Abstract
Until now it has been unclear to what extent the reduced fertility with sexed semen in the dairy industry is caused by too few sperm per AI dose, or by the effect of flow cytometric sorting, which is the established procedure for sexing semen. Therefore, we evaluated the effects of low sperm numbers per dose with and without sorting on non-return rates after 56 days (NRR56); in addition, we evaluated the effects of bulls, in order to further optimize use of sexed semen. Based on results of using sexed semen from seven Holstein bulls, an overall numerical decline of 13.6% in NRR56 was observed ( P < 0.05). About two-thirds of this decline (8.6%) was due to the low dose ( P < 0.05), and a third (5.0%) due to the process of sorting ( P < 0.05). The effect of low dosage and sorting differed among bulls. We observed a sex ratio of 91.6% females for sexed semen from the first 131 calves born. Currently the best way to increase fertility of sexed semen is by closely monitoring fertility so that the highest fertility bulls are used, and by improving farm animal management. However, to make substantial progress, more in depth studies are needed on the sexing technology, especially on aspects such as sorting procedures and sperm dosage.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
