Hybrid vigor in dairy herds by crossing in breed
W. A. Regan
California Agriculture 1(5):1-2. DOI: 10.3733/ca.v001n05p1b.
Not available – first paragraph follows:
The generally accepted explanation of hybrid vigor or heterosis in dairy cattle is based on the fact that most of the desirable hereditary factors tend to be dominant, while those less desirable are often recessive or hidden.