Grazing Days Calculator
Work out how many days the herd has left in this paddock before it is time to move.
Your numbers
Grazing left before the residual target is hit
8.6 days of grazing
- Available forage in the paddock
- 16,800 lb DM
- Herd eats per day
- 1,950 lb DM
- Stock density
- 3,750 lb live weight/acre
- 8.6 days exceeds the 7-day maximum graze period. Split this paddock and move sooner, or cattle will regraze regrowth.
- Convention: intake scales linearly with body weight, the same convention used in state extension AUE tables and across every Agrilot grazing tool. Energy-based intake models such as NASEM scale by metabolic weight instead, and will differ modestly for herds well above or below a 1,000 lb mature weight.
- Walk the paddock before the calculated date — move on the residual you can see, not the number on the screen.
Show the math
- Forage above residual2,400 − 1,000 = 1,400 lb DM/acre
- Actually harvested per acre1,400 × 60% = 840 lb DM/acre
- Paddock total840 lb/acre × 20.0 acres = 16,800 lb DM
- Herd daily intake60 head × 1,250 lb × 2.6% = 1,950 lb DM/day
- Grazing days16,800 ÷ 1,950 = 8.6 days
Assumptions this calculator used
Nothing here is hidden. Change any figure you have better local data for.
2.5-2.6% for a lactating cow; drop to 2.0% for dry cows on mature forage. Source: NASEM/NRC Nutrient Requirements of Beef Cattle, 8th rev. ed..
% of body weight- 7 days
Beyond this, cattle begin regrazing regrowth on plants they already bit. Source: USDA-NRCS prescribed grazing standard (Code 528).
How to calculate grazing days
A grazing-day estimate is short-term forage budgeting. You count only the forage above the residual you have promised to leave, subtract what gets trampled, and divide by what the herd eats in a day.
Days = ((standing lb DM − residual lb DM) × utilization × acres) ÷ (head × weight × intake %)
Worked example
A 20-acre paddock carrying 2,400 lb DM/acre, with a 1,000 lb residual target, leaves 1,400 lb/acre available. At 60% utilization that is 840 lb/acre, or 16,800 lb across the paddock. Sixty head averaging 1,250 lb and eating 2.6% of body weight consume 1,950 lb a day. That is about 8.6 days — past the 7-day maximum, so this paddock should be split in two.
Common mistakes
- Counting all the standing forage. The bottom three inches is next month's regrowth, not this week's feed.
- Leaving the herd in until the grass is gone. The last two days in a paddock are the most expensive grazing on the ranch, in recovery time.
- Using cow weight instead of total herd weight. Sixty 550 lb calves are another 33,000 lb of intake.
- Assuming spring numbers hold in midsummer. Regrowth is not linear; recheck standing forage every rotation.
Typical grazing season length by state
Approximate number of days per year cattle can be maintained on standing or stockpiled forage without full hay feeding. Elevation, soil type and forage species shift these by two to four weeks.
| State / area | Typical grazing days | Main forage base | Hay-feeding days |
|---|---|---|---|
| Florida / south Texas | 330-365 | Bahiagrass, native range | 0-35 |
| Georgia, Alabama, Mississippi | 270-300 | Bermuda + winter annuals | 65-95 |
| Arkansas, Tennessee, Kentucky | 240-280 | Fescue, bermuda | 85-125 |
| Missouri, Oklahoma | 230-260 | Fescue, native warm-season | 105-135 |
| Kansas, Nebraska | 200-240 | Native prairie, brome | 125-165 |
| Iowa, Illinois, Indiana | 190-220 | Cool-season pasture | 145-175 |
| Virginia, Pennsylvania, New York | 180-215 | Orchardgrass, fescue | 150-185 |
| Colorado, Wyoming, Montana | 150-200 | Native range, meadow | 165-215 |
| North & South Dakota | 150-180 | Mixed-grass prairie | 185-215 |
| Minnesota, Wisconsin, Michigan | 160-190 | Cool-season pasture | 175-205 |
Calculators to run next
- Forage Yield CalculatorRun this first — every other grazing number depends on pounds of dry matter per acre.
- Paddock Size CalculatorUse when you are subdividing ground and need acres per break and paddock count.
- Pasture Rest Period CalculatorUse when regrowth is falling short and the rotation needs to slow down.
- Acreage CalculatorUse when you need the acreage of an odd-shaped field before any forage math.
- Stocking Rate CalculatorStart here when the question is how many cows the whole place will run for a season.
- Animal Unit Equivalent CalculatorUse when the herd is mixed, so one number stands in for every class on the place.
Guides that use this calculator
- How Many Cows Per Acre: Working Out Stocking Rate HonestlyCows per acre is an output, not an input. Here is the dry matter arithmetic behind it, the utilization rate most people get wrong, and honest numbers by region.
Questions ranchers ask
How many days of grazing do I have left in this paddock?
Take the standing forage above your residual target, multiply by acres and by your utilization rate, then divide by what the herd eats in a day. This calculator does exactly that and reports the move date in days. Anything past about 5 to 7 days in one paddock and cattle start regrazing fresh regrowth, which sets back recovery.
What residual height should I leave behind?
Rule of thumb: take half, leave half. For tall-growing forages like fescue, orchardgrass or big bluestem, stop grazing at 3 to 4 inches. For bermudagrass and other sod-formers, 2 to 3 inches. For native shortgrass prairie, leave 2 inches. Residual is the solar panel that regrows the pasture — grazing it off is what turns a two-week rest into a six-week rest.
Why should a graze period be short?
A grass plant starts regrowing within three days of being bitten. If cattle are still in the paddock on day 10, they will find and eat that tender regrowth, draining the root reserves twice from the same plant. Three days or fewer is ideal, seven is a workable maximum, and season-long continuous grazing is the opposite of this principle.
Do I include the calves in the herd weight?
Yes, once calves are past about three months and grazing on their own. A simple way is to enter total herd live weight — every animal on the paddock, calves included — since intake tracks body weight much more closely than headcount.
How much does trampling cost me?
At normal stock density, 15% to 30% of the forage in a paddock is trampled, fouled or bedded on rather than eaten. The utilization figure in this calculator already nets that out. Higher stock density concentrates trampling but shortens exposure, which is why mob grazers can reach 60% utilization while a set-stocked pasture manages 30%.
What if the paddock is regrowing while cattle are in it?
In peak spring growth, a paddock can add 60 to 100 lb DM per acre per day, which genuinely extends the grazing period. This calculator ignores that on purpose — during a short 1 to 5 day graze period the addition is small, and counting on it in July, when growth may be zero, is how pastures get overgrazed.
How do I measure standing forage without clipping samples?
A grazing stick or plate meter calibrated to your forage type is close enough for a move decision. As a rough guide, well-managed cool-season pasture carries about 250 to 350 lb DM per acre per inch of height above residual. Our forage yield calculator converts a hoop clipping or a height reading into pounds per acre.
Should I plan the rotation around days or around residual?
Around residual. Days are a forecast; residual is what you can see. Use the calculated days to plan labor and water, then walk the paddock and move when the residual target is hit, whether that is two days early or two days late.
Running out of grazing days sooner than you planned?
If the rotation is coming up short every year, the herd may be sized for a wetter decade. Agrilot's auctions run both directions — sell the cows that no longer fit the forage base, or buy replacements timed to the season you actually graze.