The Bernese Mountain Dog (German: Berner Sennenhund) is a large-sized breed of dog, one of the four breeds of Sennenhund-type dogs from the Swiss Alps. Bred from crosses of Mastiffs and guard-type breeds, Bernese Mountain Dogs were brought to Switzerland by the Romans 2,000 years ago. The name Sennenhund is derived from the German Senne ('alpine pasture') and Hund (hound/dog), as they accompanied the alpine herders and dairymen called Senn. Berner (or Bernese in English) refers to the area of the breed's origin, in the canton of Bern. This breed was originally kept as a general farm dog. The age at onset for musculoskeletal problems is also unusually low. In the U.S./Canada study, 11% of living dogs had arthritis at an average age of 4.3 years. On July 1, 2010, the Bernese Mountain Dog became eligible to compete in AKC Herding Events. Herding instincts and trainability can be measured at noncompetitive herding tests. Berners exhibiting basic herding instincts can be trained to compete in herding trials.