There is no question but what this subject matter is extremely complicated, and misconceptions are almost inevitable in the ideas exchanges. I think that most of us have a handle on the conception of F1 management in crossbreeding, but throughout this entire thread I have been looking for someone to mention that the 'fly in the ointment' - or - the 'stranger in the woodpile' is that old bug-a-boo HIGH QUALITY GENETICS, along with Phenotype and Functional traits!
Everyone has been citing "Breeds" in the matings, which is necessary for an understanding of results. BUT, ANY BREED CROSSING, whether it be crossing Breed A F1 Bull x Breed B purebred Cow - or - Breed A purebred bull to Breed B F1 Cow, has as it's Limiting Factors the differences in INDIVIDUAL QUALITIES of the individual animals being mated. If you would consider using the crossbred F1 Bull and a Herd of Purebred Cows - - the COWS would have to be PURE CLONES ( and that is a whole 'nother argument - ALLtogether :roll: ) in order to achieve a comparable genetic analogy, or comparison of relative values or appearances.
Very interesting debate! The work that Lee Leachman has done is in great depth and with several different breeds. A perusal of his work would be valuable for anyone seriously interested in deep crossbreeding with several different breeds (5 or 6 or 7 or more).
DOC HARRIS