Curlin, at 22 one of the most influential stallions in modern history, will not cover any more mares during the 2026 breeding season after a brief illness, said Hill 'n' Dale at Xalapa owner John Sikura Wednesday afternoon.“Curlin, about 10 days ago, exhibited some discomfort,” said Sikura. “Dr. (Nathan) Slovis from Hagyard examined him and found an ulcer which was outside of his stomach,” said Sikura. “This is highly unusual. He exhibited symptoms of pain, we treated him, and he had three days off breeding mares. He had a mild temperature, but nothing significant. When he was off all medication, he returned to the breeding shed, and had great libido covering mares, but his dismount samples did not look great.”Sikura said that when his most recent mares were not checked in foal, Dr. Dickson Varner, a renowned stallion reproductive expert from Texas A&M, came to see him. “Dr. Varner came today, examined his dismount sample, and found it subnormal in motility and the number of live semen. Based on the science of how the body produces a sperm cell to a viable ejaculate, we thought it was only fair to give the horse a chance to regenerate on his own, and not to cover mares, which wouldn't be fair to outside breeders or to syndicate members.”Sikura said the farm is hopeful that Curlin will be able to return to service in 2027.“Obviously, that's not guaranteed,” Sikura said. “How close he will come to normalcy, time will tell, but it's still April, and everybody has a chance to regroup. Once we knew that it was unlikely for him to continue to get mares in foal, it was determined at the advice of veterinary experts to have the rest of the year off. This is a huge loss for us, but we respect the horse, are treating him with dignity and treating our customers fairly.Curlin, known for siring classic, two-turn dirt horses, stood for $225,000 in 2026. He was the first sire to have three winners on a single Breeders' Cup card, which he achieved in 2022 with Malathaat, Elite Power, and Cody's Wish. He has twice sired three champions in a single year, which he did back-to-back in 2022 and 2023.“It's a tough day for Hill 'n' Dale, said Sikura, “but we'll do what's best for him and see what the future holds for him. We have always bred some of our best mares to him, and we're in the same situation as everybody else. We bred Cavalieri (Nyquist) to him last week.”Sikura said that Curlin has over 20 mares checked in foal this year, and that mares were still being checked. “He was a normal horse prior to this incident,” he said. “There is an accumulation of issues in an older horse, and those stress factors have compromised him. There's not a direct, specific diagnosis. These things are somewhat mysterious at any stage, but with older horses, they're more susceptible to illness and injury, elevated temperatures, and treatment. Hopefully he can regroup and cover mares next year. But it's the right decision to make at this time.”Sikura acknowledged that breeders with top mares may find it hard to find another elite-level stallion with room left in their book. “It's a difficult situation because so many of those stallions at that level are full,” he said. “We're going to make a special exemption to let people book mares to Good Magic, and do everything we can do to help our customers.”He said that Barbara Banke, who campaigned Curlin with her husband Jess Jackson in their Stonestreet Stables, strongly supported the decision to take the rest of the season off.“Barbara Banke agrees with the decision,” said Sikura. “It has always been her wish that we take care of all the stallions ahead of any economic purpose. She loves the horse. We've always managed him very carefully. It's a real milestone for us to stand one of the couple of best stallions for more than a decade. That's a real honor. Means a lot to us and our sense of pride. It's hard to feel sad because at the same time, you have to realize how blessed you have been.”The post After Ulcer, Fever, Curlin Won’t Breed More Mares in 2026 appeared first on TDN | Thoroughbred Daily News | Horse Racing News, Results and Video | Thoroughbred Breeding and Auctions.