Prerace venous blood acid-base values in standardbred horses.

The research explores the use of sodium bicarbonate, also known as ‘milk shakes’, in Standardbred horses before racing. The study analyses the changes in venous acid-base values from these horses, concluding that the use of such substances resulted in changes in these values. The research also suggests the use of a single index, base excess value, as a criterion for disqualification to curb the administration of sodium bicarbonate to horses.

Research Context and Methodology

• The study revolves around the practice of administering sodium bicarbonate or ‘milk shakes’ to Standardbred horses before racing, common in Pennsylvania (PA) and New Jersey (NJ). This procedure is believed to impact the horse’s performance.
• The acid-base values in the horse’s blood were monitored both on nonrace days (CTL) and prerace days. The horses were stabled at Pocono Downs, Pennsylvania, during the 1993 racing season.
• The study also considered horses administered frusemide (F) 4 hours before the race and horses not administered frusemide (NF), exploring variations in both groups’ acid-base values.

Research Findings

• The results showed differences in acid-base values between CTL and prerace samples, especially in pHv, PvCO2, HCO3-, and BE. The acid-base values for CTL horses were found to be normally distributed, while prerace values were not. This abnormal distribution indicates potential changes caused due to the administration of alkalising substances or other race day manipulations.
• Changes were noticed in all acid-base values in the following 1994 racing season and when horses were secured in a stable 8 hours before the race.
• The study pointed out that some racing jurisdictions disqualified horses based on certain elevations in HCO3-, Na+, and pH. However, the correlation between these 3 acid-base values was found to be weak.

Research Implications and Recommendations

• To discourage the administration of sodium bicarbonate before a race, the research suggested using a base excess (BE) value as an index. A BE value of >= 10 mmol/l for NF and >= 12 mmol/l for F was proposed as a cut-off for disqualifying horses.
• According to the study’s outcomes, the introduction of this single index, specifically the BE, effectively curbed the prerace administration of sodium bicarbonate to horses. This method could provide a simple and effective way to ensure fair competitive conditions in horse racing.