Physiological comparison of conditioned and non-conditioned university horses following semester break.

Periods of limited activity during semester break may reduce performance during return to ridden work. This study evaluated fitness and muscling of horses when returning to work, following a 12-week period during which horses either continued (conditioned) or discontinued (non-conditioned) ridden work. It was hypothesized that non-conditioned horses would have a lower level of fitness, resulting in higher resting and peak heart rates and lower levels of muscling. Twelve mature, stock type horses aged 16 ± 5 years were assigned to either a conditioned group that maintained light-to-moderate riding or a non-conditioned group receiving no formal exercise. All horses had access to voluntary exercise for 12-24hr/d on grass pasture (1.5-2.5 hectares). Following the 12-week period, all horses were placed into a light-to-moderate intensity exercise program with resting heart rate, peak heart rate, body condition score, gaskin and forearm circumference, and topline muscle measurements performed on d 0, 14, and 28. Peak and resting heart rates were not different between groups (P > 0.05) but increased for both groups throughout the study (P = 0.04). Gaskin circumference of non-conditioned horses was larger (P = 0.04), although non-conditioned horses tended to be heavier (551.4 versus 491.4 ± 21.4 kg; P = 0.07). Conditioned horses had greater average topline muscling scores (P = 0.02). Horses that were conditioned over a 12-week break had greater muscling, but changes in fitness were not detected. Pasture access could contribute to maintenance of fitness during unridden periods.