The Louisiana Racing Commission has begun an investigation into the ontrack euthanization of Grade 1 winner Monzante after the horse was apparently injured while running in a $4,000 claiming race Saturday night at Evangeline Downs. A 9-year-old gelding starting for the first time since November, Monzante made a move toward the leaders going into the far turn of the race over a mile and 70 yards but was pulled up by jockey Carlos Lozada at the eighth pole, a video replay of the race showed. The chart of the race, which noted that Monzante did not finish, says the horse was euthanized on the track. The winner of the Grade 1 Eddie Read Handicap in 2008, Monzante had steadily dropped down the class ladder over the past three years. He was claimed by Jackie Thacker for $10,000 out of a claiming race at Evangeline Downs on May 5, 2012, and made eight starts that year for his new owner-trainer but had not started since Nov. 23 prior to Saturday’s race. Thacker did not respond to a voice-mail message Monday. So far in 2013, according to Equibase records, Thacker has had 41 starters, with 5 wins, 4 seconds, and 3 thirds. Attempts to reach Lozada were unsuccessful. Charles Gardiner, executive director of the Louisiana Racing Commission, said the commission launched the probe into the horse’s death following a number of inquiries directed toward the regulatory agency since Sunday night, when several online commentators publicized the horse’s death while noting his rapid drop in the claiming ranks. Gardiner said that every horse entered to race at Louisiana tracks is required to pass a veterinary examination. He said Monday that the commission had not yet gathered information about the specific injury suffered by Monzante, nor had it been able to review the horse’s veterinary records, but that the commission was seeking that information as part of its probe. “We’re gathering the facts right now,” Gardiner said. “If there’s any mistake on our end, we want to know so that we can fix it.” Monzante was entered in a $5,000 claiming race at Evangeline Downs on June 8 but was scratched by the veterinarian, according to charts of that day's card. Evangeline Downs is one of dozens of major U.S. Thoroughbred racetracks that are not accredited by the National Thoroughbred Racing Association Safety and Integrity Alliance, which certifies tracks based on their adherence to safety and welfare policies, including their criteria for passing veterinary examinations. Mike Ziegler, executive director of the alliance, said Monday that Evangeline has not applied for accreditation since the program was launched late in 2008 with pledges from 55 tracks. The initial pledge list did not include Evangeline, and only 25 tracks have applied for accreditation since the program’s launch. Evangeline Downs is owned by Boyd Gaming, a casino company. Like all other racetracks in Louisiana, purses at Evangeline are heavily subsidized by slot machines. Saturday’s $4,000 claiming race had a purse of $8,000. Monzante was bred by Juddmonte Farms, which raced the horse six times in England before selling him through a horses of racing age sale in 2007. The horse changed hands three times in the past two years as a result of claims, once for $20,000 and twice for $10,000. He made 43 career starts, with eight wins and $583,929 in earnings. Monzante’s drop down the claiming ranks illustrates a common career path for many aging horses, especially geldings, which have no reproductive potential. According to data collected through the Equine Injury Database, horses ages 4 and older are at greater risk of catastrophic breakdown than 2-year-olds or 3-year-olds, and horses running in claiming races are at higher risk than horses who are not running in claiming races. The data also have indicated that geldings have a lower risk of suffering a catastrophic breakdown than intact males. Approximately 710 Thoroughbreds died of catastrophic injuries at U.S. tracks in 2012, according to the data, which include the results from tracks representing more than 90 percent of all starts in the United States. The death of Monzante appeared to have struck a sonorous chord inside and outside the racing community by Monday afternoon. On Sunday evening, an online petition drive was launched asking the NTRA to investigate the death, even though the NTRA has no regulatory authority or investigative capabilities. The petition had been signed by more than 500 people by Monday afternoon. In addition, a Twitter handle called “Project Monzante” was launched with this description: “Because there should be no more Monzantes. A fan effort to track the old warriors, to change racing culture, and to get involved in Thoroughbred retirement.” Though predating the age of social media, the discovery in 1997 that the former champion racehorse Exceller had been sent to a slaughterhouse galvanized a movement to ban the slaughter of racehorses and to provide retirement homes for ex-racehorses. The movement gained steam when it was discovered in 2003 that former champion Ferdinand also was sent to slaughter, leading to federal efforts to ban horse slaughter in the United States. In a previous version of this article it was incorrectly stated that Monzante was claimed out of a race at Fair Grounds in May of 2012. He was claimed out of a race at Evangeline Downs.