It is tempting to turn horses out into spring pastures at the first sight of green grass, especially after a long winter. However, spring grazing should be introduced slowly and delayed until grasses reach 6 to 8 inches in height to optimize both the health of the horse and pasture.
When horse pastures reach 6 to 8 inches, begin grazing for 15 minutes, increasing the grazing time each day by 15 minutes until 4 to 5 hours of consecutive grazing is reached. After that, unrestricted or continuous grazing can resume.
It is also recommended to feed horses their normal hay diet before turning them out to pasture during the first several grazing events of the year (along with the time restrictions). This strategy should help avoid rapid intake of pasture grasses.
Even though hay and pasture are both forms of forages, there are significant differences. Dried hay is approximately 15% moisture compared to fresh pasture that is 85% moisture. The horse is a hind gut, fermenting herbivore that relies extensively on the microbes present in its gastrointestinal tract to be able to process forages. A gradual change from one feedstuff to another provides enough time for the microbial populations to adjust.
Pasture grasses need sufficient growth before grazing is allowed. Photosynthesis (the process of converting solar energy to chemical energy) occurs mainly within the leaves of plants. If the leaves are grazed too early (prior to 6 inches tall) or too often, plants can lose vigor, competitiveness, and root structure due to the lack of photosynthetic ability. This will lead to eventual die back and overgrazed areas being replaced by undesirable plant species or weeds.
Grazing should cease when forages have been grazed down to 3 to 4 inches. At this time, move horses to another paddock or a dry lot. Grazing can resume when grasses regrow to 6 to 8 inches.
On average, 2 to 3 acres of well-managed pasture can provide the forage needs for one horse from spring to fall.
It is critical to slowly introduce horses to spring pastures. When horse pastures reach 6 to 8 inches, begin grazing for 15 minutes, increasing the grazing time by 15 minutes each day until 4 to 5 hours of consecutive grazing is reached. Following this recommendation will help ensure both horse and pasture health.