An Equine Nutrition Blog by Madeline Boast, MSc. Equine Nutrition.
The fall is a perfect time to have a nutritionist evaluate your feeding program. Ensuring your horse is on a balanced diet through the winter can make a significant difference in their well-being. It is also a great time to adjust your horse’s diet slowly prior to show season.
Entering the winter months with horses can seem daunting. Knowing how to best support your horse nutritionally is key. As the temperature drops the horse’s energy requirements change. Their energy requirements increase once the temperature is below their lower critical temperature (LCT).
What is a lower critical temperature?
The LCT is the temperature in which the horse must begin to use excess energy to stay warm. The LCT for mature healthy horses that are acclimated to their region typically have a LCT of -15°C in northern climates like Ontario. However, not all horses have the same LCT as it varies depending on acclimation time, breed, blanketing, age, health status, forage availability and shelter. For example, the LCT for young horses differs from that of mature horses. The LCT range for growing horses can range from -11 to 0°C.
So, what can we do when the temperature drops below the LCT?
For horses to be able to regulate their own body temperature, providing feed that has a high heat increment is crucial. Forage is a feed with a high heat increment because it is fermented in the hindgut. The fermentation of fiber by microbes in the hindgut produces a significant amount of heat. With this process, the horse can maintain their core body temperature.
Increasing grain intake does not contribute to warmth the same way forage does. This is because these feedstuffs are digested differently. Although grains provide extra calories, the horse will not produce warmth to the same degree as with forages. Therefore, simply increasing the energy content of their diet is not adequate. It must be done with a high heat increment feed.
The research tells us that for every degree Celsius below the LCT the mature horse needs 2.5% more energy. For young horses, the energy requirements increase by 1.3%. These percentages are based on the recommendations in the National Research Council (2007).
In conclusion, having a nutritionist test your hay to determine energy content and curate a diet based on the exact nutrient needs is the gold standard. Using energy requirements is a great tool to support your horse over the winter and reduce the chance of body condition loss.
If you have any further questions, please contact Madeline at balancedbaynutrition@gmail.com.
About the author: Madeline Boast is an equine nutritionist that founded an independent nutrition company Balanced Bay. She has worked with a variety of equids – from miniature ponies to competing thoroughbreds. Through Balanced Bay she offers hay testing, balanced diets, as well as both on-farm and remote nutrition consultations. For additional information see www.balancedbay.ca .
References:
National Research Council. 2007. Nutrient Requirements of Horses: Sixth Revised Edition. Washington, DC: The National Academies Press. https://doi.org/10.17226/11653.
Cymbaluk, N. F., & Christison, G. I. (1990). Environmental effects on thermoregulation and nutrition of horses. Veterinary Clinics of North America: Equine Practice, 6(2), 355-372.