Come the days of long shadows, when the sun lies low in the sky, jeweled leaves crumble and fade away, and the wind’s crispness hints of the cold, gray days on the way. The pasture dies down. It’s time to start getting extra fuel into your horses. Unless you live where temperatures are warm year-round, they need extra energy to stay warm through the winter. This is due to increased energy demands of cold weather and reduced nutrition in pasture.

Adjusting the Thermostat

Explains Karen E. Davison, PhD (equine nutrition), manager of equine technical service at Land O’Lakes Purina Feed, “All warm-blooded animals, including horses, have a critical temperature. This is the outside temperature below which a horse must produce extra heat to maintain its body temperature.” That temperature varies, depending upon the horse’s condition.

Davison says a mature horse in good flesh, where ribs cannot be seen, has a critical temperature around 30ºF during early winter. “After developing a winter coat and gaining 100 pounds, the critical temperature may be reduced to around 15ºF. It’s estimated that young horses, horses in thinner condition, and those that have been stabled and not developed a winter coat might have a critical temperature around 40°F. When wind or wet conditions are present, the critical temperatures will be higher, as well.”

A horse’s critical temperature also depends on cold extremes. Says Carey A. Williams, PhD (equine nutrition), the equine extension specialist at Rutgers University Equine Science Center, “It’s going to be different in northern Wisconsin as compared to Georgia in the winter months. As horses grow a winter coat, they are allowing their critical temperature to decrease, making them more comfortable at lower temperatures. So, zero degrees to a horse in Wisconsin will be the same as about 30 or 40