Matt and Bendi Dunn, who operate Dunn Ranch, one of the nation’s most prominent Quarter Horse stables, announced on Thursday that they have temporarily ceased operating a stable at Los Alamitos in California. The decision comes at a time when Dunn Ranch has come under regulatory scrutiny for a series of positive tests found in some of its runners in major stakes in the fall of 2024. The stable has had two notable fatalities involving runners in leading races in recent months. In a statement released by Los Alamitos, Dunn Ranch said it will “pause its stabling, training and racing operations at Los Alamitos Race Course, effective immediately.” The statement said Dunn Ranch intends to resume racing at Los Alamitos in September. The announcement comes less than three weeks after the California Horse Racing Board issued a complaint against Dunn Ranch regarding 13 counts of medication violations found in tests taken from three of their runners after races or in out-of-competition testing in October and November of 2024. Dunn Ranch could face sanctions from the racing board for the infractions, pending a hearing. :: Access the most trusted data and information in horse racing! DRF Past Performances and Picks are available now. The horses – Ab Seis Corazones, American Dreamin, and Blood Viper – tested positive for the banned bronchodilator carmoterol, according to racing board documents. AB Seis Corazones tested positive after finishing second in the $763,000 Los Alamitos Super Derby on Nov. 10, 2024. In a ruling published by Los Alamitos stewards in March, Ab Seis Corazones was disqualified from the second-place finish, resulting in the forfeiture of $129,710. American Dreamin had three positives – in an out-of-competition test taken on Oct. 20, 2024, 15 days after a win in a time trial for the Golden State Million; after winning the $1.04 million Golden State Million final on Oct. 27; and in an out-of-competition test taken on Nov. 30, six days after a win in a division of the Los Alamitos Two Million Futurity trials. American Dreamin was disqualified from the win in the Golden State Million Futurity, resulting in Dunn Ranch forfeiting the first-place purse of $439,656, according to a ruling published in March. Blood Viper tested positive in an out-of-competition test taken 15 days after he finished second in a division of the Golden State Million Futurity trials on Oct. 5, 2024. Blood Viper was later promoted to fourth following the disqualification of American Dreamin in the Golden State final. No ruling has been issued regarding Blood Viper’s positive as of Friday. Three other Dunn Ranch-owned horses – Party Time Tom, Southern Divine, and Up to Party - were among eight horses that tested positive on 10 occasions for carmoterol in major races from February to September of 2024. Los Alamitos stewards ruled in December to disqualify those horses from purse earnings and for more than $1.03 million to be redistributed. As of Friday, the purses had not been redistributed. The cases are under appeal, according to a racing board executive. Party Time Tom finished second in the Governor’s Cup Futurity in July 2024; Southern Divine finished second in the Los Alamitos Oaks in March 2024; and Up to Party won two stakes in 2024 – the Ed Burke Million Futurity in June, and the Pacific Coast Quarter Horse Racing Association Breeders’ Futurity in September. The horses involved in the 2024 carmoterol positives were trained by Monty Arrossa, who was banned from Los Alamitos by track management last March for the positive tests. Following that decision, Arrossa’s assistant Ramiro Castillo took control of the stable. Castillo was banned from operating a stable by Los Alamitos management in December after five horses in his care died as a result of injuries sustained in races or because of illness in a six-month period from May to November last year. Two of those horses were owned by Dunn Ranch. At the time of his dismissal, Castillo was preparing two horses for the $700,000 Champion of Champions at Los Alamitos on Dec. 13. In the days before the race, they were transferred to trainer Luke Lindsey for the Champion of Champions. One of them, Stanley Cartel, owned by Dunn Ranch, sustained fatal injuries immediately after finishing sixth and could not be saved. Stanley Cartel was scheduled to go to stud this year. Last October, Warm Springs collapsed and died shortly after winning a division of the Golden State Million Futurity trials, according to the racing board’s website. The cause is listed as “sudden death.” In its one-page statement issued on Thursday, Dunn Ranch said it shared the track’s commitment to “equine safety, race integrity and fair competition. “We were concerned that over the past 20 months the performance of our California stable did not meet the high expectations we set for ourselves in regard to equine health and safety,” the statement read, in part. “The Quarter Horse industry has faced significant challenges over the past year, and like others, the Dunn Ranch has been the subject of regulatory matters that remain under review. We understand that these pending cases have led some in the industry to question our commitment to fair racing. By taking this unprecedented action we hope to demonstrate that we are committed to the highest standards of fair competition, racing integrity, and equine health and safety.” In its statement, Dunn Ranch indicated that it intends to undertake a “comprehensive review of our nutrition, treatment, racing and training practices and will be engaging independent experts to assist in efforts to ensure our program reflects the highest standards in the sport.” From 2021 through 2025, Dunn Ranch ranked in the top five nationally in Quarter Horse earnings. Dunn Ranch was second in the nation with earnings of more than $1.69 million last year. :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.