Cassie W. LeMaster, Area Agent and Equine Extension Coordinator
Horses evolved as grazing animals, well adapted to eating high-quality grasses and forages; therefore, forages should be the foundation of any horse’s nutrition program. Horses will consume approximately 2 percent of their body weight per day in forage dry-matter. If the major nutrient source is pasture, a 1000-pound horse will collectively consume and waste approximately 3 tons on average of forage dry matter during a 6-month grazing season. Alternatively, you can imagine what these forage-consuming machines will do to your feed budget if all of this was to be provided in the form of hay. Luckily, many of our favorite “pasture ornaments” and “weekend warriors” can be maintained on quality pasture alone. During the growing season, hay and concentrate feeding can be drastically reduced, and even eliminated, in these horses with access to productive pastures. South Carolina has a good climate for growing forages nearly year-round, but management is key.
Most horse farm layouts allow the herd uninhibited access their entire pasture or paddock, which is termed ‘continuous’ grazing. When continuously grazed, the horse’s grazing behavior often makes managing our pasture forage quality and utilization more difficult. Since horses prefer young immature plants, when given a choice, they repeatedly return to the same areas of the pasture to graze the tender re-growth. This behavior, and the avoidance of elimination areas, create areas of overgrazed ‘lawns’ and under-utilized taller ‘roughs’. These overgrazed areas then reveal bare soil for weeds to move in and take over, further reducing our pasture productivity.
Rotational Grazing: A tool in pasture management
While it does require more management to set up, rotational grazing can result in greater forage growth and overall productivity, which means feeding less, or ideally no hay, during the growing season. A rotational grazing system is usually composed of a drylot or sacrifice lot with several pastures attached (recommended drylot space is 400-1,000 square feet per horse). Rotational grazing systems work because they give each pasture an opportunity to rest and re-grow.
By managing the grazing system, we require the horses to be less selective, forcing them to graze all areas of the pasture before the roughs reach unwanted maturity levels. We also protect the re-growth from being grazed through the creation of rest periods. Additionally, if pastures are mowed after each grazing rotation, similar plant growth, maturity level, and therefore grazing preference, can further be maintained. Dragging manure piles during hot dry weather helps kill parasite eggs and distributes the nutrients across a larger area, and thereby eliminating the areas your horses find undesirable to graze.
Under typical rotational grazing systems, all of the horses in a herd will be allowed to graze the first pasture when the grass is at optimum height (6-8 inches for fescue and about 4 inches for bermuda/bahia) and are removed when grass is grazed down to acceptable levels. Once grazed down, the horses will be moved to the next pasture. It is important not to let the pasture become overgrazed, otherwise the overall stand will be weakened, damaging root reserves and increasing re-growth time. The length of time spent grazing each pasture will be determined by forage growth and grazing intensity, not the calendar. Fescue may need as little as 2 weeks of rest during spring, and as many as 5 to 7 weeks during hot, dry weather. In spring, when pasture growth exceeds consumption, speed up the rotation or cut the excess for hay. If pasture re-growth is not quick enough for the rotation, utilize your sacrifice area for turnout and provide hay until the next pasture has sufficient growth for grazing.
Avoid turning horses out on pasture during rainy seasons as the tearing action of the horses’ hooves rip up grass and create muddy areas. In this case, it is best to house horses in the dry lot until conditions improve. As with any change in feed or feeding routine, it is necessary to gradually adapt your horse(s) to new, lush pasture, particularly in the spring. Nutritionists recommend starting with 15 minutes of grazing and increasing the grazing time by 15 minutes each day until 5 hours of grazing is reached. At that time, it is safe to allow your horse 24-hour access to the pasture, if necessary.
