Older leaves are harvested and new ones receive more sunlight for faster growth. When the forage growth on the first pasture is grazed down, livestock are moved to the second one. While cattle graze the second pasture, forage is allowed to regrow on the first. While having two pastures instead of one is an improvement, flexibility and animal control both improve dramatically as pasture numbers are increased by installing additional cross fences. To install an intensive rotational grazing system, six pastures is a reasonable number to begin with.
Pasture size is influenced by the number of days of rest needed between successive grazings.
A rule of thumb is to allow each cool-season pasture such as orchardgrass and tall fescue a rest period of 15 days between grazings in the spring and fall. However, many producers graze them anyway. If tall fescue must be grazed in the summer, stands of the endophyte-free types are more likely to be killed. Endophyte-free varieties perform best when they are allowed to rest for 30 days before grazing again. Orchardgrass should have at least 3 inches of growth left standing throughout the summer.