Researcher say Cobalt Misuse in Horses is 'Ill-Conceived'

POSTED ON  |  21-11-2019

Since Georg Brandt discovered cobalt in 1793, people have exploited its virtues for a wide range of uses, from paint pigmentation with its rich blue color to enhancing human athletic performance. Because some racehorse trainers in the United States and Australia have abused cobalt in horses, an Australian research team recently investigated cobalt concentrations in urine and blood after chronic cobalt administration to determine whether current regulatory drug detection thresholds proved useful for this purpose.

“Cobalt is an essential trace element required to synthesize vitamin B12, which plays a vital role in cellular metabolism and DNA synthesis,” said Ross Wenzel, GradDip (ClinBiochem), MAppSc (Thesis) of the Trace Elements Laboratory at the Royal North Shore Hospital, in New South Wales.

An average 500-kg (roughly 1,100-lb) working horse, fed approximately 2% of its body weight in forage per day, requires 0.1-0.15 mg cobalt/kg/dry feed daily. These levels typically can be met through diet alone and, because no known reports of cobalt deficiency exist, equine nutritionists advise a maximum of 25 mg/kg dry matter intake. “The rationale for supplementing horses with cobalt pertains to a presumptive increase in red blood cell production in response to cobalt indirectly inducing hypoxia,” Wenzel said. In turn, more oxygen will be delivered to exercising muscles to maximize energy production and enhance performance.”

In other words, some people believe that giving cobalt indirectly diminishes the amount of oxygen reaching the muscles, causing the body to compensate, producing more red blood cells to deliver more oxygen to the muscles. “Research has failed to support this presumption,” he added. “There is no evidence to suggest that cobalt will stimulate a hypoxic response in excess of that naturally achieved in training.” “With the range of unnecessary cobalt-containing supplements on the market, the need to develop a testing regime capable of differentiating cobalt misuse from regular supplementary intake is apparent,” said Wenzel.

He explained that his group pursued the study “on the initiative of study co-author and equine veterinarian Derek Major in response to a high rate of racing cobalt infringements where anecdotally, up to 500 mg of cobalt chloride were being administered intravenously. To better understand how horses metabolize cobalt, Wenzel and coworkers administered 25-50 mg cobalt chloride intravenously once to twice weekly for 10 weeks. They assessed both urine and blood cobalt concentrations routinely during the study period and again 81, 106, and 127 days after its commencement.

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