When I was at a horse show last weekend one of my friends informed me that her good halter mare had heat foundered on one of her front feet. Here in Michigan the majority of our summer has had above 90 degree days. I tried to offer her as much comfort as possible, having kept one of my horses sound for more then 20 years after he grass foundered.
Having owned and managed a foundered mare, you can image that I am always on high alert for signs of founder with the horse I now have.
Regardless, I now think one of our colts may also have a case of heat founder. I'm pretty surprised as he really showed no signs of stress during the hot periods of this summer. However, there really are no other causes for what's appearing to be a case of founder. He's not on grass, he hasn't been worked on hard surfaces, and he gets a very small amount of grain.
Please keep an eye on your horses. It's been a very hot, dry summer throughout the country. I can image that if I have a horse that has foundered from the heat, there are many more out there that are going to also show signs. For more information on heat founder go to http://www.ncaha.com/downloads/HOT%20WEATHER%20PRECAUTIONS%20FOR%20YOUR%20HORSE.pdf