Submitted to: European Association of Animal Production Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 24, 2009
Publication Date: November 1, 2009
Citation: Norman, H.D., Hutchison, J.L. 2009. Effect of sexed-semen use on Holstein conception rate, calf sex, dystocia, and stillbirth in the United States. European Association of Animal Production Proceedings. 15:242. Technical Abstract: Most artificial-insemination organizations in the United States now market sex-sorted semen. For 10.8 million US Holstein breedings with conventional semen since January 2006 and 122,705 sexed-semen breedings, data were available from all breedings for conception rate, 12 and 9% of breedings for calf sex and dystocia (births reported as requiring considerable force or extremely difficult), and 10 and 9% for stillbirth (born or died within 48 h). Statistical differences were determined by chi-square tests. Conception rate and calf sex ratios differed (P<0.001) with use of conventional and sexed semen. Conception rate was 57% for heifers and 30% for cows with conventional semen and 43 and 25%, respectively, with sexed semen. For heifers, 50% of calves were single females; 49%, single males; and 1%, twins with conventional semen; corresponding percentages for cows were 45, 49, and 5. With sexed semen, 90% of calves were single females; 9%, single males; and 1%, twins, for heifers and 85, 11, and 5%, respectively, for cows. Significance of differences for dystocia and stillbirth incidences with use of conventional and sexed semen varied. For births from conventional semen, incidence of dystocia was 4% for single female calves, 8% for single male calves, and 8% for twin calves for heifers (P<0.001) and 2, 3, and 5%, respectively, for cows (P<0.001); corresponding incidences of dystocia with sexed semen were 4, 9, and 4% for heifers (P<0.001) and 1, 1, and 2% for cows (P>0.05). Stillbirth incidence with conventional semen was 9% for single females, 11% for single males, and 15% for twins for heifers (P<0.001) and 4, 4, and 8% for cows (P<0.001); corresponding incidences of stillbirth with sexed semen were 10, 15, and 13% for heifers (P<0.001) and 3, 4, and 8% for cows (P>0.05). Differences between conventional and sexed-semen breedings for dystocia and stillbirth incidences may have been affected by herd recording practices.