Whether and how well a State's equine liability law protects you depends greatly on the state you are in. Some states offer significant protection (like NJ), others (PA) not so much. Now the law that applys to you. Make sure you comply every requirement. Have a good assmption of risk and release of liability. Get the right insurance. And, make safety a priority.
http://www.chronofhorse.com/article_landing/people%20%2526%20horses/legal