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Veterinary Health Center

Equine - Timely Topics

Horse Health And Winter Weather

Beth Davis, DVM, PhD, DACVIM-LAIM, Professor and Head, Equine Internal Medicine and Surgery

2 horses in fieldAlthough it is a busy time of year with the holidays here and many responsibilities for everyone, we need to be sure that we don’t forget about our equine friends that are out in the stables and pastures. In preparation for winter weather it is ideal to have a check list prepared to ensure that we have covered all bases to help minimize the chance that we will be dealing with weather-related illness in our equine herd. Areas of particular concern include available water, appropriate nutrition and prophylaxis (prevention) from infectious respiratory disease.

Impaction Colic

Colic is word that no horse owner wants to hear, but it is a general term used to describe horses that exhibit abdominal pain. One form of colic that we may encounter during the winter months is impaction colic, specifically an impaction of the large intestine (colon). Horses may develop impactions for a variety of reasons, but if they have reduced access to water due to freezing, this can put them at an increased risk for impaction colic. It is important that horse owners have a water plan when the temperatures drop below the freezing mark. This may be accomplished in a few ways. Having a stock tank deicer in the water tank will keep water from freezing; generally the water is maintained at approximately 40°F. If this is not possible, then a stock tank should be monitored and when it is frozen it should be cracked and the large pieces of ice at the top removed. This will allow the horse an open space to drink from, but only for a short period of time. Of course the time available to drink from the opening will depend on the ambient temperature. Colder temperatures will result in freezing more quickly. Horses should have access to water a minimum of twice daily. This cracking ice protocol can be applied to other forms of iced over water such as with a pond or other standing water.

Food for Warmth

Since horses are hind gut fermenters eating forage will help them stay warm when the temperatures are low. Horses should have free choice access to good quality grass hay so they can continue to eat forage, but not ingest excessive calories. Horses should eat a minimum of approximately 2% of their body weight each day in forage, for the average sized Quarter Horse this is approximately 20 pounds daily. Hay should be weighed to ensure appropriate amounts are fed, but as a guide most square bale hay is roughly 5 pounds per flake, which means that horses should ingest a minimum of 4 flakes of hay in 24 hours. In addition to good quality forage some horses may require supplementation with concentrate (grain) during the winter months in order to maintain an ideal body condition. Concentrate is typically fed at a rate of 0.5% body weight daily, which works out to approximately 4-6 pounds of concentrate daily for the average Quarter Horse, divided into 2 feedings to avoid overfeeding (approximately 2 pounds twice daily for a total of 4 pounds in 24 hours). The type and amount of grain to provide to your horse will depend on several factors, but a few to keep in mind include age of your horse, current body condition, exercise level, type of forage that is available and frequency of feeding. It is advisable to work with your veterinarian or an equine nutritionist that is familiar with your horse and the type of diet your horse is receiving to make specific dietary recommendations.


Similar to humans, when the temperature drops outdoors, prophylaxis from infectious respiratory disease should be implemented. Cold weather is stressful for animals that live outdoors; stress has a direct physiologic effect that results in immune suppression. Proper vaccine administration can help to enhance immune protection during times of stress and potential exposure to microorganisms that may result in infection. A complete listing of equine vaccine protocols can be reviewed on the AAEP website. In general, core vaccines should be administered in the spring months to help protect against encephalitic diseases (EEE, WEE, WNV), tetanus and rabies. In addition, protection from infectious respiratory disease (risk-based) can be achieved with good vaccine practices that include vaccines for equine influenza (EIV) and equine herpesvirus 1 and 4 (EHV-1/4) in the spring with booster vaccination administered in the fall. The fall booster will enhance immune responses when immunity may be reduced due to outdoor weather conditions.

It should be mentioned that other factors may reduce immune function in horses that include being in cold weather without protection from wind and precipitation. A grove of trees, 3-sided shelter or winter turnout blanket can help protect horses from the elements. If a stable is available, when wind is strong or there is moisture precipitation (rain, sleet, snow), moving to an indoor stall will provide ideal protection from the outdoor elements.

Collectively, maintaining healthy horses in the winter months can be successfully achieved when horse owners are aware of potential problems that may be weather-related. A quick check list can help avoid weather-related conditions during winter months.


  • Water availability

    • Stock tank deicer

    • Crack ice and remove large pieces from top of trough, twice daily

  • Nutrition

    • Good quality forage, brome or prairie hay (2% of body weight daily)

    • Concentrate grain for horses that lose condition in the cold weather (0.5% body weight daily)

  • Prophylaxis from infectious disease

    • Go to the AAEP website to review all vaccine protocols

    • Booster vaccinate for EIV and EHV-1/4 in the fall

    • Protect from elements with blanket, shelter and/or stabling.