Equine Science Update

The inadvertent carry over of medication following veterinary treatment is the most common reason for a positive drug test on the day of racing, according to the British Horseracing Authority (BHA),

An important part of the Authority's approach to keep racing drug free is the provision of data to help vets decide when drug treatment should be stopped before racing to minimise the risk of a positive drug test.

"We recognise the need to provide trainers and their vets with this important information to allow them to treat their horses but also avoid race day positive tests."

The BHA has recently announced four new Detection Times for commonly used veterinary medicines; the sedative acepromazine, the sedative /analgesic combination detomidine/butorphanol, the anti-inflammatory treatment prednisolone, and the airway treatment salmeterol.

Detection Times are the intervals between the time of the last drug administration and the time at which urine (and blood) concentrations are below the laboratory screening limit.

On its website, the BHA emphasises that a Detection Time is not the same as the Withdrawal Time used by Veterinary Surgeons. The Withdrawal Time should be longer than a Detection Time to take into account the impact of all sources of animal variability (such as age, sex, breed, training, racing) in order to avoid a positive test and to account for the effect of differences  in formulation of the medicinal product administered, route of administration, dosage regimen and duration of treatment.

The work to produce these Detection Times was performed at the BHA's Centre for Racehorse Studies, with analysis at HFL Sport Science. The Centre for Racehorse Studies is hosted by the British Racing School in Newmarket where the horses are kept at a level of training that makes them representative of horses in training.

Each medication was studied individually, with the exception of detomidine and butorphanol, which were tested in combination as they are frequently used together in practice. Each study monitored the concentrations of the medication and its metabolites in the blood and urine for eight days after administration. Six horses were involved in each study.

Changes have also been made to some existing Detection Times, with lengthening of Detection Times for the local anaesthetics mepivacaine and lidocaine and shortened Detection Times for the airway treatments ipratropium and dembrexine to reflect changes in use of those medications and progress international harmonisation.

This wider harmonisation is now proceeding rapidly; the BHA has played a leading role in intensive discussions over the last year between European racing authorities working together as the European Horseracing Scientific Liaison Committee (EHSLC) and the Asian Racing Federation (ARF). Laboratory screening limits with accompanying Detection Times for 21 common veterinary medicines have now been harmonised via the International Federation of Horseracing Authorities (IFHA).

This Detection Time advice only applies to those regulated by the British Horseracing Authority. Although similar principles apply, equestrian sport is regulated by others (www.feicleansport.org )

For more details see:

http://www.britishhorseracing.com/resources/equine-science-and-welfare/medication-control-research.asp

The current list of published Detection times is available:
http://www.ehslc.com/detection/