Steve Coburn, the co-owner of California Chrome, issued an emotional apology Monday for his bitter reaction to his horse's defeat in Saturday's Belmont Stakes that cost him his chance for the Triple Crown.

Accompanied by his wife Carolyn, Coburn fought back tears as he apologized for calling the connections of the winning horse Tonalist "damned cheaters" and "cowards".

"Very ashamed of myself," Coburn told Good Morning America. "Very ashamed. I need to apologize to a lot of people, including my wife Carolyn.

"First of all, I need to apologize to the winners. They ran a beautiful race. Their horse won the race. They deserve that.

"I did not mean to take anything away from them so I want to apologize to everyone associated with Tonalist... he won the race fair and square, he deserved the win."

Coburn also apologized to his co-owner Perry Martin and California Chrome's trainer Art Sherman and the thousands of fans who were captivated by their horse's fairytale success.

Bred for a pittance by two working-class men new to a sport usually dominated by the rich and famous, California Chrome defied the odds when he won the Kentucky Derby then the Preakness Stakes.

He had the chance to become the first horse in 36 years to complete the elusive Triple Crown, which includes the Belmont Stakes, and join one of the most elite clubs in United States racing, alongside immortals such as Secretariat, Citation and Seattle Slew.

But like so many other great horses who have won the first two legs but found the extra distance of the Belmont Stakes too much after an exhausting build up, California Chrome could only manage a tie for fourth place.

But Coburn, who had become a media hit with his trademark cowboy hat and brash predictions that his horse was certain to win every race, did not take the loss well and launched into a bitter attack on his rivals immediately after the Belmont.

Coburn was angry that many of the horses that ran in the Belmont, including Tonalist, had not run in the two previous legs of the Triple Crown, even though it is a long established and accepted part of the rules and one of the integral hurdles of the Triple Crown challenge.

He called them cowards and cheaters and despite being branded a sore loser, Coburn continued his tirade the following day, likening the rules to a grown man playing basketball against a child in a wheelchair, an analogy that drew wider condemnation.

But by Monday, Coburn, a factory worker in Nevada, had a change of heart, saying he had been caught up in the emotion and being thrust into a situation he had never experienced before.

"I wanted so much for this horse to win the Triple Crown for the people of America and I was very emotional," he said. "It's just the emotion of the whole journey coming all together at one time.

"It's a learning process for us and I'm going to do better. ... I needed to do this (apologize), I needed to do this because I was wrong."

His wife Carolyn said California Chrome would resume racing again later this year after taking a break and she hoped the horse's fans would forgive her husband for his outburst, which she said was out of character.

"I'm proud of him for coming up here (on TV) and doing this. It was something we needed to have done," she said.

"This horse and our story has given so much joy to so many people. I hope that this 30 seconds isn't going to destroy all that."