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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Agricultural Genetic Resources Preservation Research » Research » Research Project #436326

Research Project: Regeneration of Y Chromosome in Holstein Cattle

Location: Agricultural Genetic Resources Preservation Research

Project Number: 3012-31000-006-22-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2019
End Date: Aug 31, 2024

Objective:
To regenerate a second generation of Holstein bulls derived from sons of repository bulls that have Y chromosome linkages not present in the in-situ population and thereby producing progeny that are competitive with industry standards.

Approach:
A cross involving high performance Holstein cows and unique Y chromosomes bulls was made. Genomic breeding values indicated the progeny were at breed average for the measure net merit. Making a second mating with the bull progeny and high producing cows will result in bull progeny which should rank in the upper 70th percentile, thereby making them competitive in the industry. Semen samples from the first bull progeny 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. Bull progeny will be transferred to a commercial AI stud for evaluation and potential use in their bull line-up. 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.