Princess Rooney, the champion older mare of 1984 and winner of the inaugural Breeders' Cup Distaff that same year, was euthanized Tuesday morning.
Princess Rooney suffered from complications of the disease equine protozoal myeloencephalitis, or EPM, which affects the central nervous system. She was 28.
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Princess Rooney had been on the Marquis medication course of treatment for EPM, but once the course of treatment ended, the daughter of Verbatim began going downhill again.
"What (the Marquis) ended up doing was slowing down the process, but it was still attacking the central nervous system and the muscles were deteriorating in her hind end," said Matt Howard, general manager of Gentry Brothers Farm, where Princess Rooney resided. "We had to make a decision because we didn't want her to go into any pain and suffering. Our fear was the muscles in her hind end would collapse and we didn't want her to be in pain that way. It's probably the hardest thing I've ever had to do."
Princess Rooney was one of the great racemares of her generation, winning 17 of 21 career starts including five Grade I races with a bankroll of $1,343,339. In her final career start, she demolished her foes by 7 lengths in the 1984 Distaff.
Her level-headed nature carried over into the breeding shed as she took on the role of stepmom for many of the weanling fillies at Gentry Brothers Farm, often teaching them manners even their human companions could not do.
"She took on the mother role with the weanling fillies and .... that is something we'll never be able to replace," Howard said. "She taught them more than a person could. We'd stick a weanling out with her and within a couple of weeks we knew we could go catch every one of them without them causing a fuss or anything.
"Not many people have the chance to be around a champion like she was. I was fortunate to be around her and see what a spectacular horse she was."
Howard said the farm was still working on burial plans for Princess Rooney.