Just as too many cooks spoil the broth, too many horses ruin a pasture. By following proper pasture management guidelines, you can optimize you acreage and your horse's nutrition. Planning and research before you turn your horse out to pasture should ensure success.
Estimates vary, but it is generally believed that each horse needs at least 1 1/2 acres of pasture, with the ideal amount being 2 acres allowed per grazing equine. A horse eats about 1 to 2 percent of its body weight each day in the form of pasture forage. That means a 1,000-pound horse eats up to 20 pounds of pasture forage each day.
There are a number of variables that enter into the 2-acre equation. Factors taken into consideration include the type of soil in the pasture; the varieties of grass; the quality of grass management; the amount of rest the grass has between cycles; how much time your horse spends on pasture throughout the year; the amount of food your horse needs to eat in 24 hours; and the amount of manure left in the field.
Just providing each horse with 2 acres doesn’t mean pastures don’t need management. Healthy forage plants and grasses are more productive if they’re allowed to rest and regrow between grazing. Augment grass growth by dividing a pasture into four separately fenced paddocks and rotating horses among them. Start with three or four weeks of rest per paddock during the summer months and adjust to allow more rest in the fall and less during the spring. A good rotational grazing plan does not negate the optimal 2-acres-per-horse stocking rate.
A commonly followed rule is to wait until grasses are between 6 and 10 inches long before you turn your horse out on the pasture. Horses should be rotated into another paddock when they have grazed the grass to a height of 3 to 4 inches. Continuous, close grazing can stunt grass regrowth and allow weeds to take hold.
The number of horses on a pasture, or stocking rate, should never exceed the amount the pasture can feed during the grass-growing seasons of spring and summer. Overstocking--grazing too many horses on too little pasture-presents a number of problems. It causes the pasture to deteriorate, making your horse unable to eat and providing you with nothing but a big, muddy, manure-filled mess. You also will have to buy horse food you could otherwise grow. An overstocking situation also provides an excellent environment for parasites to thrive and spread rapidly through your herd.