I heard this second hand:

In the North West various crops have required burning of stubble to ensure good crops, e.g. Blue Grass. Environmental regulations prevent burning more and more. In recent years farmers contract with traveling goat herders that bring about 200 goats to a stubble field and clear the field in a few days. A hand full of herding dogs, under the control of a few herders, control the goats as they eat their way down to almost bare earth. One Presta Carnaro roams the herd on guard, the protector. This is not as cheap as burning but apparently as effective.