Old Man Winter is about to come a callin'. Are you and your horse ready for his arrival? Is your mare or gelding in adequate body condition to easily handle the cold, wet, windy weather of winter? Are you letting your horse grow a winter hair coat? Do you have ways to keep your horse's water source warm enough to prevent a reduction in water intake? Do you know at what temperatures your horse's feed needs increase? Read on to learn the answers to these questions and how to better prepare your four legged friend to handle the winter weather challenges.

An animal's "lower critical temperature" is defined as the outside temperature below which a resting animal must increase its metabolic rate to meet environmental demands for heat. That temperature varies depending on the horse's condition. A mature horse in good flesh (where ribs cannot be seen, but can be easily felt) has a critical temperature around 30ºF. Once a horse has developed a winter coat and increased its body condition to a score of 6 or slightly more, its critical temperature can drop to around 15ºF. However, young horses, old horses, thin horses, horses with health problems or those with short hair coat have a critical temperature closer to 40 or 45ºF.

Once apparent temperatures (air temperature plus wind chill) fall below the horse's lower critical temperature feed requirements increase to maintain body heat. It is estimated that for each degree Fahrenheit the apparent temperature falls below a horse's critical temperature an additional 1% DE (digestible energy) per day is needed by the horse. A rough rule of thumb is that in order to produce enough extra heat, a horse requires about 15-20% more feed for each 10ºF the apparent temperature falls below critical temperatures. These increases could be even greater in thin horse or horses with short hair coats.

The horse's winter hair coat is a very important barrier against cold. It is a surprisingly sophisticated system that traps an insulating layer of air against the skin. The hair coat functions well as long as it is "fluffed" and stays dry. Wind and rain act to flatten this system and reduce the barrier to cold. A wet horse loses body heat up to twenty times faster than a dry horse because of this flattened system. Therefore, when cold weather is accompanied by wind, rain and/or snow a horse's energy needs increase as their critical temperature is negatively impacted by the decreased effectiveness of their hair coat. One of the simplest ways to protect the functionality of the horse's winter hair coat is to provide them with adequate shelter they can use as they choose to stay out of the wind and rain.

Fat cover acts as an insulator and provides energy reserves during stress. It is recommended that horses enter the cold weather season in a body condition of approximately 6 which is slightly on

the fat side. The extra body fat will protect the horse against the cold, lower its critical temperature and give it some reserves to draw on for energy and body heat. It may be difficult for horses to increase body condition during extremely cold weather; therefore, horses should be proper body condition prior to the arrival of the cold weather.

During long bouts of freezing temperatures, most horses will experience some loss of body condition, no matter how well they are fed. That is why it is important to monitor your horse's body condition regularly throughout the winter. A long winter hair coat makes it more difficult to assess body condition visually. Therefore, routine body condition checks should be done by using your hands to feel fat and muscle cover on your horse's ribs and bones of the pelvis and spine through his winter hair coat.

It is a common misconception that grain is the heat producing feedstuff of choice for horses during cold weather. However, roughage (e.g. hay) actually produces more internal heat than grain when digested because heat is a resulting by-product of the fermentation process hay goes through in the hindgut. Grain provides a lot of energy, but little heat as it is easily digested in the horse's foregut without the heat producing fermentation process. This means that good quality hay is the preferred feed when it comes to internal heat production and making your horse warmer from the inside out. Grain comes into the winter feeding equation if your horse is thin and needs the high calories grains provide to put on weigh.

Water's importance does not diminish in cold weather as some may think. In fact, water needs for horses often increase in the winter when they are on a dried forage diet instead of on fresh green pasture. Increased hay intake combined with decreased water consumption can potentially lead to impaction colic. It is important to note that snow does not provide adequate water to meet a horse's needs. Six times as much snow must be eaten to provide an equal amount of water. Furthermore, calories are used to melt the snow that should be used for body warmth.

Water should be ideally at about 45º as horses will drink less water if it is too cold. Stock tank heaters, bucket heaters, heated buckets or heated automatic waterers should be utilized to keep water at sufficiently warm temperatures to encourage horses to drink adequately. Otherwise, icy water in buckets should be replaced by tepid water a minimum of twice a day and unheated water sources should have the surface ice broken at least twice a day. Horses often drink right after a hay meal, so their warm water source should be available to them then.

Utilizing the information above as you care for your horse through the harsh winter season will help keep your horse warm and cozy, and happy and healthy all winter long.

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