The 2013 Gold Cup winner, which placed second in the same race this year, has tested positive for opioid morphine, a prohibited substance.
A statement by the palace indicates the five-year-old filly’s positive test result had stemmed from the “consumption of a contaminated feed product”.
It’s believed Her Majesty, 88, – who was present to cheer on the horse on to victory at Royal Ascot last year – was told the news at her great-grandson Prince George’s first birthday.
The Mirror reports a statement by the Queen’s Bloodstock and Racing Advisor, John Warren, said the British Horseracing Authority (BHA) informed the Palace that five horses from a number of different trainers tested positive for morphine.
He said: “I can confirm that one of those horses was Estimate, the five-year-old filly trained by Sir Michael Stoute and owned by The Queen. Initial indications are that the positive test resulted from the consumption of a contaminated feed product.
“Sir Michael is working closely with the feed company involved to discover how the product may have become contaminated prior to delivery to his stables.
“As the BHA investigates this matter, including potential links between the different cases, Sir Michael continues to offer his full co-operation.
“There will be no further comment until the BHA announces its considered findings. Her Majesty has been informed of the situation.”
While the levels of drugs detected have not been released, the BHA is known for a stringently low threshold for opiates, bordering almost on zero tolerance.
Jamie O’Gorman, a veterinary surgeon wrote a piece for the UK’s Telegraph about horses testing positive and in it he stated that it is unlikely Estimate would have benefitted from using morphine to race.
He wrote: “As far as I know [morphine] is never used for performance enhancement although, like a lot of these drugs, it would be hard to prove one way or another if it enhanced performance in the right quantities.”
“The culprit in these situations is usually found to be rogue poppy seeds, which have found their way into the crops used for the feed,” O’Gorman added.
The Queen is presented with the 2013 Gold Cup by her son, Prince Andrew.
Estimate made sporting history last year when it won at Royal Ascot and made her Majesty the first reigning monarch to own the Gold Cup winner.
At the time Sir Michael said the Queen was “thrilled” with her filly’s triumph.
He told the Mirror: “It’s a special thrill to win this race for the Queen and it will have given her enormous pleasure – she really loves this game and it’s a great recreation for her.
The Queen won £155,960 in prize money as the racehorse owner.
