Data from 13,982 embryo transfers, performed on dairy farms during a 5-year period (2008–2012), collected from the Finnish national database (Agricultural Data Processing Center Ltd., Vantaa, Finland), were analyzed. All embryos were derived from superovulated donors. Data on embryo transfers with ambiguous or inadequate information were eliminated from the original data set. The criteria for pregnancy were as follows: the animal did not undergo artificial insemination or have a new embryo transfer after the original embryo transfer and had registered calving data for fewer than 290 days after the transfer. This information was used when calculating the pregnancy rate, i.e., number of animals pregnant divided by the number of transfers. Consequently, 988 transfers were excluded because there were no data on calving and no service after the embryo transfer. Also, 203 transfers were removed because of conflicting calving date and transfer date. Additionally, data for animals with an aberrant history were removed. These comprised animals reinseminated 2 to 8 days after the transfer (n = 9), animals that had been inseminated more than four times before the embryo transfer (n = 324), and animals with an exceptionally short time period (<43 days) from calving to the embryo transfer (n = 20). The remaining data were for transfer of 12,438 embryos, both fresh and frozen thawed, of which 10,697 were produced with conventional semen (CONV embryos) and 1741 with sex-sorted semen of 97 bulls (SEX embryos).Calf mortality was analyzed in addition to the pregnancy rate. Data for calf mortality were collected from the same database as the data for embryo transfers, and they comprised abortions at a stage of 180 or more days of gestation and neonatal death of calves less than 7 days of age.
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