Changes in genetic selection differentials and generation intervals in US Holstein dairy cattle as a result of genomic selection

Seven years after the introduction of genomic selection in the United States, it is now possible to evaluate the impact of this technology on the population. Selection differential(s) (SD) and generation interval(s) (GI) were characterized in a four-path selection model that included sire(s) of bulls (SB), sire(s) of cows (SC), dam(s) of bulls (DB), and dam(s) of cows (DC). Changes in SD over time were estimated for milk, fat, and protein yield; somatic cell score (SCS); productive life (PL); and daughter pregnancy rate (DPR) for the Holstein breed. In the period following implementation of genomic selection, dramatic reductions were seen in GI, especially the SB and SC paths. The SB GI reduced from ∼7 y to…

• UD
  U.S. Department of Agriculture

  Award: 1245-31000-101-00
• UN
  Universidad Nacional Autónoma de México
• AR
  Agricultural Research Service

  Award: 1245-31000-101-00