Greger went to college at Cornell University School of Agriculture, where as a junior he wrote informally about the dangers of bovine spongiform encephalopathy on a website he published in 1994.[2][3][4] In the same year he was hired to work on mad cow issues for Farm Sanctuary, near Cornell, and became a vegan after touring a stockyard as part of his work with Farm Sanctuary.[2] In 1998, he appeared as an expert witness testifying about Bovine spongiform encephalopathy when cattle producers unsuccessfully sued Oprah Winfrey for libel over statements she made about the safety of meat in 1996.[2][5]