(CNN) -- One of the world's most successful horse racing operations has undergone a major reshuffle in an attempt to close the stable door on a damaging doping scandal.
The changes come after the publication of a report into Sheikh Mohammed bin Rashid Al Maktoun's Godolphin stable, which criticized "management failings, insufficient oversight and complacency."
The report was commissioned by Sheikh Mohammed -- the ruler of Dubai -- after Godolphin's former trainer Mahmood Al Zarooni was banned by the British Horseracing Authority (BHA) in April 2013, having been found guilty of administering anabolic steroids at the operation's stables in Newmarket, England.
In the reshuffle, Godolphin's long-standing racing manager Simon Crisford has resigned, though he will take up a new role as a racing adviser to Sheikh Mohammed
With the position of racing manager no longer existing, responsibility for horses will be devolved to trainers Saeed bin Suroor of Al Quoz Stables and Godolphin Stables and Charlie Appleby of Moulton Paddocks and Godolphin Marmoom Stables.
"They will be the people ultimately responsible for their particular stables; they hold the delegated authority of the owner as defined by the condition of their license," said a Godolphin statement.
Al Zarooni is serving an eight-year ban after 22 horses tested positive for anabolic steroids. The BHA has also banned 15 horses trained by the 37-year-old for six months.
Sheikh Mohammed was cleared of any wrongdoing by former Metropolitan Police commissioner John Stevens' report, which concluded that Al Zarooni had acted alone in the doping scandal.
"Having dealt with the events of last year and seen the Lord Stevens inquiry through to its conclusion, I thought that this was a good moment to bring my time at Godolphin to a close," Crisford, who has been Godolphin's manager since the stable was created over 20 years ago, told the Racing Post.
"I had felt for a while that I would like a fresh challenge. I think the time is right for a new start for the stable and for me.
"Sheikh Mohammed has asked me to take on a new role as his global racing adviser. I am delighted to have accepted that position and I am very much looking forward to what will be an exciting new chapter for me."
Godolphin has won more than 200 Group One races in different countries since Sheikh Mohammed established training operations in Dubai and England in 1992.