AAEP is the American Association of Equine Practitioner and they offer the following advice to prepare your horse for winter.
Diet: Digesting food is the horse's most effective source of heat. Cold weather increases the horse's calorie requirements; make sure to adjust quantity accordingly. Adjusting your horse over slowly to supplements or changes in feed is always best. Considering offering supplements with concentrates containing minerals and vitamins. These items can be purchased at either IFA or Cal Ranch. We keep mineral salt available at all times near their water source. Another suggestion is mineral blocks. Nutrena has mineral blocks or tubs that can help supplement anything that might be needed. We just purchased a tub for the horses at our home and are introducing it for a few hours each day.
Water: Water should be available at all times. Horses can't get the necessary amounts of water solely from eating snow, so ensure your horse has ready access to nonfrozen water at all times. Water is needed for healthy digestion. IFA and Cal Ranch have various types of water heaters available.
Teeth: Your horses teeth should be in good condition to prevent the horse from getting inadequate calories and nutrition. To keep his weight stable during the cold winter months, have teeth attended to now so the horse doesn't have to play nutritional catch-up during or immediately after the winter.
Shelter: Even a luxurious natural coat will lose insulating loft if it gets wet, and wind can strip a horse's body heat. Provide shelter at all times that allows for reprieve from the rain, snow and wind. It is recommended to let the horse grow a wooley coat prior to blanketing so they have their natural coat to provide insulation. IFA and CAL Ranch carry blankets for added protection or can be purchased through any number of websites like www.horse.com. Horse.com has a sale running this week on blankets (for horses and dogs) with FREE SHIPPING. You can find some excellent buys on this site.
Hooves: Now is the time to get your horses hooves trimmed. AAEP recommends letting your horse go barefoot for the winter season to help with traction and bruising caused by snow build-up.
Vaccinations: Check with your veterinarian about fall vaccinations, especially for the horse still exposed to others outside his regular herd. Keeping your horse properly vaccinated will help keep him healthy through the cold winter.
Parasite Control: A worming schedule is recommended to maintain a regular deworming plan. After the first heavy frost, use a product that kills bot larvae.