The Thoroughbred Safety Committee of the Jockey Club is scaling back a safety recommendation in light of new evidence from racetracks.The committee previously recommended that the cleat-like horseshoe extensions known as toe grabs be no longer than 2 millimeters in order to reduce horse injury. Longer toe grabs have been shown to increase the risk of injury by causing a buildup of dirt on horseshoes, and that evidence inspired the 2 millimeter limit.But the Delaware Thoroughbred Racing Commission recently found that the shorter grabs increased stumbling with some horses.Thoroughbred Times writer Ed DeRosa says he's not surprised that new evidence caused more changes."There's a lot of variables you can test for, but until you actually get into real racing conditions where you have full fields of 8 to a dozen horses including a starting gate and a jockey on your back, all those variables are hard to replicate in a test situation," he says.The safety committee is now recommending that toe grabs be no longer than 4 millimeters.