You might have heard to give your horse a warm bran mash when the temperature drops to prevent colic in horses. The thought process is that the warm bran will keep the horse hydrated and the wheat bran will help keep things moving well in his gut by having a laxative effect. This is an age old tradition that a lot of horse men have lived by but it goes against all the research saying horses don’t do well when their diet is changed quickly.
Horses thrive on a consistent diet and if it needs to be changed it needs to be done slowly over a week or two. The reason being that horses have digestive enzymes just like people do to help digest their food. Those enzymes get used to the food they eat and changing it rapidly does not give the horse’s enzymes to adapt to the new food and the horse cannot digest it as well.
Instead of giving a bran mash each time it gets cold try wetting down his regular grain with warm water. You can also add some apple or carrot peelings to make it more appetizing and some salt or electrolytes to help with hydration. This will help keep him warm and hydrated and still feel like you are going the extra mile for your horse!