Racehorses Are Dropping Dead in California 17 confusing deaths since July By Mark Russell, Newser Staff Posted Apr 11, 2013 9:33 AM CDT 45 comments Comments Two horses racing at the California Breeders Champion Stakes on Saturday, Jan. 26, 2013, at Santa Anita Park in Arcadia, Calif. (AP Photo/Benoit Photo) (Newser) – Racehorses that die in California are subject to one of the country's most comprehensive post-mortem reviews, and what those reviews are finding—or not finding—is unsettling. Racehorses have been dropping dead in the state, and no one knows why, reports the New York Times. Nineteen died in in the year ending June 30, 2012; 17 have died so far this fiscal year. But so far authorities only know that necropsies have found evidence of "acute respiratory distress." "We have not been able to find the cause," says a vet with the state's Animal Health system. "We have done extensive toxicological studies. We have done, of course, all sort of other things—pathology and histology. We don’t know what’s going on." Sudden deaths are typically rare in thoroughbreds; to wit, just 9% of racehorse deaths in the state in 2010 were of this type. The California-focused story follows a Times investigation last year that found 24 horses die each week on the country's racetracks, and which painted a picture of an industry in which drugs are ample and regulation is in short supply.