J. Dairy Sci. 88:776–782 American Dairy Science Association, 2005. In Vitro Production of Holstein Embryos Using Sex-Sorted Sperm and Oocytes from Selected Cull Cows

The objective of this study was to explore potential synergies between sex-sorted sperm and in vitro em-bryo production for generating replacement heifers on commercial dairy farms. Selected involuntary cull cows (i.e., genetically suitable cows that were culled due to injury, illness, or infertility) from 7 Wisconsin farms were used as donors, and ovaries were collected via colpotomy or at the time of slaughter. Oocytes were aspirated, fertilized in vitro with sex-sorted sperm 22 ± 0.2 h later, cultured, matured for 7 to 8 d, and trans-ferred into recipient cows and heifers on the farms from which the cull cows originated. From August 2002 to June 2003, ovaries were recovered from 104 Holstein donors. Sex-sorted sperm from 3 Holstein sires (ob