In this study, the role of sperm motility and acrosome integrity in fi
ltration of bovine semen was investigated. In Experiment 1, the treatm
ent of semen with formaldehyde, hyperosmotic buffer, heating and direc
t freezing immunobilized the spermatozoa completely but their acrosoma
l status varied significantly (P<0.01). The immotile spermatozoa, of a
ny kind, did not pass through the Sephadex ion-exchange column at room
temperature. In Experiment 2, semen samples possessing different perc
entages of immobilized spermatozoa (0, 50, 75 and 100%) were filtered
through the Sephadex ion-exchange column. The immotile/dead spermatozo
a were removed proportionately to their number in the semen by Sephade
x ion-exchange column. The type and number of immotile spermatozoa in
semen had no effect (P>0.05) on the postfiltration recovery rate of mo
tile spermatozoa. Filtered spermatozoa exhibited higher (P<0.01) motil
ity (>90%), progressive motility (>70%) and normal acrosomes (>95%) th
an nonfiltered spermatozoa. In conclusion, sperm motility seems to be
more important than acrosome integrity for semen filtration, and the S
ephadex ion-exchange column can remove the known quantities of differe
nt kinds dead/immotile spermatozoa.