Pasture PathPaddock calculator for rotational grazing
How many paddocks a rotation needs, and how big to make them, from the rest you want each one to get and the herd you are feeding.
- Total grazing area
- 37.2 acres
- Full rotation takes
- 33 days
- The group eats per day
- 676 lb
- Taken from each paddock
- 2,028 lb
Paddocks = rest days ÷ days grazed (rounded up) + one per group. Paddock size = what the group eats during its stay ÷ what you let it take from each acre.
An estimate from the numbers you entered. Growth slows through the season, so plan for the slow months, not the fast ones.
The two sums behind a rotation
How many paddocks. While one paddock is being grazed, all the others are resting. So the number you need is the rest period divided by the length of each stay, plus the one the animals are in. Thirty days of rest with three-day stays is ten resting paddocks and one being grazed: eleven.
How big. A paddock has to hold enough feed for the stay. Twenty 1,300 lb pairs eating 2.6% of their weight take about 676 lb of dry matter a day, or about 2,030 lb over three days. If you turn them in on 1,200 lb per acre and mean to take half of it, that is about 3.4 acres.
Growth is not steady. A rotation sized for June will be too tight in August. Many graziers size for the slow part of the season and take a hay cut, or skip paddocks, when grass gets ahead of them.
From a sum to a fence line
Once you know the size, the question is where the lines go: around the water, along the creek, avoiding the bush. Draw the paddocks on satellite imagery in Pasture Path's farm map and it measures each one as you go, so you can keep adjusting until the acres come out right.
About paddocks and rest
How many paddocks do I need for rotational grazing?
Divide the rest each paddock needs by the days the herd spends in one, round up, and add one paddock for each group being grazed. With 30 days of rest and 3-day stays, one herd needs 11 paddocks. Longer stays mean fewer paddocks; longer rest means more.
How big should each paddock be?
Big enough to feed the group for its stay. Work out what the group eats per day (head × weight × intake), multiply by the days it stays, and divide by the forage you are prepared to take from each acre. The calculator does exactly that.
How long should a paddock rest?
Long enough for the grass to regrow to grazing height, which changes through the year: often a few weeks during fast spring growth and considerably longer in summer heat, in drought and in fall. Plan paddock numbers around the long rest, and move faster when growth is fast.
How long should animals stay in one paddock?
As short as you can manage. After a few days plants begin to regrow, and animals left in place graze that regrowth, which is what wears a pasture out. Many graziers aim for stays of one to five days.
Can temporary fence count as paddocks?
Yes. A paddock is whatever the animals are confined to for a stay, whether that is permanent fence or a polywire moved every day. In Pasture Path you can draw either kind on your map and see how long each has rested.
More tools, and the app they come from
Stocking rate calculator
How many animals a pasture can carry for a season, in AUMs and in head.
Acreage calculator
Draw a field on satellite imagery and read off its acres and fence length.
Rotational grazing in Pasture Path
Keep the rotation on your own map: one-tap moves, rest days on every paddock, the next one suggested.
Keep the rotation on your own map
Pasture Path tracks which paddock each group is on, how long every paddock has rested and which is ready next. Free in early access.