These dogs were crossed with European dog breeds, such as the Old English Bulldog in 1872, Mastiff in 1874, St. Bernard, German Pointer in 1876, Great Dane in 1924, and the Bull Terrier.
Disse hunde blev krydset med de europæiske hunderacer såsom Bulldog i 1872, Mastiff i 1874, St. Bernard, den tyske Pointer i 1876, Grand Danois i 1924 og Bullterrier.