Antioxidant Status in Three-Day Eventing Horses Studied

Researchers found that antioxidant levels in upper level three-day eventing horses appear to be challenged during the competition, but effects can vary depending upon the horse's diet, level of competition, and level of fitness.

Photo: Erica Larson, News Editor

Rigorous competition, such as three-day eventing, affects the equine athlete physiologically in many ways, but how does it affect an animal’s antioxidant status?

Recently, researchers from Rutgers University and the University of Maryland set out to answer this question, and their study results showed that antioxidant levels appear to be challenged during the competition, but effects can vary depending upon the horse's diet, as well as its competition and fitness level. 
Oxidation is the natural process that occurs when oxygen is combined with various other elements in the body during metabolism.  "In animals and humans, the rate of oxidation depends on the amount of activity that's occurring," reported study leader Carey Williams, PhD, equine extension specialist and associate director of the Rutgers University Equine Science Center. 
"Antioxidants … have protective action against excessive [oxidative] damage," she added. 
The research team evaluated 42 horses during an international two-star (CCl2*) and three-star (CCl3*) three-day event. Upon voluntary enrollment in the study, blood was collected from horses and analyzed for specific antioxidant levels before competition (PRE), directly after the cross-country jumping phase (XC), and 18 to 24 hours after cross-country jumping phase (POST). Researchers also surveyed owners regarding the nutritional management of participating horses. 
Data revealed CCl2* horses had more pasture turnout, "the number one source for antioxidant vitamins," according to Williams, and additional antioxidant supplements than did CCl3* horses. Not surprisingly, blood results showed these horses had higher PRE and XC levels of the beta-carotene, an antioxidant abundant in pasture, than CCl3* horses.
At XC, the CCl3* horses had higher levels of creatine kinase and aspartate aminotransferase, markers of potential muscle membrane breakdown, as well as lower levels of some additional antioxidants than did CCl2* horses. This indicates, "more of a challenge being placed on the CCl3* horses," said Williams in the study. 
To ensure any horse is receiving enough antioxidants, Williams recommends, "at least a few hours a day of pasture turnout." For horses without pasture access or those competing heavily, she recommended "either a multi-antioxidant supplement at the recommended levels on the label or at least 2,500 IU of vitamin E per day."
The study, "Antioxidant Status in Elite Three-Day Event Horses during Competition" appeared in Oxidative Medicine and Cellular Longevity in June 2012 and can be viewed in its entirety online

About the Author

Casie Bazay, NBCAAM

Casie Bazay holds a bachelor of science degree in education from Oklahoma State University. She taught middle school for ten years, but now is a nationally certified equine acupressure practitioner and freelance writer. She has owned Quarter Horses nearly her entire life and has participated in a variety of horse events including Western and English pleasure, trail riding, and speed events. She was a competitive barrel racer for many years and hopes to pursue the sport again soon.

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