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Summer heat can be dangerous for horses, resulting in dehydration, lethargy, and general malaise. Severe heat stress can cause diarrhea, or even colic. But owners can take important steps to keep horses safe and comfortable during the hot days ahead.

In a release issued June 19, Janet Johnston, DVM, Dipl. ACVIM, ACVS, an emergency critical care veterinarian at University of Pennsylvania School of Veterinary Medicine's New Bolton Center, suggested the following ten tips to keep your horse comfortable and safe in the summer heat.

1. Choose cooler turnout times. If your horse has a stall but is turned out for part of the day, provide turnout during the cooler hours. Overnight is ideal, but if that's not possible, turnout as early as possible during the day.

2. Provide shade. If your horse lives outdoors or if he must be outside during the day, provide relief from the sun. A run-in shed is best. Trees are a source of shade, but as the sun moves, so will the shade; ensure that, regardless of the time of day, the trees are offering shade.

3. Move the air. Fans are a great way to help keep the air moving in the barn, but use them wisely. Always ensure that your horse can't get a hold of cords and plugs.

4. Mist your horse. If you are fortunate enough to have a misting system for your horse, use it. As moisture is absorbed from your horse’s skin, it will take away some of the heat. Frequent mistings are far more effective than a single dousing with a hose.

5. Provide fresh, cool water. Make sure your horse has plenty of fresh, cool water. A bucket hanging on a pasture fence will get warm, and the water will no longer be appealing. Left long enough, the water will also become stagnant and unhealthy. If you are providing clean, cool water and your horse doesn’t seem to be drinking enough, encourage him to consume water by providing a salt block, or even by misting hay with salt water.

6. Offer electrolytes. If your horse is sweating a great deal, an electrolyte supplement or water laced with electrolytes can help keep his body in balance. Whenever you offer electrolytes, however, be sure to offer fresh water, as well. Too many electrolytes can be harmful.

7. Slow down the work. Don’t think that because your horse has been working intensely at 1 p.m. every day that he can take the heat when the temperature tops 90°. If you have to work your horse in the heat, lighten the work or spread it out over a couple of short sessions. This is especially important when the humidity is high, which can diminish the poor quality of the air your horse is breathing.

8. Stick to a schedule. Within the parameters of keeping him cool, try to stay as close as possible to his normal schedule. Too much change at one time can be an invitation for colic.

Consider using a fly sheet to help protect white or gray horses from sunburn.

Photo: Thinkstock

9. Avoid sunburn. Horses, especially white horses, can suffer from sunburn. Even those with white socks and blazes, pink noses, or hairless patches from scarring can be susceptible. Using a fly scrim can help. In addition, applying sunblock to small, particularly vulnerable areas can be effective. Staying out of the sun’s harmful rays will, of course, be best. (Also be aware: If a horse has excessive sunburn it could indicate a rare, underlying liver disease.)

10. Clip horses with longer hair coats. Clipping is important, especially for those with pituitary pars intermedia dysfunction (PPID, or equine Cushing's disease). While some coat can provide protection from the sun and insulation, a long, thick coat tends to hold heat and makes it difficult for the horse to cool down.