Danish A.I. field data with sexed semen

Abstract: The objective of this study was to compare conception rates, non-return rates and sex ratios of sexed and conventional semen from the same sires in commercial dairy herds in Denmark. The semen was produced from three bulls from each of the three major dairy breeds in Denmark: Holstein, Jersey and Danish Red Dairy Breed (nine bulls total), in order to answer questions on breeds differences in field results. AI was performed by trained technicians using a minimum of 150 doses of sorted sperm and 50 control doses from each bull. During the trial, a total of 2087 doses were used in 63 herds. The trial showed that the conception rate using sorted semen was 5% points lower than with conventional doses for Danish Reds, 7% points for Jerseys, and 12% points for Holsteins. Translating this into non-return rate revealed differences of 10–20% points among bulls. These differences are thought to be a good indicator of what to expect from commercial use of sexed semen. The sex ratios varied from 89% to 93% female calves among breeds, which on average is consistent with the theoretical average sex ratio of 93% females considering the low number of inseminations. [Copyright &y& Elsevier]