Penn State and NAGP identify and reconstitute two lost Holstein lines

Artificial insemination (AI), breeding value estimation, and genomic selection have allowed substantial increases in milk and component yields for Holstein cows. However, their widespread use has also led to challenges including declining fertility, emergence of recessive genetic conditions, and a loss of genetic diversity—more than 99 percent of Holstein bulls born using AI in the last decade trace their male lineage to just two bulls born in the 1960s. Efforts to reconstitute two lost male lineages are reported in a recent article by scientists from the Pennsylvania State University Department of Animal Science and the National Animal Germplasm Program (NAGP), in the Journal of Dairy Science.