Testing of Bull Semen 

Published April 3, 2023

Because bulls with atypical sperm produce fewer successful fertilizations and therefore fewer calves, veterinarians test semen to gauge a bull's eligibility to breed. 

Bulls with more than 30% abnormal sperm cells (i.e. cells with detached acrosomes or reduced mobilities) are excluded from breeding.

This week I assisted in the semen testing of a Holstein Friesian bull: An electric probe was administered rectally to stimulate ejaculation and the resulting semen was examined under a microscope. This particular bull was cleared to breed because 71% of its sperm cells were normal.