View – Final 1 2 Cobalt chloride doping in racehorses : concerns over a potentially lethal practice 3 4

16 Recent reports from Australia suggest that cobalt chloride is being used in racehorses 17 competing in New South Wales and Victoria. Although these are the first such reports, it is 18 suspected that cobalt chloride may have been used illegally for some time. Cobalt chloride is 19 a well-established hypoxia mimetic that is used experimentally to stabilise hypoxia-inducible 20 factor 1  (HIF-1) at the cellular level. It can induce hypoxia-like responses, increase blood 21 erythropoietin (EPO) levels, promote erythropoiesis and enhance the oxygen carrying 22 capacity of blood. However, prolonged administering large quantities of cobalt salts can lead 23 to serious health problems such as cardiomyopathy. Supraphysiological doses of cobalt 24 chloride may result in systemic cytotoxicity, myocardial dysfunction and acute inflammatory 25 responses in the myocardium leading to cardiac arrest and death. In this paper we review the 26 current evidence for the illicit use of cobalt chloride in racehorses. There are genuine 27 concerns that non-veterinarians are sourcing misleading information from the internet as 28 there are websites claiming that cobalt chloride can improve equine health and performance. 29 It is the duty of veterinary surgeons working in the racing industry to ensure that owners, 30 trainers and race officials are aware of the dangers of ‘amateur’ use of a potentially fatal 31 compound. 32 (202 words in abstract) 33 34