Animal Science, Department of


Date of this Version

January 2002


Published in 2002 Nebraska Beef Cattle Report. Copyright © 2001 The Board of Regents of the University of Nebraska.


A two-year study was conducted on 457 yearling replacement heifers to evaluate effects of sexed (female) sperm compared to normal (control) sperm on AI conception rates, fetal sex ratio and pregnancy rates of heifers. All heifers were estrous synchronized, heat detected and bred by AI. Semen from three bulls was collected and sexed by a sperm sorter located at Colorado State University. Results showed a 3% to 13% reduction in AI conception rates of heifers inseminated with low dose, sexed sperm compared to normal dose, control sperm; with overall 50-day pregnancy rates being similar. Fetal female sex ratio was 92% for sexed sperm compared to 49% for control sperm. Sperm can be successfully sexed resulting in slightly lower AI pregnancy rates, but yielding 90% of the preselected sex of calf.