 |
| Yearling heifer | 600 lb | 0.60 | 1.67 |
| Bull | 1,500 lb | 1.50 | 0.67 |
| Horse | 1,000 lb | 1.25 | 0.80 |
| Sheep | ~100 lb | 0.20 | 5.0 |
| Goat | ~60 lb | 0.17 | 6.0 |
| Deer | ~100 lb | 0.17 | 6.0 |
Forage Production by Range Type
| Range Type / Condition | Lbs/Acre | AUMs/Acre | Notes |
|---|---|---|---|
| Degraded / poor condition | 400-600 | 0.18-0.26 | Overuse, low plant diversity |
| Native range, low production | 700-900 | 0.31-0.40 | Arid or semi-arid sites |
| Native range, medium | 1,200-1,800 | 0.53-0.79 | Moderate rainfall, mixed grass |
| Improved pasture, medium | 1,500-2,000 | 0.66-0.88 | Managed, fertilized |
| Improved pasture, high | 2,000-3,000 | 0.88-1.31 | Irrigated, heavy management |
| Alfalfa/grass mix | 3,000-4,500 | 1.31-1.97 | Top-end production |
Stocking Rate Guide
| AUMs/Acre | Range Condition | Management Recommendation |
|---|---|---|
| < 0.3 | Poor | Reduce stocking, allow rest for recovery |
| 0.3 - 0.6 | Fair | Moderate use, monitor forage closely |
| 0.6 - 1.0 | Good | Sustainable with rotational grazing |
| 1.0 - 1.5 | Excellent | Intensive management required |
| > 1.5 | Irrigated/improved | High input, continuous monitoring needed |
A cattle AUM, or Animal Unit Month, is a standard unit for estimating stocking rates on pastures and rangeland. Pasture and range managers use it to know how many animals a piece of land can feed under various conditions. You commonly use AUM to set sustainable stocking rates for pastures and rangeland especially in west regions
Standard animal unit matches one adult cow of 1000 pounds with its calf, or equal. One AUM shows the amount of dry forage that cow and her unweaned calf will eat during a month. That corresponds to around 780 pounds of air-dry forage with 90% dry matter.
Cattle AUM: How Many Cows a Pasture Can Feed
The consumption is calculated from daily input of 2.5% to 3% of body weight on a basis of dry matter. A cow-calf pair requires approximately one to 1.5 animal units per month.
Different animals do not match one to another. Adult bull values 1.3 AU. A yearling steer or heifer is 0.67 AU.
A weaned calf estimates 0.5 AU. Those numbers standardize the forage needs of various cattle types.
People talked about changing the calculation of AUM because few 1000-pound cows feed the ranches. Some pasture districts think to use average weight of fall cows to determine AUM ratios for every ranch. Proposed numbers pointed that a 1100 to 1200-pound cow with calf would match one AUM.
For every 100 pounds above 1200, you would add 0.1 AUM. Like this 1500-pound cow will estimate 1.3 AUM against the ratio.
Pasture plans and advice use AUM to estimate the carrying capacity of forage or pasture. It simplifies the standardizing of forage needs and available amounts. Herd size depends on climate, forage production, grazing method and cattle type.
For one typical AUM you require 0.8 to 1.5 acres of average rangeland per animal unit during a month, according to prodcutivity.
On federal ground under BLM, the rate for permit and lease holders are 1.35 dollars per AUM. You can buy grazing rights on BLM or Forest Service ground any time. West, price of one AUM grazing rights reach around 550 dollars.
Occasionally you point prices per acre or per month. Local agencies give AUM figures for their areas and help to estimate herd size according to observations of land response to animals.
