The Indiana Horse Racing Commission (IHRC) said on Jan. 12 that their regulation of cobalt, a naturally occurring substance in racehorses that can have performance-enhancing qualities when supplemented, indicates decreases in its abuse.

The IHRC cited a staff report based on testing results. A cobalt regulation was adopted Sept. 4, 2014, for Thoroughbred, Quarter Horse, and Standardbred racing in the state after 354 samples drawn during the summer of 2014 were tested at the Kentucky Veterinary Diagnostic Laboratory.

During what the IHRC called a "pre-regulation period," 5.9% of tested samples indicated cobalt concentrations in excess of 25 parts per billion, the threshold level adopted by the regulatory agency. The staff report states there was an 83% decline in cobalt concentration over the regulatory threshold since the effective date of the regulation.

Test results during the regulated period indicate that across all breeds, the median cobalt concentration was 3.0 parts per billion, and that 93% of all horses tested for less than 10 parts per billion. Samples tested last summer produced 11 results at more than 100 parts per billion, the IHRC said