Energy balance of sport horses working in riding school at two levels of intensity

This trial aims at the validation in field conditions of energy requirements proposed by INRA-1990 for exercising sport horses. Eighteen horses were split up in two groups bases on their working intensity: exercised by beginners (group A) or sport (group B) riders. The horses were fed wheat straw, hay and compound feeds, 50-0-50 percent or 27-11-62 percent for groups A and B, respectively. The net energy (NE) content of the two diets, determined by indirect calorimetry according to INRA method, was 0.62 and 0.72 UFC/kg DM for groups A and B, respectively. Horses in groups A and B worked daily 120min and 50min, respectively. The duration of exercise was measured daily and the intensity of exercise was checked once a week by measuring the velocity of the gaits implemented during the work. The body weight (BW) variation, estimated by regression of BW and measured weekly, is slightly positive (+200g/d) for group A and constant for group B. The Body condition score (BCS) variation measured biweekly using INRA 1990 method, (scale 0 to 5) was slightly positive (+0.18 point BCS) for group A and constant for group B. Energy balance was slightly positive for group A (+4percent) and balanced for group B. Nutrional balance is discussed in respect of INRA requirements.