Pasture Management for Horses
How Much Pasture?
How much grazing does a horse need? The answer, sadly, varies. In good conditions such as northern Europe or, say, Maryland, then you can get away with as little as 1 acre a head - and ponies may have to be on restricted grazing. In Texas or Arizona, you might need as much as 5 acres. In most places, you're looking at somewhere between 1 and 3 acres a horse.
If you have less than that, your horses will have to spend a fair amount of time inside or in a "sacrifice area" so the pasture will not be overgrazed, and will need to be fed hay. (At higher acreage, you can often cut hay to a minimum during the spring and summer). Rotating pasture can help manage smaller acreage.
The ideal lifestyle for a horse is in a good-sized field unless being worked, but not all of us can give our horse's that. At least some turnout, though, helps a horse's mental health considerably.
A "horse sick" pasture is a sad site. Much of the ground is mud. The rest is full of tough, unpleasant-looking weeds.
Many people give the simplistic explanation that it's caused by manure and the solution is to pick up the manure. Actually, you're better off breaking up manure piles and spreading them out - horse manure is good fertilizer and horses tend to have a "toilet" area they use, which can then become a mess of manure and mud. (This is caused by the fact that in the wild horses would roam a much larger area and not re-use their "toilets" that often).
The real cause of "horse sickness" is the limitations of the equine digestive system. Horses are picky eaters, because they are not as efficient at digesting tough plants as ruminants. They tend to eat up the plants they like - then the plants they don't like take over.
The cure? One possibility is to mow or hand-remove plants the horses aren't eating. (Any poisonous plants, such as ragwort, should always be hand-removed - horses won't normally eat them, but do you want to take the risk?) Another cure is to co-graze goats. Goats actively favor all the stuff horses don't like and make great companions for a solo horse.
If you do decide to buy a goat or goats, do not buy an intact male (even if you intend to immediately geld it - get that done before its delivered). Billy goats smell almost as bad as skunks. Gelded males, called "wethers," make good pets, as do females. I recommend goats that have been de-horned. A good course of action is to contact the local 4-H group and ask who supplies goats for their projects. (I have a personal fondness for Nubian goats - no horns, floppy ears, and wonderful temperaments, but they might be a little large for smaller properties).
If not, then you will need to remove those plants yourself, mow any tough areas of grass, and remove manure from the "toilet" if there is one. If you have more manure than you need, then cultivate a relationship with the local gardening club.
A sacrifice area is a smaller pen in which horses can be kept when the pasture needs to be rested without having to be confined to the barn. The sacrifice area will end up muddy. (Some people put down bluestone footing in sacrifice areas to prevent that - while a relatively expensive option it can save vets' bills from horses slipping and lots of time spent grooming and cleaning boots).
The sacrifice area should be a minimum of 16 feet x 16 feet per horse, and ideally larger. If you are really short on space, you can use an outdoor arena as a sacrifice area. Take into account how hard your horses work and what kind of winters you get - although bear in mind horses don't feel the cold nearly as much as we do and on days when you might think they'd rather be tucked in the barn? You'd be wrong. (Although I have had horses actively ask to come in on cold days, too).
Ways to Preserve Grazing
Short of using a sacrifice area, there are other ways you can preserve your grazing:
1. Blanket horses when needed. If your horses are cold, they are eating more in order to keep warm. Paradoxically, a horse that has frost or ice on its back does not need to be rugged up - it's the ones on which the ice is melting that are cold. Don't start blanketing too early in the season, or you might compromise your horse's winter coat.
2. Do use supplemental feed. Horses on good pasture in the summer should not need hay, but if the pasture starts to look iffy or it's dry, then add hay - use your common sense. In extreme drought, pull the horses in to a sacrifice area and feed hay. This can get expensive, but it's better than your horses looking like coat racks.
3. Spread manure properly. Don't overapply - if you have too much, again, you can easily get rid of manure. You can also compost excess manure. In some areas you may not be allowed to spread manure - this often includes floodplains or intermittent waterways. If that is the case, then you probably want to compost your manure.
4. Be aware that you don't have to split pasture further to use rotational grazing. Hot tape or hot wire will serve fine. Rotational grazing means simply moving horses off a pasture as soon as it starts to look less than green and lush. You will eventually work out a pattern for the number of horses you have and the rate of growth of grass and plants in your area. If unsure, ask local horseowners.
5. Please bear in mind that many ponies and draft crosses need to have their grazing restricted. If you keep ponies, consider building a dry lot - a sacrifice area that has gone one step further and had all of the grass actively removed. A fat horse is just as bad as a skinny one.