LA PAZ, Bolivia — A Bolivian court has upheld a government decision to seize a ranch from a U.S. cattleman and his family on the grounds they treated workers as virtual slaves, an official announced Monday The National Agrarian Tribunal rejected a challenge by Ronald Larsen, a 65-year-old from Montana who has owned the 58-square-mile (15,000-hectare) ranch nearly four decades, deputy land minister Juan Manuel Pinto said at a news conference. Pinto said the Caraparicito ranch would revert to Guarani Indians, traditional inhabitants of Bolivia's southeastern region, known as the Chaco. He said the ranch and an adjacent 15-square-mile (3,790-hectare)...