Today, when I woke up at 6:30, it was -10 and felt like -27. When I checked again at 8:30, it had warmed up to -8. In preparation for the cold snap (the winter so far has been mild) we bundled the horses up in their winter jackets.
Up until now, we’ve been leaving them naked for the most part and I’ve been surprised by how well they’ve been doing with just their fur. Although many horse owners blanket as soon as the air gets nippy, horses are much better able to withstand cold than heat. An article in The Horse, interviewed Amy Gill of Equine Marketing and Consulting in Versailles, Ky. who explained how cold it needs to be before horses have difficulty staying warm:
The critical temperature below which horses must begin to use calories to maintain body core temperature, called thermoregulation, is -10° C (14 °F). When the temperature is above 14° F, there is no increase in energy requirement needed to maintain body temperature in a maintenance level horse which is not gestating, lactating, growing, or in work and is not subject to windy or wet weather. This information applies to the maintenance level horse turned out for the winter.
The 500 kg (1,100 lb) horse will experience a 35% increase in metabolic rate and heat production to stay warm once the temperature falls below -10° C (14° F). For every degree centigrade the temperature drops below this level, one must increase the digestive energy, or calories, by 2.5%. For that 500 kg horse, you would increase his caloric intake by .408 Mcal of digestible energy daily. This horse needs 16.4 Mcal daily for maintenance, and you are adding about one-half a Mcal per every one-half degree drop in temperature.
Obviously, we have reached that point here in Massachusetts.
By Thursday, Freedom, at least, made it clear that he was cold. He was grouchy. And unhappy. A blanket and some extra hay cheered him up immensely. But hay alone didn’t do the trick.
Figuring it was going to get even colder, I added an extra layer on Friday morning. They all made it through the really cold night and when I fed tonight, they were still warm. Although I think that Freedom, like I, is seriously considering Aiken as our next winter destination.