Cobalt chloride given intravenously to horses can cause anxiousness and, at higher doses, spark muscular tremors, pawing and signs of abdominal discomfort, according to researchers.
Scientists conducting a pilot study into cobalt use in horses, funded by the Ohio State Racing Commission, have found the substance can consistently triggered cardiac arrhythmias, a fast heart beat, high blood pressure and kidney problems.
Cobalt, a naturally occurring element, has been at the center of international efforts in racing to eliminate its illicit use.
It is found naturally in horses at low levels, but at higher levels is considered by some to be performance-enhancing by boosting the oxygen-carrying capacity of the blood.
Researchers at Ohio State University’s College of Veterinary Medicine have completed the first phase of their assessment of the physiologic, biochemical and endocrine effects of repeated doses of intravenous cobalt chloride in five Standardbred mares.
For the work, each horse received one of five different doses of cobalt chloride (0.25, 0.5, 1, 2 and 4 mg/kg) weekly for five weeks.
A research summary, entitled Intravenous administration of cobalt chloride is associated with hemodynamic alterations in horses, by Teresa Burns, Turi Aarnes, Jeffrey Lakritz, Ramiro Toribio, was presented at the 2016 American College of Internal Veterinary Medicine meeting in June.
The study team noted a transient increase in hematocrit and red blood cell counts in the horses. However, changes in erythropoietin concentrations or changes in erythropoiesis or red blood cell numbers were not seen during the study period.
Baseline plasma cobalt levels in the subject horses were 3.6 ± 3.1 ppb (parts per billion). The plasma half-life of cobalt for all horses in the study was 12 ± 1.4 days and the time required for cobalt to be below 25 ppb ranged from 40 days (0.25 mg/kg dose) to 90 days (4 mg/kg dose).
Laboratory and data analyses are ongoing, specifically: measurement of urine cobalt concentrations to further investigate pharmacokinetics of cobalt and measurement of endocrine variables and markers that may be linked to performance.
Regardless of what further research may show on cobalt use, the initial findings prove that cobalt chloride given intravenously can harm horses.