Tips for managing drought-stressed horse pastures
Here are 10 tips from University of Minnesota Extension equine specialist Krishona Martinson.
Recent dry weather has raised questions about how to manage horse pastures during drought.
According to University of Minnesota Extension equine specialist Krishona Martinson, here are some tips for managing drought-stressed cool-season grass pastures in the Midwest that can help ensure pasture longevity and maximize growth when rainfall comes.
Without moisture, pasture growth slows and pastures may even become dormant. Grazing or mowing below three inches and excessive hoof traffic can accelerate drought effects and slow regrowth once it rains.
Evaluate stocking density
Reduce horse-grazing pressure by limiting grazing time, grazing only a few horses versus the entire herd, using grazing muzzles and feeding hay.
Provide time for regrowth after rainfall
One rainfall event does not immediately improve a dry pasture because it can take several inches of rainfall to restore soil moisture. Regrowth should reach 6-8 inches before grazing resumes. While grazing regrowth before it reaches six inches may provide some forage, it is detrimental to pasture plants, can weaken root systems, and will reduce the long-term productivity of the pasture.
Some weeds are especially good at surviving in dry conditions and use scarce water resources. It is best to control weeds during wetter periods when weeds are actively growing. Always read the herbicide label prior to use. Ensure the product is labeled for pastures and follow all grazing restrictions and recommendations related to environmental conditions at the time of use.
Maintain pasture fertility
Fertilize pastures annually according to soil test results. Fertilizer is most effective when it is dissolved into the soil via rainfall. Therefore, owners should be ready to apply fertilizer when rainfall returns following a drought.
Dry pastures regrow more quickly when fertilizer, especially nitrogen, is applied prior to rainfall. You can apply fertilizers up until early September.
Planting warm-season (teff) or cool-season (winter wheat) annuals can provide emergency forage. Annuals effectively provide short-term forage for horses when planted between mid-August and early September.
However, in cases of extreme drought, annuals are not a good option as some rainfall is needed to support germination and plant growth.
Maintain and use a dry lot
Housing horses in a dry lot will help avoid overgrazing and provides an ideal place to feed hay.
Be aware of nonstructural carbohydrate (NSC) content
Cool-season grasses average 12 to 16% NSC during summer months. But NSC content can exceed 20% during dry periods. This is because grasses tend to accumulate NSC to help buffer the negative impacts of stress, including drought.
While elevated NSC concentrations may not negatively affect healthy horses, these levels are likely to cause issues in horses with a history of laminitis, obesity, Equine Metabolic Syndrome, and other diagnoses requiring a diet lower in NSC.
Know the risks associated with nitrate toxicity
The potential for nitrate toxicity, especially if grazing weedy pastures, warm-season grasses, or their early regrowth, is elevated during dry periods. A forage nitrate test can determine the risk for nitrate toxicity.
Horses should not consume forages with nitrate concentrations over 4,600 ppm.
Dry pastures tend to be sparse with shorter grasses, which can increase the likelihood of ingesting soil, especially sand, and parasites. Watch for signs of sand colic and ensure horses are current on deworming.
Finally, during dry conditions, it’s important that horse owners plan ahead with hay and forage alternatives. If pastures are negatively impacted by dry conditions, it's likely local hay supplies will be as well.
Calculating hay needs, communicating early and often with hay suppliers, and considering forage alternatives can help provide viable options and allow owners time to prepare for feeding horses during dry periods.