Grasses are capable of regeneration in spite of continuous grazing by cattle suggest the reason for it?

Grasses' growth points (apical meristems) are at ground level, at a point where animals like cattle are unable to rip up. Tillers also start at ground level, and will sprout when the parent plant seneces or dies off. Tillers are developed as the parent plant reaches maturity, and when the next growing season begins or the time begins for grasses to regrow after being grazed.