By Kentucky Equine Research Staff
In Arthur Conan Doyle’s The Hound of the Baskervilles, the renowned fictional detective Sherlock Holmes assesses the quality of a portrait by stating simply, “I know what is good when I see it.” For some horsemen, high-quality pasture may be viewed in the same way—difficult to describe but easy to identify.
What attributes separate high-quality pasture from middling or poor pasture? Some characteristics include species and growth stage of plants, density of desirable plants, weed population, and presence and extent of sacrificial areas. These barren areas are often found around feeders, waterers, or fencerows because of high traffic.
Pasture quality is often intrinsically linked to pasture care. Are soil tests conducted to inform owners how to fertilize? Are pastures mowed and dragged regularly? Are weed-control measures performed?
Kentucky Equine Research prompts horse owners to complete a detailed form when they request a ration evaluation. Every component of a horse’s diet must be depicted accurately. One question asks owners to describe their pastures in one of five ways: drylot, sparse, moderate, lush, or high in oxalates. By knowing the quality of pasture, especially the availability of forage, nutritionists can estimate potential intake levels and the nutrient contribution to the diet.
Drylot. A drylot is any area where horses are turned out and able to move around freely, but the area contains no forage. Drylots are often sand or gravel runs connected to a stall or turnout paddock. A drylot is ideal for horses that must consume carefully regulated diets such as easy keepers or those diagnosed with certain metabolic diseases. Horses with drylot turnout only will be entirely dependent on supplemental forage sources such as hay, chaff, forage cubes or pellets, or alternative fiber sources. If horses spend more than an hour or two in a drylot, forage should be provided to them.
Sparse pasture. Sparse pasture provides some forage for horses, though quality may be poor. The forage may be overmature, which can be determined by the presence of thick stems and seedheads, or it may be yellowing or brown, as in the case of drought-stricken plants. Sparse pasture may be due to overgrazing, which often leads to a flush of weed growth. Sacrificial or loafing areas may start small but spread wider, giving weeds a chance to take a foothold. Sparse pasture may also be due to inappropriate management, such as infrequent mowing, inadequate weed control, or lack of fertilization. This pasture will not support optimal dry matter intake per day but may be appropriate to meet the needs of easy keepers.
Moderate pasture. Moderate pastures may have a mix of grasses interspersed with weeds. Pasture will be unevenly grazed but will have minimal bare spots. Plant height will typically be inconsistent. Moderate pasture generally does not have consistent care with some mowing and minimal or no fertilization. Like sparse pasture, moderate pasture will not support the maximum dry matter intake per day.
Lush pasture. Lush cool-season pasture contains thick stands of grasses with few or no bare areas and even distribution of grazing across the pasture with minimal weed proliferation. Plants are kept at a height of 6-10 inches by regular mowing. This pasture will support maximum rate of dry matter intake. Cool-season grasses grow best during cool, moist periods of the year, such as in spring or autumn. They thrive in the temperature range of 59-77° F. Common cool season grasses include tall fescue, orchardgrass, ryegrass, Kentucky bluegrass, and bromegrass. Warm-season grasses grow best during warm periods of the year, flourishing when temperatures are in the range of 86-95° F. Bermudagrass and bahiagrass are typical warm-season grasses. When grasses are faced with temperatures outside of their ideal range, growth may slow considerably, decreasing yield.
Legumes such as clover, lespedeza, and alfalfa are most often used in pastures as components of mixes with grasses. Both grasses and legumes provide essential nutrients to horses, though legumes will convey more energy and protein as well as certain minerals.
The fifth category, high-oxalate pastures, pertains primarily to horse owners in tropical regions. Oxalates bind calcium in the gastrointestinal tract of the horse, thereby prohibiting its uptake into the bloodstream and its subsequent use throughout the body. Ingestion of these plants is typically not an issue unless they represent a large fraction of available forage or if oxalate-laden plants are more palatable than other species in the pasture landscape. Kikuyu, buffel, pangola, and green panic grasses all are potentially dangerous because of high oxalate levels.
Reprinted courtesy of Kentucky Equine Research. Kentucky Equine Research is an international equine nutrition, research, and consultation company serving horse owners and the feed industry. Our goals are to advance the industry's knowledge of equine nutrition and exercise physiology, apply that knowledge to produce healthier, more athletic horses, and support the nutritional care of all horses throughout their lives. Learn more at https://ker.com.
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