Scientists, we understand, consider simplicity, elegance and beauty some of the earmarks of a correct hypothesis.
So with grazing.
Take dairy. Wendell Berry, in one of the essays in his volume Home Economics, relates a conversation with an ecologically-sensitive Ohio farmer, in which that man states it as his opinion that a rough limit on the number of cows appropriate to a single dairy operation might be twenty-five. More than that, he says, and it’s not possible for the farmer really to see each animal, each day; not possible, then, to take adequate notice of her feet, the state of her hide, her appetite and affect, and so on. Our own experience would tend to confirm this.
Another measure of the proper size for a dairy could be taken by calculating how far a cow will willingly walk in order to be rid of her lactic burden, to enjoy her mouthful of alfalfa hay or rolled oats, her moment in the shade of the barn, and then back to her fresh paddock of forage.
One might also inquire how far the dairyman wants to walk twice round trip, twice a day, to drive the cows up to the dairy and then back out again to their grass.
We would reckon both distances to be not more than a quarter mile; ideally, less.
Locate your dairy centrally on a flat grass footprint and cast a circle around it, radius 1/4 mile, that’s about two-tenths of a square mile, or in the neighborhood of 70 acres. Mix this up a little with some hills and trees and call it fifty acres of grass, which is just about what we are grazing at the monastery right now, and in its present state of reclamation this has a carrying capacity, with six to twelve weeks of hay in the winter, of about twenty mixed Jerseys, cows, heifers, steers and weanlings; half that in lactating brood cows. Give us five more years of careful grazing and we might double it, making it twenty, which is pretty close to Mr. Berry’s friend’s twenty-five.
And twenty cows on grass milked even once a day would, if it were legal to sell the milk raw to those desiring it at even as little as $6/gallon, pay a couple a decent living to take care of that land and produce food on it. In fact, it used to do so.
Note that this elegance has been replaced by confinement barns, bulk tanks and manure lagoons, which latter looks an awful lot like a hypothesis that has gone bust.