Missouri's Maurice Davis, retired Natural Resources Conservation Service (NRCS) state grassland conservationist, says the most frequent grazing mistake he saw during his career was producers allowing livestock to graze pastures too short.
Grazing a pasture to the ground, either because it's overstocked or the livestock have been left there too long, "does not leave enough residual plant material to carry on photosynthesis," he says.
As a result, Davis says root growth stoppage begins. "That means top growth of the plant also stops," he adds. Specifically, research shows when up to 50% of a plant's leaf volume is removed, root growth stoppage is about 2-4%. If 60% of the leaf volume is removed, root growth stoppage escalates to about 50%. At 80% removal, the roots have no regrowth.
To prevent overgrazing, he suggests producers monitor when to move animals to new pasture based on residual plant material — the green stuff left after grazing.
Davis and most range managers advocate the rule, "take half and leave half," meaning once the forage has been grazed to about half its volume across the pasture, cattle should be moved to a new pasture.Pastures can be grazed shorter, but then the rest period required for recovery becomes longer, Davis says. As a guideline on introduced pastures, he says plants should not be grazed below a minimum of 3 in.