A greyhound trainer was slammed when his dog tested positive for human antidepressants – after he claimed the animal drank his urine.

Neil Dempsie was found to have breached racing rules after a sample from his dog Peads Minx was found to contain venlafaxine – a medicine used to treat depression and anxiety – on two separate occasions.

He claimed that when he walked his dog, he would pee in the fields and then his dog licked his urine.

Campaigners against greyhound racing said the trainer’s excuse was “laughable” and further proof that dogs were often doped to either boost or suppress their performance.

A report from the Greyhound Board of Great Britain (GBGB) said urine samples from the dog, taken at Glasgow’s Shawfield stadium, tested positive for the drug.

It added: “Mr Dempsie said that he exercised the greyhound in an isolated field on his farm and that, while doing this, he would often relieve himself, urinating in the field.

“He suggested this was the likely explanation for samples testing positive”

Gillian Docherty, of Scotland Against Greyhound Exploitation, said: “Human antidepressants are used to slow the dog and affect the race outcome.

The positive tests were three months apart and yet the trainer claimed these were accidental.

“More laughable is that the regulatory body, the GBGB, has accepted this defence and given him merely a caution and he continues to race greyhounds.

“This is yet more evidence that the GBGB is not fit to regulate the industry and should be shut down.”

In September, greyhounds trained or racing in Scotland tested positive for banned drugs such as cocaine and amphetamine dozens of times.

Steroids, beta blockers and prohormones – used by bodybuilders – were among other prohibited substances found.

Five of the 28 positive tests at Shawfield – Scotland’s only licensed track – involved cocaine, which is potentially fatal for dogs and can lead to seizures, strokes and heart attacks.

The GBGB said they accepted Dempsie’s claims “based on irrefutable scientific evidence”. Dempsie was unavailable for comment at his home in Ayrshire.