Urinary excretion of dietary contaminants in horses.

This research article investigates the presence of dietary contaminants in horse urine, potentially leading to false positive results in anti-doping tests. The findings highlight the importance of carefully selecting feed materials for horses to avoid inadvertent ingestion of substances prohibited in equine sports.

Objective and methodology of the study

• The primary goal of this study was to examine the amount of various contaminants a horse can consume through their diet that would result in detectable concentrations in their urine. Because many equine sports ban any presence of drugs in post-race urine samples, understanding these thresholds is crucial to avoid unintentional doping.
• Substances such as caffeine, theobromine, theophylline, atropine, scopolamine, bufotenine, DMT, and morphine were administered orally to six horses under varying dosages for three days.
• Subsequently, the horses’ urine was sampled and tested for traces of these drugs to understand the link between dietary intake and urine concentration.

Key findings

• The results showed that daily intake of theobromine, theophylline, bufotenine, and morphine greater than 10 mg, 2 mg, 10 mg, and 200 microg respectively, resulted in detectable amounts in the horses’ urine.
• Atropine and dimethyltryptamine, even when administered in dosages of 5 and 15 mg, and 3 and 10 mg respectively, were not found in the urine.
• Both caffeine and scopolamine, at the lowest tested dosages (5 mg/horse/day and 2 mg/horse/day respectively), led to detectable concentrations in the horses’ urine.

Conclusions drawn

• The study concludes that even dietary contaminants consumed below their effective dosage can lead to a positive result in anti-doping urine tests.
• The results suggest further research is required to confidently establish safe daily intake amounts for substances like caffeine and scopolamine.
• The selection of feed materials is of great importance in preventing unintentional positive results in anti-doping tests, as some substances do appear in urine even when consumed at relatively low levels.