Claire LELEU – Céline COTREL Pégase Mayenne – Laval - France

1. Body composition in young trotters in training :relationships to body condition score, physiological and locomotor variables during exercise Claire LELEU – Céline COTREL Pégase Mayenne – Laval - France

2. Introduction • Body composition = essential factor of physical performance • Few exceptions : swimming, weightlifting, sumos fighting… • Low fat mass : endurance, middle distance running and sprint • In horses : • 3 methods : dissection, BCS, ultrasound measurements • Ultrasound technique validated to evaluate body composition (Westervelt et al., 1976) • Significant correlation BCS and body composition (Henneke et al., 1983) • Endurance : low % F related to performance (Lawrence et al., 1992) • Standardbreds :FFM + related to performance and %F - related in elite trotters (Kearns et al., 2002) • A load of 10 % BW increases oxygen consumption by 15 % in horses on horizontal treadmill and modifies gait (Thornton et al., 1987)

3. Introduction • French races : 1609 m and 4400 m (2100 – 2800 m) • Middle distance runners • V4 and V200 : related to performance • In runners, VLt related to % F (Buresh et al., 2004) • Objective : explore relationships between body composition and BCS/physiological/gait variables

4. Materials and methods • Horses 24 two-year-old Standardbreds (16 males, 8 females) Preparation for qualification • Morphological evaluation Height at withers (HW) Total body weight (BW) Body condition score (BCS) : 0 - 5

7. Materials and methods • Body composition evaluation Ultrasound measurement of rump fat thickness  % fat  FM  FFM

8. Materials and methods • Standardised exercise test Race track, three 3-min stages at 8.33, 9.16 and 10 m/s Speed, HR, La • Physiological variables V4 / V200 3 groups of V4 • Gait variables SL/SF • Statistics : Correlations and ANOVA

9. RESULTS

10. RESULTS **p<0.05, *p<0.1 No relationship between gait variables and body composition

11. RESULTS

12. RESULTS

13. RESULTS

14. DISCUSSION • Body composition data : • % Fat :10.25 (4.7 – 14.8) • No difference in gender • % F unfit : 20 – 25 % vs % F fit : 5 – 10 % : in both Man and Horse

15. DISCUSSION • Physiological and gait data : similar to previously reported (Couroucé et al. (2002); Leleu et al. (2004)) • Correlation % F / BSC : r = 0.64 vs r = 0.65 in Henneke et al.’s study (1983) • Correlation FM/V4 : r = - 0.6 vs r = - 0.7 between FM/vLT in Buresh et al. (2004)

16. Conclusion • %F related to indirect measure of aerobic capacity • Ultrasound evaluation : non invasive, easy and reliable • Further longitudinal studies needed nutrition training