Estimation of performance potential of Standardbred trotters from blood lactate concentrations measured in field conditions

The purpose of this study was to examine the relationship between V-4 (velocity which results in a blood lactate concentration of 4 mmol/l), age and racing performance of Standardbred trotters and to establish V-4 normal values to select good and poor performers, The specific influence of racing (RT) and training (T1 and T2) tracks was also examined, A total of 159 horses were divided into 5 age-groups from 2 to 6 and over and performed 330 standardised exercise tests of 3 steps performed at increasing speeds, The velocity of the horses was measured with a tachometer on the sulky Blood lactate concentrations were measured from the jugular vein after each step. For the 5 age-groups, mean V-4 values increased significantly (P<0.05) with age between 2 and 4 years. After 5 years, this increase was reduced and became nonsignificant. The highest V-4 values were obtained on the racing track (RT) and the lowest on the training tracks (T1; P<0.05). No significant difference was found between RT and T2 nor between T1 and T2. Horses were defined as good performers (GP) when finishing between the first and the fifth place in a race or poor performers (PP) when finishing lower than fifth, V-4 was significantly higher for GP than for PP (P<0.05). Normal value of V-4 were established for goad and poor performers taking into account the 95% confidence interval of the data, Therefore, V-4 depends on age and track and can be considered an important parameter to evaluate trotters' racing potential.