As fall gives way to winter, attention for many horse owners turns to nutritional management considerations for their horses. For owners living in the southern United States, there are some minor alterations. Whereas, for those owners in the northern United States or in Canada, there are major considerations and alterations.

The first consideration for any horse owner is to consider how the winter weather in their area of the world might influence their horse’s dietary requirements. Briefly, as ambient temperatures drop with increased cold rain and even introduction of snow, all will increase an individual horse’s daily requirement of dietary nutrients. The most important of which is energy (calories).

With increased nutritional demands, owners will need to feed more each day to keep pace. Therefore, it is natural to start with winter forage availability when adjusting any feeding plan. Here is a brief review of which cool-season forages are generally accessible to horses in North America.

  • Kentucky Bluegrass
    • Cool season grass
    • High nutritional value with range CP (crude protein) 12-17% and DE (digestible energy) 0.86 to 1.04 Mcal/lb
    • Dormant during warm summer months
  • Ryegrass
    • Cool season grass
    • Moderate to high nutritional value with range CP 11-17% and DE 0.82 to 1.0 Mcal/lb
    • Susceptible to temperatures below 41°F and above 87°F
  • Timothy
    • Cool season grass
    • Moderate nutritional value with range CP 11-15% and DE from 0.82 to 1.04 Mcal/lb
    • Lower quality as plant matures
  • Alfalfa
    • Cool season legume
    • High nutritional value with range CP 18-22% and DE from 1.0 to 1.2 Mcal/lb
    • Requires well drained and fertile soils
  • Clover (Red)
    • Cool season legume
    • High nutritional value with range CP 15-22% and DE from 1.0 to 1.3 Mcal/lb
    • Shorter growing season

The drastic differences in winter weather patterns between areas will also have major implications as to which of these winter forages will be available. In the southern United States, where it is typical to have a mild winter, cool season forages usually have a longer growing season and survive longer. For example, the optimal ambient temperatures for growth of most cool-season forages is 55 to 80 °F. When temperatures drop consistently below 55°F, the cool season forages will die off. However, most cool season forages can survive short periods of sub-optimal (< 55 °F) and even freezing temperatures. An exception would be ryegrass, which can survive temperatures as low as 41 °F, but follows a similar pattern when temperatures drop below that threshold.

For pastures that are not planted with any cool season forages, it is recommended that horses are kept off and fed hay in a sacrificial area during the winter. This will help prevent permanent damage to your pasture. Likewise, if your pastures are planted with cool season forages and growth has stopped, horses should be moved to a sacrificial area until the pasture becomes productive again.

Daily requirements during the winter of course will always depend on the class of the horse and its use. However, it is generally recommended that horses are provided more hay during the winter months. The breakdown of the fiber in hay by the microbes in the hindgut of the horse produces heat. More hay leads to more fiber in the diet and thus, more body heat is produced.

Just how much more hay to feed in the winter months will, of course, vary on the intensity of the winter weather in your area of the world. In extremes, hay requirements may increase up to 50%.  A good rule of thumb proposed by experts from North Dakota State University suggests feeding an extra 2 pounds of hay for every 10° the temperature drops below freezing (32 °F) for the averaged sized horse. It is also suggested to feed your horse more often during the winter, such as 3x per day, rather than 2x per day. The reasoning for this is because fiber will be available to the hind gut for an extended duration. Thus, the microbes would help produce heat over a longer period of time.  

It is worth noting that an increase in hay alone will not always help a horse maintain condition through the winter months. A higher calorie feed, or even fat supplement, can help horses thrive. For example, K Finish® is a high fat (25%) supplement that can be added to a feed to help horses meet their increased caloric requirements and maintain body condition during the winter.

If you have any questions about your winter-feeding plan or concerns about your winter forages, please feel free to reach out to our team of experts for advice.

Chris J. Mortensen, Ph.D.