But this month, the 4-year-old dark bay took a turn for the worse. There were two procedures to remove damaged tissue from his left hind hoof, the site of his laminitis. On Jan. 13, a cast was placed on his right hind leg for more support.
On Saturday, with the horse foundering, Richardson performed a third surgery on the right hind leg. Barbaro had developed an abscess in the hoof as a result of the continuing laminitis problem in the left.
Richardson inserted two steel pins in one of the three bones that had healed since May to eliminate all weight bearing on the right hoof. The cast was replaced by an external brace, or skeletal fixation device.
The last-ditch attempt was not enough. Yesterday morning, there were signs of laminitis in Barbaro's two front legs.
"It was a difficult decision to make, but it hinged on what we said all along," Richardson said. "It was about his quality of life and whether we had any reasonable expectation of saving him.
"In the last 24 hours, he developed fairly severe laminitis in both front feet that left him not a good leg to stand on."
Throughout the days of hopeful reports from New Bolton, often followed by words of caution, the horse racing community understood just how much of a long shot it was for Barbaro to recover completely.
Dick Small, a veteran Maryland trainer, said: "There were so many people rooting for him after he was injured, but it was sort of like hoping for a miracle, like in church. They just don't happen very often."
To an extent, the horse's dramatic fight for survival obscured his impressive accomplishments on the track.
"It'd be nice if he's remembered for winning the Kentucky Derby, not for breaking down in the Preakness," Peter Brette, Barbaro's exercise rider and assistant trainer, told the Associated Press.
Given Barbaro's Kentucky bloodlines, his success was not a surprise. His sire was Dynaformer, out of the mare La Ville Rouge. Dynaformer was bred for distance, La Ville Rouge for speed. Together they won 13 races and nearly $1 million.
Barbaro earned $2.2 million for his six victories. He started his career in October 2005, as a little-known colt, winning at Delaware Park and Laurel Park.
It was Barbaro's half-length victory in the Florida Derby in April that raised his profile for the Triple Crown series and the Kentucky Derby.
In Louisville, he stunned the racing world with the Derby's fastest final quarter-mile since Secretariat in 1973. He won by nearly seven lengths in a 20-horse field.
Before the Preakness, trainer Michael Matz said: "The biggest thing Barbaro has going for him is his will to win, his heart."
Barbaro proved that at Pimlico. He broke through the starting gate prematurely but was quickly brought up. On the second try, calamity struck.
Less than 200 yards into the race, Barbaro wobbled in obvious pain. Only jockey Edgar Prado's quick action to rein him in saved the horse from immediate destruction.
"[Barbaro] knew he was hurt and he relaxed for me," Prado said.
As Matz tended to Barbaro on the track, Pimlico fans screamed, "No! No! No!" and "Don't you kill that horse!"
Barbaro was sent by van to New Bolton Center, where a team of seven inserted a titanium plate and 27 screws to piece the leg together.
"It's not about money," Gretchen Jackson said at the time. "It's not about limelight. It's more about the horse and its beauty and integrity on a lot of levels."
Roy Jackson reiterated that sentiment yesterday, saying, "There is nothing we would have done differently."
Sun reporters Kent Baker and Mike Klingaman contributed to this article.