Muscle characteristics and plasma lactate and ammonia response after racing in Standardbred trotters: relation to performance.

This study explores the correlation between muscle characteristics, plasma lactate and ammonia concentrations after racing with the performance index (IPI) of Standardbred trotter horses. The findings suggest that there is no significant relationship between these factors and the IPI.

Research Methodology

• The researchers carried out biopsies and blood samples from the jugular veins of 25 Standardbred trotter horses, 5-10 minutes post racing. They analyzed the biopsies for fibre type composition and enzymatic profile.
• The blood samples were analyzed for plasma lactate and ammonia concentrations.
• The scientists compared these muscle characteristics and plasma concentrations with each horse’s individual performance index (IPI).
• The IPI of each horse was calculated annually from the individual horse’s racing performance – this included their racing placement, total annual earnings, average earning per start, and best racing record.
• In addition to the above, ten horses were also given a submaximal test on the racetrack, consisting of 5 incremental 1000 m heats at approximate speeds. After each heat, a blood sample was taken for plasma lactate analysis.

Key Findings

• The study showed a wide range of plasma lactate concentrations (15.0-42.7 mmol/l) and ammonia concentrations (65-210 micromol/l) in participating horses after racing.
• There was also varied fibre type composition among horses. However, the composition seemed to be predominantly type IIA fibres.
• Despite these observations, the data gathered showed no correlation between fibre type composition, enzyme activities, plasma lactate and ammonia responses to racing with IPI.
• The results from the submaximal track test were also in alignment with this, as there was no observed correlation between plasma lactate response to exercise and IPI.

Conclusions and Implications

• The study concluded that muscle characteristics, plasma lactate and ammonia concentrations after racing do not correlate with the current race performance (expressed as IPI) in a group of horses. This was consistent even amongst horses with average or better performance capacity.
• Therefore, the analysis of lactate and ammonia in blood after racing is not a valuable tool to predict an individual performance index for horses.
• This could be significant in horse training and healthcare, as it challenges previous assumptions about the use of lactate and ammonia concentrations as reliable indicators of performance. This could potentially inform the development of more effective performance prediction methods.