Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/5/2009
Publication Date: 7/12/2009
Citation: Norman, H.D., Hutchison, J.L. 2009. Effect of sexed semen on conception rate for Holsteins in the United States. Journal of Dairy Science. 92(E-Suppl. 1):208-209(abstr. T36).
Technical Abstract: Effect of sexed-semen breedings on conception rate was investigated using US Holstein field data from January 2006 through October 2008. Sexed-semen breeding status was determined by a National Association of Animal Breeders’ 500-series marketing code or by individual breeding information in a cow or heifer reproduction record from a dairy records processing center. Marketing-code 514 was not identified as sexed semen because that technology is a gender-bias semen that results in only 10% more female births than semen that has not been sex sorted. Sexed-semen breedings resulted in 91% female offspring. Only breedings with confirmed outcomes were included: 1,190,587 heifer breedings (of which 119,920 were sexed-semen breedings) and 9,835,105 cow breedings (of which 106,393 were sexed-semen breeding). Overall mean conception rates for sexed-semen breedings was 44% for heifers (compared with 57% for conventional semen) and 26% for cows (compared with 30% for conventional semen). For heifers, 80% of sexed-semen breedings were first breedings; 16%, second breedings; and 3%, third breedings, with conception rates of 45, 39, and 35%, respectively. For cows, 43% of sexed-semen breedings were during first lactation and 28% during second. For first-lactation cows, 51% of sexed-semen breedings were first breedings; 23%, second breedings; and 12%, third breedings, with conception rates of 29, 27, and 25%, respectively. For second-lactation cows, 47% of sexed-semen breedings were first breedings; 25%, second breedings; and 13%, third breedings, with a mean conception rate of 26% for the first 3 breedings. For bulls with >300 breedings, correlations between sire conception rates from sexed and conventional semen were 0.19 for heifer breedings (67 bulls) and 0.49 for cow matings (51 bulls). Corresponding correlations for bulls with >800 breedings were 0.32 (31 bulls) and 0.78 (15 bulls).