Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: February 24, 2011
Publication Date: June 30, 2011
Citation: Olson, K.M., Hutchison, J.L., Van Raden, P.M., Norman, H.D. 2011. Changes in the use of young bulls. Journal of Animal Science 89(E-Suppl. 1)/Journal of Dairy Science 94(E-Suppl. 1):27(abstr. M67). Technical Abstract: Availability of genomic information since 2008 has increased accuracy of genetic evaluations for young bulls in Holstein (HO), Jersey (JE), and Brown Swiss (BS). As a result, AI organizations have been aggressively promoting young bulls and producers have been using young bulls more extensively. Number of inseminations by breeding year and service sire (SSR) age at the time of insemination was investigated using US breeding records from 2007 through 2010. There were a total of 65,686 BS, 14,319,994 HO, and 771,766 JE inseminations. Age of SSR was categorized into 3 groups: young bulls (0.8–3.9 yr), first crop sires (4.0–7.9 yr), and older sires (>= 8.0 yr). There was an increased use of young bulls between 2007 and 2010 for HO and JE (Table 1); increase in inseminations by young bulls was 14 percentage units for HO and 7 percentage units for JE. This was not surprising, because HO gain more in accuracy from genomics than the other breeds. First crop sire usage decreased for HO (14 percentage units) and JE (3 percentage units). Older sire usage remained constant at 15 to 18% for HO, 16 to 23% for JE, and 33 to 36% for BS. Economic ($) rankings have been converted to percentile rankings since 1980 with the average of proven bulls being 50%, as a comparison, the 294 young HO bulls currently being marketed averaged +459 Net Merit and a 83 percentile ranking. When young bulls have reliabilities > 60%, simulations indicate that the optimum usage of young bulls may increase to > 90% of the market share. Current average genomic reliabilities for Net Merit are 73, 60, and 48 % for HO, JE, and BS, respectively. The shift to increased inseminations to young bulls is likely to continue.