While all crabgrasses are warm-season annuals that thrive in the heat, improved varieties developed over the last decade are much different than their garden variety cousins. They germinate rapidly, grow quickly, and offer large-leafed, high-quality summer forage. With this as impetus, researchers theorized that new varieties of crabgrass would pair well with cool-season grasses that have a tendency to grow slowly in summer months, often called “summer slump.” The grass mix would allow for more total forage to be produced throughout the growing season.
To test this theory, two 3.7-acre rotational grazing areas, each divided into six sections, were used—one as a control plot (mixed cool-season grasses) and one as an integrated plot (crabgrass and mixed cool-season grasses). Researchers designated three grazing periods based on time of year: early (mid-May to mid-July), slump (mid-July to mid-September), and late (mid-September to mid-November). Three horses grazed each area during every period. Horses moved from one section to another within a grazing area when sward height became too low. Forage samples were analyzed for nutrient content prior to each rotation. The body condition of all horses was tracked monthly using the Henneke system of 1 (emaciated) to 9 (extremely fat).
How did the two plots fare? Researchers calculated that the integrated system produced 20,000 pounds of forage over the growing season, whereas the control plot produced nearly 14,000 pounds of forage, indicating that implementation of “an integrated rotational grazing approach incorporating the warm-season annual crabgrass may offer production advantages when compared to a traditional cool-season grass rotational grazing system.” Of particular note, the crabgrass performed well during the summer slump period, from mid-July to mid-September, just as the researchers hoped.
Both systems provided adequate nutrition to horses, as evidenced by the fact that all horses maintained moderate body condition throughout the study.
Good-quality pasture is a cost-effective feedstuff for horses, so it is best to maintain grazing areas as well as possible, including appropriate reseeding, fertilization, and weed control measures. If reseeding, work with a pasture specialist to determine the best species for your region.
“Horses are engineered to be efficient grazers. Depending on the season and pasture quality, many horses can meet, even exceed, their energy requirements when allowed to graze,” explained Catherine Whitehouse, M.S., a nutritionist with Kentucky Equine Research. “Some horses, because of metabolic disease, may not be able to graze freely, but many, many can. Grazing also satisfies social and exercise needs.”
For horses fed all-forage diets, appropriate vitamin and mineral supplementation is often necessary for optimal well-being. Choose a high-quality supplement manufactured by a reputable company, recommended Whitehouse.
*Weinert-Nelson, J.R., W.A. Meyer, and C.A. Williams. 2021. Yield, nutrient composition, and horse condition in integrated crabgrass and cool-season grass rotational grazing pasture systems. Translational Animal Science 5:1-18.
Reprinted courtesy of Kentucky Equine Research. Visit ker.com for the latest in equine nutrition and management, and subscribe to Equinews to receive these articles directly.
