Project Number: 3012-31000-006-05-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 20, 2014
End Date: Jul 31, 2019
To regenerate Holstein bulls from repository samples that contain Y chromosome linages are not present in the in-situ population. Mate the resulting bull progeny to higher productivity cows/heifers to generate progeny that are within a standard deviation of breed average for milk production.
Based upon deep pedigree analysis repository bulls will be traced back to founding populations of Holstein cattle of which there are several male linages and therefore different Y chromosomes. The selected bulls will have semen samples withdrawn from the repository. These samples will be used for in-vitro fertilization, bull embryos will be identified and implanted into recipient cows. Resulting calves will be raised to sexual maturity when semen samples will be collected. Portions of the samples will be returned to the repository, which the remainder will be used to create another generation of cattle for evaluation. All progeny will be genotyped using the HD Bovine SNP chip (770K) for evaluation of Y chromosome and other issues related to genetic diversity, such as linkage disequilibrium.