One of our many astute readers kindly pointed out errors in in the FHOTD post on pastures
"There is no hard and fast rule of thumb about how many acres of pasture a horse needs."
Maybe if you are not concerned with your horse's parasite load and the quality of the grazing. A call to your local agriculture branch will give you the horse to acre ratio for your area. Information is available online, as well as other essential pasture considerations, from your Provincial or State agency.
A soil analysis is a good beginning in assessing the quality of your pasture. Many areas lack nutrient which can effect the quality the pasture grass. For example, in areas low in selenium a fertilizer that addresses the deficiency is recommended for pasture land. Another option would be feed a selenium supplement to your horse.
A second consideration is the type of grasses which constitutes the pasture. If these grasses are not of the correct type or ratio it can be detrimental to your horses health. A weedy pasture or an over grazed pasture will be less nutritious than a pasture that has been well cared for.
Fugly's notion of putting horses in an alfalfa pasture is not the best idea. A horses diet needs to be balanced and the high calcium content, without the matching phosphorus content, of alfalfa can cause problems.
To maintain the pasture it is essential, unless the pasture is large enough, that it be rotated. This will allow the grass to recover and the parasites to die off. Manure can contaminant the pasture two to three feet around it. Over the course of month much of the pasture can become contaminated with parasites.
"By the way, large acreages can present their own problems too! It becomes a lot harder to check horses daily for injuries, maintain fence, watch for the presence of animal holes or other hazards, etc. And of course it is much harder to secure from thieves. I know a lot of people with large properties who keep a smaller sacrifice area down by the barn, and use it as a catch pen. They call the horses down at least once a day and lock them in, usually with a bribe of a few handfuls of grain or some tasty hay that is even more appealing than the pasture. I’ve worked at a place where they ring a bell and everyone comes running – a huge convenience when it is time to ride and you don’t want to hike out over 100 acres looking for your mount, who may otherwise very well toss his head, laugh at you and head for the hills!"
Ridiculous! Train your horses to come when they are called, it's not difficult. Trooper is on 250 acres and comes when he's called. No I don't have to chase him over half the country side to catch him. Large pastures can be checked you just have to get off your butt to do it.