Heat and humidity can be a killer, but when is it too hot to run?
During a summer with extreme temperatures at both ends of the state, California racing authorities may institute a new policy mandating heat restrictions for horse safety.
The day after a 2-year-old filly died following a race at the State Fair, the California Horse Racing Board's Medication and Track Safety Committee took the first step Friday in potentially establishing guidelines with a hearing on when it's safe to race on days with high temperatures.
Triple-digit temperatures are forecast for today and Sunday, the final two days of the State Fair meet.
California racetracks don't have a statewide policy on heat and racing. Other racing venues and equestrian events use the Heat Stress Index of 180 as the limit to allow competition, said Dr. Rick Arthur, the CHRB's state veterinarian. The state will use 180 as an unofficial guideline for now.
"Because we don't have high humidity in California, we seldom exceed (180)," Arthur noted. "Some veterinarians have advocated for a lower threshold."
The Heat Stress Index adds temperature and percentage of humidity. For example, 100 degrees plus 50 percent humidity equals 150 on the heat index.
"A horse starts losing its ability to dissipate heat above 130 on the Heat Stress Index," Arthur said. "The closer you get to 180, the more problematic it becomes to get a horse cooled out."
Typically, ice buckets and water hoses are used to help heat-stressed horses.
"Horses are like humans; they sweat," Arthur said. "Putting water on them is a very effective way to help them lower the heat."
Thursday's conditions at Cal Expo appeared to be within those limits. The temperature reached 99 degrees with 32 percent humidity for a heat index of 131.
Reno Lucky Lady, a 2-year-old filly making her first career start for trainer Steve Sherman, collapsed and died after Thursday's fourth race. A $26,000 purchase by Nevada Equine, Reno Lucky Lady was the most expensive filly sold at the 2012 Northern California Yearling Sale.
Results of a necropsy at UC Davis won't be available for a few days, Arthur said.
"It's very hard to determine exactly if heat or some other related problem was the cause, but from preliminary discussions, it looks like heat was a factor," Arthur said. "Obviously, it was within reasonable limits on the heat index for horses to race."
For the State Fair meet, Cal Expo has taken several precautions to keep horses and riders safe, said racing director David Elliott.
"We're very serious about jockeys and horses having everything they need to make them comfortable," Elliott said. "The weather is the same for both.
"For the horses, we have big misters in the paddock and lots of coolers full of ice. We've run lots of hoses (to the track) and have water available to try to cool horses down."
Elliott said Cal Expo uses additional precautions when the heat index reaches 150 and would consider canceling races in extreme heat.
Most of the horses competing at the State Fair ship from cooler Bay Area facilities such as Golden Gate Fields in Albany. That change in temperature can affect horses, too.
"Oftentimes, an animal may not be acclimated to a (higher) temperature," Arthur said. "They're not adjusted to the heat."
Call The Bee's Debbie Arrington, (916) 321-1075. Follow her on Twitter @debarrington.