Published August, 2012

You’ve seen it plenty of times: bare pasture grazed down to the nub. Who wouldn’t rather look out of the stable to see happy horses grazing on healthy pastures? One solution lies in rotational grazing, a simple management technique that subdivides pasture areas, which allows forage an opportunity to regrow after it's been grazed. By fencing off part of a pasture, horses can consume grass to a certain height before moving them to another “rested” part of the pasture. The grazed portion then has the opportunity to grow. Rotational grazing does involve more management than allowing your horses’ unfettered access to pasture areas, but the payoffs are worth the effort.

“If we set up our plan in such a way that we give forage plants enough time to grow back, we have more forage for the horses to utilize, which can then translate into reduced feed costs,” explained Bob Coleman, PhD, PAS, equine extension professor in the University of Kentucky’s Department of Animal Sciences. “The biggest benefit is that we are going to extend our grazing season by taking advantage of forage when it’s growing and then giving it a chance to come back.”

In addition, subdividing large pastures for rotation encourages more even grazing patterns, helping to reduce horses’ spot-grazing tendencies in which they choose and ultimately overgraze their favorite, highly palatable forage plants. “You can encourage them to be better consumers of all that’s there,” noted Coleman. “By moving the horses, you let those highly-selected species come back.” Horses also tend to overgraze pasture areas where they like to spend their time; rotating the horses off these areas reduces compaction issues, which also weaken forage plants.

A weakened pasture results when plants are not given the opportunity to replenish root and plant reserves. “A weak pasture stand is prime for weeds to take over,” Coleman remarked. “Grazing so hard you create bare ground is a wonderful opportunity for weeds to take over a pasture. They get sunlight and they don’t have any competition, causing weed issues.”

The nuts and bolts of rotational grazing are simple. The easiest approach is to subdivide your grazing areas with portable electric fencing based on the number of horses you have on your acreage. You should also plan your watering arrangement--this could involve either portable watering troughs or a permanent watering area around which the paddocks are subdivided. Coleman recommends creating a high-traffic pad around permanent water sources to eliminate mud and turf compaction (see “Creating Hardened Surfaces in High-Traffic Areas”).

A pasture is ready for grazing when available forage plants have reached a height of at least six to eight inches. This pasture can be grazed down to about four inches, at which point owners should move horses to another area. The time it takes for horses to graze down to four inches depends on the number of horses and the size of the paddock, but five to seven days is reasonable. Regrowth occurs 21-28 days later for cool season grasses under reasonable growing conditions. Environmental factors play a role as to when or even if you’ll move the horses onto a new pasture. For example, in spring when plant growth is active, horses can be rotated onto another section when grass is grazed to about six inches. This shorter grazing cycle will help you keep up with the growing pasture and hopefully reduce the amount of mowing needed to keep the pasture vegetative. On the other hand, when pastures are parched during hot, dry summer months or wet during rainy months, you should move the horses onto a ‘sacrifice paddock’ to protect pastures. At this point you must supplement the horses’ diet with hay.

Just as there’s not a set schedule as to when you rotate horses to another paddock, there is also not uniformity among pasture plants. “There will be areas of great selectivity, especially when there are mixed grass varieties,” Coleman explained. This means that some plants will be below four inches, while others might be taller. In this case you should move the horses out of that pasture and mow the grass to an even four inches to maintain a vegetative state.

Paying attention to your grazing areas is key to successful rotational grazing. “Horse owners need to be prepared to walk through their pastures. It takes management to make it work,” said Coleman. “Watch grazing patterns and pastures. Be observant.” Ultimately, pasture becomes healthier and forage becomes more palatable, making the extra effort worthwhile.

Freelance journalist Natalie DeFee Mendik is an American Horse Publications Editorial and Graphics Awards winner.