A loose bull on a stretch of Massachusetts highway led state troopers on a brief chase Monday morning after escaping from a farm. The bull was spotted Monday running loose on Interstate 495, near exit 10 in Norton. Massachusetts State Police closed lanes of traffic while troopers pursued the bull. A photo taken by a witness shows a trooper fleeing as the bull runs toward him. Police said the bull was corralled after several minutes of chasing and returned to the farm. It was unclear how the bull escaped from the farm.