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.
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.
More top news
Getting back behind the controls after you've crashed the world's largest aircraft can be a little nerve-wracking.
There were "serious failings" in the anti-doping operation used at the Rio 2016 Olympic Games, a report by WADA has said.
The current and former First Ladies praised one another's record and experience - before criticising Republican Donald Trump on both fronts.