Managing Horse Pasture During and After a Drought
During and right after a drought, NSC levels can be very high in these grasses and potentially dangerous for horses that cannot tolerate high NSC in their diets (conditions such as insulin resistance, Equine Metabolic Syndrome, laminitis/founder, etc). Even metabolically normal horses may have some digestive issues due to the rapid change in forage nutritional composition after a drought-breaking rain.
In addition, drought can cause some plants to accumulate nitrates. These are less of a concern to horses compared to cattle or other ruminants. However, if combined with high nitrates in drinking water and from other sources, then you could see toxicity symptoms like colic and diarrhea.
Lastly, toxic weeds may become more of a concern during drought because of the lack of other forage available. Weeds with deep tap roots will stay green longer than shallow-rooted forage grasses. Weeds may also
accumulate NSC during a drought, and if there are any toxic components, they may become more concentrated with less water in the plant. If horses cannot be removed from pastures during drought, they should be supplemented with hay while turned out to reduce the likelihood of them eating weeds.
Best Management Practices
Most horse farm owners in Pennsylvania do not irrigate their pastures, but if you do, a light irrigation every few weeks will keep the grass plants alive. Keeping the grass green and growing would take a lot of water, so delivering just enough to keep the roots alive (about ½ inch) will help the plants recover when rain returns.
To give your pasture the best shot at drought recovery, keep your horses in