(Reuters) - Two of Allergan Plc’s (AGN.N) shareholders - hedge funds Appaloosa Management and Senator Investment Group - on Tuesday asked the drugmaker’s board to split the role of chief executive officer and chairman, and end its acquisition strategy. Allergan, which has a market value of about $51 billion, is saddled with a long-term debt of $26.6 billion as of March end - an outcome of a string of acquisitions. The company’s shares have fallen about 33 percent in the past 12 months, up to Allergan’s close on Monday.