Bioscientifica Proceedings

Methods for sexing preimplantation embryos range from karyotyping to recording speed of development in vitro. The only method used routinely on a commercial scale is to biopsy embryos and amplify Y-chromosome-specific DNA using the polymerase chain reaction. This method is effective for more than 90% of embryos and is >95% accurate. Within males, spermatozoa are essentially identical phenotypically due to: (1) connection of spermatogenic cells by intercell...

The overall aim of this research was to improve fertility of cattle inseminated with sexed spermatozoa by improving sperm sorting procedures. Six field trials were conducted in which 4,264 heifers were inseminated into the uterine body with cryopreserved sexed or unsexed control spermatozoa. Pregnancy or calving rates with doses of 2 × 106 sexed spermatozoa ranged from 32 to 51%; these averaged 69% of the pregnancy rates with 20 × 106 un...