It may sound barking mad, but the last two years have seen hair testing professionals called in to do a drug test with hair for racing greyhounds to search for the class A drug, cocaine. Trainers dope their dogs for a racing advantage - cocaine makes dogs hyperactive, running faster - and to fix race results. Dogs are sedated in races to lengthen their odds for later events, and then raced without sedatives or with stimulants to improve their performance on a given day.
The Greyhound Board of Great Britain (GBGB) - the governing body for dog racing in the UK - has increased drug testing over the last decade, and reports that 99% of tests come up negative. However, 261 positive tests for banned substances over four years indicates an ongoing cause for concern.
A GBGB disciplinary hearing early in 2019 was decided by hair test results: the test showed cocaine incorporated in the dog’s hair, to a level indicating several days’ exposure or a shorter, larger dose that took longer to wear off. Earlier cases, in which urine tests were used, required three tests over a period of two months to confirm the presence of cocaine metabolites..
With trainers’ reputations and fines of between £500-£1500 on the line - not to mention the animals’ health and wellbeing - an accurate and well interpreted test result can be crucial.
Canine hair analysis is an established field, but its testing regimen is set up for health checks that identify allergies, deficiencies and appropriate dietary supplements. In these circumstances, it doesn’t always work: third party checks on allergy tests revealed that results could not be reproduced, and the results of the tests weren’t up to the job of diagnosing an illness. A similar study into illegal and commonly abused drug metabolites in dogs found the tests were more reliable in some cases, but that false negatives did occur around specific drugs.
Evaluating these test results is a particular challenge since, as the American Society for the Protection of Cruelty to Animals explains, the majority of toxicology literature and guidance is based on human metabolism. Without a developed sense of the biology involved in doing a drug test with hair for dogs, it is harder for testing labs to understand the base state of the hair.
While the measurement of drugs in dogs’ hair can be useful in several scenarios, providing us with long-term, retrospective data on drug administration, we must be aware of its potential limitations. As with human hair, many different factors could influence the results of hair testing: hair growth rates, hair colour, environmental exposures, and more. Beyond this, the duration of the hair growth cycle as a whole, and the duration of the individual phases within it, varies between pedigrees, animals, and anatomical sites - whereabouts on the body the sample came from.
The analysis of dog hair samples could enable an extension of the detection period compared to urine, into the territory of drugs being present over several months. The interpretation of hair analyses concerning the date of a drug administration depends on the growth rate of the dog's hair, as well as incorporation of the drug due to sweat and sebum (an oily secretion from glands under the skin). It is not possible to verify an exact application date and the beginning of a repeated abuse; only a continuous presence of the drug over a period of time.
