Senepol were developed on the Caribbean Island of St. Croix by Henry C. Nelthropp in the early 1900's by crossing Red Poll cattle and N'Dama cattle. The Senepol breed combines the N'Dama characteristics of heat tolerance and insect resistance with the extreme gentleness, good meat, and high milk production of the Red Poll. He selected for early maturity and maternal efficiency, no horns and solid red color, definite heat tolerance, and gentle disposition.
The isolation sheltered the cattle from the fads and fancies of the purebred seedstock industry. While other breeds made giant leaps in one direction, only to turn and make equally large strides in the opposite direction, the Senepol made a series of small, multiple-trait steps toward animals whose production met the demand of their breeders.
St. Croix provided a unique situation where ranchers practice selection for the traits they desired and mother nature provided natural selection for cattle that could produce at superior levels under the harsh St. Croix environment.