This is highly dependent on your location, forage quantity and quality, soil type, and terrain. Some areas may have a lower stocking rate than others. For instance, in Nevada, you may be lucky to be able to graze a cow-calf pair on 10 acres of pasture per week. In North Carolina, however, you will more than likely be able to graze a pair on 1 acre of pasture per month.
graze as in cows graze in the pasture
Around 80 days
Forage content will decrease until the rancher puts the cattle into another pasture to graze. Cattle will graze the pasture until a) they can't any more or b) the rancher sees that they've taken off enough and moves them to a fresh pasture.
If they have access to pasture every day, yes.
A horse is "turned out" into a paddock or pasture to graze.
A horse pasture should have enough space to graze as well as space to run. One horse is 1.5 AUs, so depending on your locality, pasture quality, time of year, etc., you could pasture one horse per 2 acres or more per month.
Grass lands or pasture areas.
A few weeks or until the grass is around 10 to 12 inches high.
If you have too much pasture and not enough animals to graze that pasture, you may end up with pasture that is overgrown or too far in a certain vegetative stage to be suitable for grazing for the animals you have. Thus taking hay off of that pasture will encourage grasses to regrow and thus allow your animals to graze that pasture while the others have a chance to rest--that is, once the grasses have grown back at a suitable height to be grazable again. Hay itself is also a good stand-by should pastures face drought or are too wet to have animals graze on. It allows animals to be fed in an alternate means while giving pastures to rest, to regrow and/or dry up, respectively.
Nomadic herders are limited to where they can graze their animals, and cannot manage pastures because there really is no such thing as a pasture. When the grass is not there, they have to move on; they can't stay in one place.
A pasture is where the horses graze. A paddock is an enclosed yard where they are exercised.
A field where animals graze is called a pasture. Most livestock live and graze in pastures when they are being bred or raised.