Amanda Loyola, a 15-year-old Upper West Sider, won third place in OppenheimerFunds/NFTE National Youth Entrepreneurship Challenge last month. Loyola, a student at the Horace Mann School, will receive $2,500 to fund her vegetarian dog treat business. Loyola came up with the idea after her dog Princess died of cancer two years ago. She discovered that red meat, which contains chemicals from cattle feed, was one of the leading causes of cancer in dogs. During the summer of 2007, Loyola attended NFTE BizCamp and created a plan to sell vegetarian dog treats. She took first place in the New York Metro competition and went on to compete against 35 students from across the nation in October.