The British Horseracing Authority's suspensions effectively rule out all 15 of Godolphin's injected horses for the entire campaign with just four and a half weeks left of the season on their return.
The racing body confirmed the punishment and explained the length of the ban:
The BHA has today informed Godolphin, the owners of the horses in question, that the 15 horses known to have been administered with either Ethylestranol or Stanozolol have been suspended from running in races for a period of six months, with effect from Tuesday, April 9, 2013.
The length of suspension reflects the period beyond which the BHA is confident that the horses in question can have derived no performance related benefit from the administration of these prohibited substances.
– Jamie Stier, the BHA's director of raceday operations and regulation
Certify, which ended 2012 unbeaten in four runs, was one of seven horses to test positive for Ethylestranol while Opinion Poll was one of four whose blood was found to contain Stanozolol.
Godolphin trainer Mahmood Al Zarooni will stand before a disciplinary panel of the British Horseracing Authority later today after samples taken from 11 of his horses were found to have contained traces of anabolic steroids.
Al Zarooni could lose his training licence in one of the most significant doping scandals in recent racing history. The hearing is due to be held this lunchtime in central London.
The 37-year-old has officially been charged with rule breaches related to prohibited substances, duty to keep medication records, and conduct prejudicial to racing.
I have ordered the Godolphin management to undertake an immediate review of our internal procedures and controls to ensure to prevent any reoccurrence of this type of activity in any stables of mine.
We will be locking down the Moulton Paddocks stables with immediate effect, and I have instructed that I want a full round of blood samples, and dope testing done on every single horse on that premises.
I can assure the racing public that no horse will run from that yard this season until I have been absolutely assured by my team that the entire yard is completely clean.
Sheikh Mohammed has issued a statement saying he was "appalled and angered to learn that one of our stables in Newmarket has violated Godolphin's ethical standards" in the wake of trainer Mahmood Al Zarooni being charged by the BHA after 11 of his horses tested positive for anabolic steroids.
The British Horseracing Authority has said that information provided by Godolphin trainer Mahmood Al Zarooni to investigating officers revealed that in addition to the 11 horses which had initially tested positive for anabolic steroids:
Four other horses Comitas, Sashiko, Vacationer and Tearless - were administered one of two prohibited substances - Ethylestranol or Stanozolol.
Those horses were under the care of the Newmarket trainer, but had not been subjected to testing.
Although these horses were not tested and no positive samples exist, Al Zarooni faces further charges in relation to medication records and conduct prejudicial to racing.