The Equine Science Society is a group of equine scientists specializing in nutrition, exercise physiology, reproductive physiology, genetics, bioscience, production and management and teaching and extension. Their conference was held at the end of May, and over the next few weeks I will post about some interesting research that was presented. The abstracts and invited papers are all published in the May edition of the Journal of Equine Veterinary Science (volume 52).
An interesting study for the Thoroughbred industry was regarding Furosemide (Lasix) usage long-term.
Lasix is commonly used to decrease the incidence of exercise induced pulmonary hemorrhage (EIPH), by acting as a diuretic and subsequently decreasing blood volume and pressure (the most accepted theory on why EIPH happens is due to increased blood pressure in the pulmonary capillaries, leading to their rupture and blood leaking into the alveoli).
Many trainers administer Lasix at each race, potentially over several months or years of a horse’s racing career.
The study by A Pritchard (Abstract 67) looked at the long-term effects of Furosemide on body weight loss after administration (which is a measure of how effective it is because the diuretic effect causes the horse to urinate and decrease blood volume and thus body weight).
After seven weeks of once-weekly administration of Furosemide (at 1mg/kg BW dosage, administered IV), the amount of body weight lost following its administration decreased over time. This suggests that horses may develop drug resistance and Lasix might be less of an effective preventative tool for EIPH.