In some places not a lot. Some parts of the great plains have basically swapped Bison for cattle, and keep a vaguely similar ecosystem. However much more of thi

In some places not a lot. Some parts of the great plains have basically swapped Bison for cattle, and keep a vaguely similar ecosystem. However much more of this area is degraded due to have far too much cattle there too often. Bison used to graze and migrate, churning up the ground and adding fertilizer, and then letting things re-grow. Other livestock land is completely different from its 'wild state'. Cattle ranching in what used to be the Amazon. Sheep herding in European uplands, also takes place on land that used to be forest and temperate rain forest. Another feed in to the large percentage of land that goes towards livestock, is growing animal feed. The majority of cattle in the US is not just eating grass. It is eating crops that are grown specifically for feeding to cattle. So those fields of corn, that are then fed to cattle could also go back to their 'wild state'.