How many acres does it take to run a beef cow?

The best way to calculate the answer is to use AUM (Animal Unit Month) calculations. What that will be is estimate the amount of forage the cow will eat in a year, then, you will need to determine how many acres of forage it will take to produce that amount of forage.

Here are some websites that will help explain the system:$department/deptdocs.nsf/all/agdex1201

An example calculation follows: 1,000 lb cow weaning a 550 lb calf will need 13 AUM’s to sustain the grazing system 13 AUM time 780 lb/AUM equals 10,140 lb of forage, let’s estimate 35% harvest efficiency of the forage so the cow will need 10,140 / .35 = 28,971 lb of forage. If your pasture can produce 3 tons of forage/acre (6,000 lb/acre), then 28,971/6000=4.82 acres/cow Cross-fencing, supplemental feeding, winter hay, silage, etc. will adjust the number of acres.