Effects of flunixin on movement and performance of standardbred trotters on the track.

This study investigates the impact of the nonsteroidal anti-inflammatory drug flunixin on the movement and performance of Standardbred trotters, finding that while it does not affect maximal speed or metabolic response, it alters the horse’s locomotor pattern.

Methodology

• The researchers used five adult Standardbred horses in training for this study. These horses were made to trot on two separate occasions, two weeks apart, on the same oval dirt track.
• Four hours before each performance test, the horses were injected with either flunixin meglumine (Finadyne) or a normal saline solution. This was done in a double-blind crossover study format, meaning neither the researchers nor the horses’ handlers knew which substance was being administered.
• The kinematics – the study of motion – for five consecutive strides were filmed to record any movement pattern changes.

Key Findings

• Flunixin had no significant impact on the maximum speed of the trotters. Equally, no notable differences were observed in heart rate and plasma lactate levels after flunixin treatment, indicating that the drug did not affect the metabolic response of the horses.
• Notwithstanding, flunixin had a significant impact on the horses’ locomotor pattern. Even though stride duration was maintained, stance time was significantly reduced and swing time in the forelimbs was increased. Additionally, the range of limb angles underwent a significant decrease.

Conclusions and Implications

• The results imply that flunixin, while not altering the horse’s speed or metabolic response, does significantly affect its movement pattern.
• The overall impact on racehorse performance could thus be linked to NSAIDs‘ anti-inflammatory and analgesic properties, which potentially mask pain and lameness.
• This could have implications for the use of NSAIDs in horse racing, as their ability to mask pain could lead to damaging consequences for the horse’s physical welfare if not carefully managed.