Skip to content
Search Library
thumbnail

Endurance horses that perform in hot environments may become dehydrated because of large sweat losses that can be as high as 8 to 9% of body weight during long-term exercise. Because large sweat losses may affect the performance or health of the horse, strategies that assist the horse in maintaining fluid and electrolyte balance during endurance exercise may be beneficial.

Absorption of water from the gastrointestinal (GI) tract into the extracellular fluid may be important in exercising horses, and it has been suggested that the composition of the diet consumed prior to competition may affect the amount of water available in the GI tract during competition.

Two studies were designed by researchers at the University of Kentucky to determine whether diet composition could affect electrolyte and water balance in horses during endurance-type exercise. Each crossover design experiment used four horses to compare the effects of consuming a high-hay/low-concentrate diet or a limited-hay/moderate-concentrate diet. Changes in body weight and plasma total protein concentrations were used to monitor dehydration.

In experiment 1, the diets were controlled only the night before the exercise test. Water intake was lower when horses received the limited-hay diet. Average weight loss during the exercise test was 2.8% of body weight and was not affected by treatment. Plasma protein concentration increased during exercise, but there were no diet-related differences.

In experiment 2, horses were adapted to the diets for 7 days prior to the exercise test and a more strenuous exercise test was used. Again, water intake was lower when the horses received the limited-hay diet. During exercise, both groups lost about 4% of body weight, but the increase in total protein concentration was lower in the horses receiving the high-hay diet. Horses receiving the high-hay diet also maintained a higher plasma potassium concentration during exercise. The increased water intake and the lower plasma protein concentration associated with the hay diet may indicate that high-hay diets are beneficial to horses involved in endurance type exercise.

X

Subscribe to Equinews and get the latest equine nutrition and health news delivered to your inbox. Sign up for free now!