The California Horse Racing Board has begun monitoring cobalt levels in horses that are competing in the state and in certain necropsy specimens.
In an advisory to horsemen issued March 4, CHRB equine medical director Dr. Rick Arthur said that cobalt toxicity has been associated with myocardial and other organ pathology in humans and other animals. High cobalt levels have been associated with the parenteral or oral administration of cobalt salts.
While there is no documented evidence of cobalt toxicity in race horses, the CHRB considers the administration of cobalt salts a potential equine health and safety issue, Arthur said.
Cobalt in excess of 5 parts per billion in blood (serum) or 25 ppb in urine, will trigger an investigation to determine the source of the cobalt, according to the advisory. Until specific criteria are determined, the top 10% cobalt levels from necropsy tissue specimens will trigger an investigation to determine the source of the cobalt.
Water soluble cobalt salts have a number of industrial and agricultural uses, such as an ingredient in the manufacture of feed and mineral supplements. They are not intended for administration to horses.
Arthur noted that CHRB rule 1902.5 prohibits the administration of any noxious or harmful substance to a horse.
Cobalt is an essential element present in Vitamin B-12, Arthur noted in the advisory. There is no evidence that Vitamin B-12 injections will produce abnormally high cobalt readings. Nor will normal equine vitamin and mineral supplements. Low concentrations of cobalt salts found in routine feed and vitamin/mineral supplements are legal and not found to be harmful.
Arthur requested that any incidents of improper cobalt administration be reported to CHRB investigators.