Mandella with Omaha Beach Thursday morning.
Omaha Beach reportedly was coughing Wednesday morning, and an examination revealed an entrapped epiglottis - a breathing obstruction that compromises a horse's ability to breathe during exercise.
With that being said, Mandella didn't rule the horse out for the Breeders' Cup at the end of the year.
But that all changed Wednesday.
"A little bit of coughing caused us to scope him", Mandella said.
"It's not anything we can fix to have him run on Saturday, so we're going to have to scratch him", Mandella told The Form.
The scratch was another blow to cancer survivor Rick Porter, the colt's 78-year-old owner.
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However, doubts remain over his ability to lead Arsenal's rebuild back to the heights they once enjoyed under Wenger. And the defender hailed Ramsey's attitude since his move to Juventus was announced.
He has twice finished second in the Derby, in 2007 with Hard Spun and the following year with filly Eight Belles, who broke her ankles past the finish line and had to be euthanized.
Exercise rider Taylor Cambra rides Kentucky Derby entrant Omaha Beach during a workout at Churchill Downs Wednesday. The latest of Roadster's three victories came in the Santa Anita Derby on April 6. He'd ridden Roadster in all four of the colt's races.
Justify won the Kentucky Derby past year on his way to winning the Triple Crown.
Another reason I will be against the Wood Memorial victor is his connection's records in the Derby. "I feel awful for Richard and Mike".
Historically speaking, this is the most jarring Derby scratch since AP Indy bailed on the day of the race in 1992 due to a foot injury.
Beyond the Triple Crown, NBC Sports broadcasts some of the most important and prestigious events in all of horse racing.
According to Dr. Foster Northrop, an entrapped epiglottis can happen when the tissue beneath it has swollen and popped up, wrapping around the epiglottis and preventing it from moving as normal.