By Lou Aguila (staff@latinospost.com) | First Posted: May 21, 2013 07:58 AM EDT

Trainer Mahmood Al Zarooni could be out from horse racing for a while after the British Horseracing Authority discovered seven more horses tested positive for anabolic steroid stanozol at his stable in Newmarket, England, the BHA confirmed on Monday.

The BHA already slapped the Godolphin trainer an eight-year ban, but this latest development dealt a major blow in Al Zarooni's appeal to lessen the severity of his suspension.

Al Zarooni admitted using anabolic steroids to his horses, though he was hopeful the BHA would consider his appeal while the case still pending.

"These test results endorse the swift action and measures taken by the BHA in this matter," BHA chief executive Paul Bittar told Reuters.

"Whatever the outcome of his appeal before the independent Appeal Board, the gravity and scale of the infringements warranted Mahmood Al Zarooni being removed from control of the yard as quickly as possible," Bittar added.

The BHA took blood samples from 391 horses at the stables of Al Zarooni and Saeed Bin Suroor. Bin Surror's horses were tested negative from steroid, allowing him to take over Al Zarooni Moulton Paddocks stable (subject to BHA clearance).

"No Separate action would be taken in respect of these additional positive results whilst Mr. Al Zarooni's appeal process is on-going. No date has been set for the appeal," BHA said in a statement.

The scandal has reportedly caused embarrassment to Dubai ruler Sheikh Mohammed bin Rashid Al Maktoum, whose horses are trained by both Al Zarooni and Bin Surror.

Appointed as the Godolphin's second British-based trainer in 2010, Al Zarooni won the world's richest horse race at the Dubai World Cup in March 2012. He followed it up with a victory at the St Leger with Encke at Doncaster six months later.

Encke was tested negative after the St. Leger race but hasn't competed in a race ever since the scandal broke out.