1. Early embryo development takes place in the donor cow. | 1. Early embryo development takes place in an incubator with artificial media. |
2. Fertilization is done by artificial insemination of the donor. | 2. Fertilization is done in the laboratory. |
3. Three to six semen straws are used to inseminate one donor. | 3. One semen straw can be used to fertilize oocytes of up to 8 donors. |
4. The embryos exposure to external factors are lower, thus less risk. | 4. Greater risk due to more handling of embryo and exposure to external factors. |
5. Embryos are flushed from the donor cow | 5. Oocytes (egg cells) are aspirated from the donor. |
6. The donor is stimulated with hormones for superovulation | 6. No hormones are required. |