Harness racing trainers are reminded that the presence of arsenic above a level of 0.30 micrograms per millilitre in a raceday equine urine sample is a prohibited substance.
Trainers are further reminded under Australian Harness Racing Rule(AHRR) 190 (4) that an offence is committed if a horse is presented with a prohibited substance in its system, regardless of the circumstances in which the prohibited substance came to be present in the horse.
Products that contain arsenic include but are not limited to Ferrocyl, Jurocyl, and Invigorate injections. It is claimed the use of these injectable preparations on horses may improve appetite and the appearance of the hair coat, and may aid in the treatment of anaemia or general weakness. However, there is no rational evidence-based indication for the use of arsenic in horses. Arsenic containing substances are not routinely used nor recommended as treatment for any medical condition in horses.
Arsenic is an element that naturally occurs in the environment in very small amounts in rocks, soil, water, air (from volcanic eruptions) and plants. Therefore horses, like all species may normally inhale or ingest very small amounts of arsenic. As a result, trace amounts are normally found in animal tissue and are excreted in urine. Mining activities that expose rocks and soil to weathering can result in increased levels in local soil and water. However, environmental contamination in Australia is likely to be extremely low and not exceed a few parts per million (ppm) unless a horse lives in a contaminated mining area.
Arsenic is used in the production of pesticides and herbicides, although these applications are declining. Use of arsenic containing insecticides for management of cattle tick and lice problems in sheep was banned in 1987 yet soil around the site where the ‘dip’ once was on farms may remain contaminated with arsenic for many years. Arsenic is still used as chromated copper arsenate (CCA) and arsenic trioxide for its insecticidal properties to treat timber (ie. to prevent termite damage). This can give treated timber such as pine posts a greenish tint.
During investigations into current arsenic irregularities reported by Racing Analytical Services Limited (RASL), HRV in company with other racing authorities and RASL engaged the University of Melbourne to conduct a trial to research the levels of arsenic in horses that had ingested a known amount of CCA treated timber sawdust. This administration resulted in urinary concentrations of arsenic that exceeded the threshold concentration in some of the horses.
Therefore, it may be possible that a horse could have a urinary level of arsenic that exceeds the threshold concentration if it chews and ingests a sufficiently large quantity of CCA treated timber. With this aspect of the research completed, trainers are placed on notice that an explanation of environmental contamination (through CCA timber or other means) will not necessarily be considered a significant penalty mitigating factor for anyone found to have presented a horse with urinary concentrations above the arsenic threshold in the future. Trainers are advised to take measures to ensure that racing horses do not have access to environmental sources of arsenic including treated timber products.
Further research will be conducted in the future in an effort to determine whether the source of arsenic detected within a particular equine urine sample is due to the ingestion of the inorganic form of arsenic in CCA treated timber or the organic form of arsenic (sodium arsanilate) in intravenous preparations of arsenic tonics available for use in horses.
Queries can be directed to your veterinarian or the HRV Integrity Department on (03) 8378 0222.