Irish trainer Stephen McConville and his son Michael have been disqualified for three years after admitting to injecting a substance later found to contain cobalt into Anseanachai Cliste at the Cheltenham Festival.

Anseanachai Cliste was withdrawn from the Foxhunter Chase in March when syringes were found in a bag taken to the course.

Both the trainer and his son, the owner of the horse, pleaded guilty to the administration, or conniving in the administration of prohibited substances on a race day.

Michael McConville also had to answer whether he failed to act in the interests of the horse's best health and welfare by administering substances, namely Adrenal Cortex, without veterinary consultation or advice.

In a statement to Press Association Sport, the McConvilles accepted full responsibility and apologised for the incident, saying they were unaware one of the substances they gave the horse contained cobalt for which Anseanachai Cliste tested seven times above the threshold.

"We fully accept the finding of the British Horseracing Authority and regret that they had to invest time and resources to investigate and address the incident," the statement said.

"We apologise for what has happened, which was of our own doing due to lack of knowledge. However, this is no excuse for what happened at Cheltenham.

"The horse was administered the tonic - Hemo 15 - which is a widely used nutritional supplement which, unknown to us, contained cobalt."

Anseanachai Cliste had won eight successive point-to-point races before Cheltenham and went on to win the Ulster National at Downpatrick nine days later.

The early admission of the pair meant the disqualifications were reduced from five years for Michael McConville and from four years for his father.

The BHA has emphasised the use of cobalt is a threat it is taking seriously.

"The BHA has been part of international collaboration and research regarding cobalt, which resulted in internationally adopted raceday thresholds of 0.1 micrograms total cobalt per millilitre in urine or 0.025 micrograms per millilitre in plasma, these have been embedded into the rules of racing," the BHA said.

"The presence of cobalt above the internationally accepted threshold is prohibited in British Racing. Whilst cobalt is an essential trace element and is naturally present in the horse, it may also have the potential to enhance performance when present at concentrations that exceed normal physiological parameters.

"It is also possible that exposure to significantly increased levels of cobalt may have welfare implications for the horse."