X
sort rate, percent of membrane-impaired sperm, and split (degree of separation between
X- and Y-bearing sperm populations). The percent of live-oriented sperm was higher for
sperm incubated with 0% seminal plasma (64%) than for sperm incubated with 5%, 10%, or
20% seminal plasma (60%, 59%, and 58%, respectively; P < 0.05). The X sort rate was higher
for sperm incubated with 0% seminal plasma than sperm with 20% seminal plasma (4.26
vs. 3.61 103 sperm per second). When seminal plasma was exchanged between bull
ejaculates, only one bull had seminal plasma that was detrimental to sperm, resulting in
31% membrane-impaired sperm compared with a range of 16% to 19% for seminal plasmas
from other bulls (P < 0.05). The addition of BSA did not affect sort efficiency at the
concentrations studied. Sperm from six bulls stored for 8 hours without seminal plasma
had more membrane-impaired sperm (which were discarded) during sorting (28%) than
with seminal plasma (19%; P < 0.01), but higher postthaw motility postsorting (63%) than
with seminal plasma (52%; P < 0.05). In conclusion, the presence of seminal plasma during
staining and sorting decreased sort rates and percent of live-oriented sperm, and storing
sperm without seminal plasma increased postthaw motility.