After a couple of lost training days last week because of escalating safety concerns with the dirt surface, racing resumed Monday at Thistledown, but another tragedy was not far behind. In the first race of the day, the 5-year-old mare Tayyara (Khozan) broke down and had to be euthanized. Thistledown canceled the remainder of the eight-race card. According to a Horseracing Safety and Integrity Authority (HISA) spokesperson, HISA Chief Executive Officer Lisa Lazarus asked Thistledown to cancel after the first race and they agreed to do so. She also asked...