Champion mare Typhoon Tracy has died while giving birth to her first foal at Vinery Stud in the NSW Hunter Valley.
Vinery confirmed the 2010 Australian Horse of the Year had died suddenly, shortly after producing a healthy colt by Street Cry.
"The family has been with us for a long time and this is an extremely sad morning," Vinery's Peter Orton said.
"Tracy passed away quietly following a straightforward foaling from a suspected ruptured broad ligament.
"Typhoon Tracy's dam Tracy's Element, now 22 years of age, was born and reared here and has been an integral part of the farm for years.
"This is an extremely sad morning for (owners) the Hutchins family and the stud."
Trained by Peter Moody, Typhoon Tracy was retired from the track following her victory in the 2011 Orr Stakes, her sixth Group One win.
She won 11 of her 20 starts and earned more than $2.4 million.
Typhoon Tracy was crowned 2009-2010 Australian Racehorse of the Year for her Group One wins in the 2009 Myer Classic (1600m) at Flemington, the 2010 Orr Stakes and 2010 Futurity Stakes (1600m) at Caulfield and the 2010 Queen Of The Turf Stakes (1500m) at Rosehill.
Moody, Victoria's leading trainer, paid tribute to Typhoon Tracy.
"She was basically the first banner horse we had," he told Melbourne's RSN radio.
"The thing about her was her wonderful nature.
"Everyone here at the stable this morning is very moved by it (the death).
"Even the vet said he'd never worked on a horse with such a beautiful nature."
Moody said it was one of the great regrets of his career that he didn't run her in the 2010 Cox Plate.
"We aimed her at it and then we jigged at the last minute and ran into a heavy track on Derby Day and got beaten," he said.
"It's one of my real regrets not forcing the issue to run her in the Cox Plate that year."