The U.S. government on Friday ordered testing of the nation’s milk supply for bird flu to better monitor the spread of the virus in dairy cows.Raw or unpasteurized milk from dairy farms and processors nationwide must be tested on request starting Dec. 16, the Agriculture Department said. Testing will begin in six states — California, Colorado, Michigan, Mississippi, Oregon and Pennsylvania.Officials said the move is aimed at “containing and ultimately eliminating the virus,” known as Type A H5N1, which was detected for the first time in March in U.S. dairy cows. Since then, more than 700 herds have been confirmed to be infected in 15 states.“This will give farms and farmworkers better confidence in the safety of their animals and ability to protect themselves, and it will put us on a path to quickly controlling and stopping the virus’ spread nationwide,” Agriculture Secretary Tom Vilsack said in a statement.The risk …