SACRAMENTO- A thoroughbred died following an afternoon race at CalExpo, Thursday, July 18, 2013.

The mare, Reno Lucky Lady, had recently finished the fourth race and was being walked along the track to the barn. The horse's saddle and riding blanket had been removed. At the fourth turn, the horse collapsed and died right on the track. The death of the thoroughbred is being called a heart attack. 

Michelle Prater with CalExpo says the horse was taken to U.C. Davis Equine Center and will conduct a full necropsey to determine the exact cause of death. Result on the death of Reno Lucky Lady will be available in 24 hours.