Jockey Club report: Fatal injury rate twice as high on dirt as on synthetic in 2011

Horses running on dirt surfaces were nearly twice as likely to suffer a fatal breakdown as a horse running on an artificial surface in 2011, according to data released on Thursday by the Jockey Club as part of an ongoing project to collect information on racing injuries at North American racetracks.

The fatality rate for horses running on traditional dirt surfaces was 2.07 per 1,000 starts during 2011, according to the data. The rate on artificial surfaces was 1.09 per 1,000 starts, an 89.9 percent difference. The rate for turf surfaces was 1.53 per 1,000 starts.

The rate for dirt surfaces was calculated from 283,745 starts, whereas the rate for artificial surfaces was calculated from 45,700 starts. The Jockey Club has said that racetracks representing 93 percent of the starts in North America are currently supplying injury data to the project, which was launched late in 2008.

Counting fatalities on turf surfaces, the overall rate for catastrophic injuries in 2011 at North American racetracks was 1.88 per 1,000 starts, equal with the overall rate in 2010 and a slight improvement over the fatality rate of 1.98 for 2009.

Last year, the Jockey Club had reported slightly higher overall rates for catastrophic injuries in 2009 and 2010 than it reported on Thursday. The Jockey Club, however, said in a release accompanying the data that it had changed the reporting requirements for a racetrack fatality to reflect only those horses that died within three days of suffering injuries. The vast majority of fatalities occur within 72 hours of the initial injury – for 2011, for example, racetracks reported 758 fatalities, and all but 44 occurred within the 72-hour window.

“We realize there are situations in which the outcome is not determined until much later than 72 hours after an incident, but our confidence level in reporting an accurate benchmark statistic is greatest when we utilize information available within 72 hours,” said Matt Iuliano, the executive vice president of the Jockey Club, in a statement.

Veterinary experts and epidemiologists caution that racetrack injuries are usually the result of multi-variable factors and that a focus on one factor, such as racing surface, can be misleading. However, the fatality rate for horses running on artificial surfaces has declined markedly over the past three years, and a similar decline has also been registered for turf racing. The declines have widened the gap between the rate for the two surfaces and the rate for dirt racing.

In 2009, the rate on artificial surfaces was 1.49, well below the 2.1 rate on dirt surfaces. In 2010, the rate for artificial surfaces fell to 1.21, compared to the dirt rate of 2.05. Similarly, the turf rate was 1.87 in 2009 before falling to 1.59 in 2010.

Last year, Dr. Tim Parkin, an epidemiologist hired by the Jockey Club to analyze the data, said that the difference between the dirt rate and the artificial rate had become statistically significant for the first time, meaning that statisticians would have confidence in saying that horses suffer fatal breakdowns on artificial surfaces less often than on dirt because of factors that do not include anomalies in the underlying data.

The data for 2011 released on Thursday also included break-outs by age, sex, and distance.

◗ By age, 2-year-olds suffered fatalities at a rate of 1.20 per 1,000 starts; 3-year-olds, 1.98; and 4-year-olds and up, 1.92.

◗ By sex, males, 1.97 per 1,000 starts; females, 1.76.

◗ By distance, less than six furlongs, 2.17 per 1,000 starts; six furlongs to 7 ½ furlongs; 1.77; and one mile or farther, 1.80.

The database project was launched late in 2008 in order to gather information on racehorse injuries in an attempt to identify risk factors while racing. Bob Curran, a spokesman for the Jockey Club, said that an analysis of the data for underlying factors is “ongoing.”