Increased Metabolic Rate: How Horses Burn More Energy to Stay Warm

One Minute Read: Increased Metabolic Rate: How Horses Burn More Energy to Stay Warm

Understanding Cold-Induced Thermogenesis

When temperatures fall below a horse's lower critical temperature (LCT) — the point at which they must increase metabolic activity to maintain core body temperature — their body begins to burn more calories to stay warm. This cold-induced thermogenesis is a fundamental physiological adaptation that enables horses to survive in subfreezing temperatures.

The Thermoneutral Zone and Energy Demands

A horse's thermoneutral zone (TNZ), where no extra energy is required for heating or cooling, generally ranges from 5°C to 25°C (41°F to 77°F) for a mature, healthy horse with a full winter coat. Below this range, horses begin to increase their metabolic rate, burning energy to generate heat through processes such as muscle activity (including shivering), cellular metabolism, and improved digestion. A classic study found that horses may need up to 15% more dietary energy for every 10°C drop below their LCT.

Adjusting Feed Intake for Winter Months

Without a corresponding increase in calorie intake, horses may lose weight in winter, even if their workload hasn't changed. Thus, adjustments in feeding during cold weather are crucial, ideally increasing forage intake rather than concentrates. Forage supports not only energy needs but also fermentation heat production, which adds another thermal benefit.

Monitoring Vulnerable Horses

Older horses and those with poor dentition or health issues may not increase feed intake voluntarily, so close monitoring of body condition is essential. Preventing weight loss before it begins is far easier than reversing it midwinter.

References:

– Morgan, K. (1998). Thermoneutral zone and critical temperatures of horses. Journal of Thermal Biology, 23(2), 59–61.

– University of Minnesota Extension. (2021). Caring for Your Horse in Winter. Retrieved from

– Rutgers Equine Science Center. (n.d.). Nelson Investigates Horses in the Winter. Retrieved from