Horses should be preconditioned by gradual increases in the amount of energy fed per day. Increases in hay are much more readily tolerated by horses. If the cold spell only lasts one to two days, alterations in grain may not be needed. However, if the cold spell is over an extended period of time, adjustments may gradually be made. Preconditioning horses before the onset of cold temperatures helps to reduce the effect of cold weather on nutritional needs.
Fat cover acts as an insulator and provides energy reserves during stress.
It may be difficult for horses to increase body condition during extremely cold weather. Additionally, during long bouts of freezing temperatures, most horses will experience some loss of body condition, no matter how well they are fed. Water Requirements Horses will tend to reduce their water intake as temperatures fall. This reduced water intake, combined with increased forage consumption can lead to a greater incidence of impaction and colic. Water should be maintained between 45 and 65 degrees F and any ice crystals should be removed.