Submitted to: Hoard's Dairyman
Publication Type: Popular Publication
Publication Acceptance Date: 2/5/2007
Publication Date: 5/10/2007
Citation: Norman, H.D., Wright, J.R. 2007. Genetics can improve fertility by 15 percent. Hoard's Dairyman. 152(9):350. Interpretive Summary:
Technical Abstract: Good herd reproductive management practices are important but genetics can also help improve herd fertility. USDA’s Animal Improvement Programs Laboratory began genetic evaluations for fertility in 2003 using the trait daughter pregnancy rate (DPR). DPR is defined as the percentage of non-pregnant cows between 50 and 250 days in milk that will become pregnant in the following 21 days. There are artificial insemination bulls being marketed that can help improve herd fertility. Using the highest DPR bulls can reduce days open and help reverse the genetic decline in fertility. There are two Holstein bulls currently marketed that are +3.2 for DPR. These bulls are expected to reduce days open by almost 13 days in the average herd through earlier conception. Days open has increased 37 days in 40 years. Of that, 17 days are associated with genetics from increased milk yield, and the remaining 20 days are attributed to changes in the management practices. By using the best DPR bulls, much of the genetic decline in fertility from using high-producing bulls for the last 40 years could be recovered in one generation. In spite of this potential for improving fertility, it is still our recommendation that most producers should be selecting bulls primarily for overall merit using one of the 3 Lifetime Net Merit indexes, and varying secondary emphasis on DPR, depending on the specific fertility needs of their herd.