FILTRATION OF BOVINE SEMEN .2. FACTORS AFFECTING THE RECOVERY RATE OFSPERMATOZOA

Filter and semen related factors were studied to improve the post-filt ration recovery rate of bovine spermatozoa using a Sephadex (0.6 g) io n-exchange (diethylaminoethane (DEAE) and carboxy-methyl (CM) cellulos es, 0.25 g each) column. Mixing together the components of the column did not improve the recovery rate of spermatozoa compared with layerin g (P>0.05). A second post-filtration washing of the column with clean buffer improved the recovery rate by 8-9%, but the quality of spermato zoa was lower than after a first wash (P<0.01). Higher rates of filtra tion did not increase the number of spermatozoa recovered in the filtr ates (P>0.05). The recovery rates of spermatozoa were 2.4%, 68.3% and 70.5% at 4-degrees-C, 22-degrees-C and 37-degrees-C (P<0.01) respectiv ely. The quality of filtrate was significantly less at 37-degrees-C th an at 22-degrees-C in terms of visual motility (P<0.025), progressive motility (P<0.0005), progressive velocity (P<0.025), linear index (P<0 .0005), and percentages of live cells (P<0.0005) and normal acrosomes (P<0.025). Motility of spermatozoa seemed to be essential for successf ul filtration. An inverse relationship was found between the recovery rate and the quality of the semen or spermatozoa. It was concluded tha t a single wash of the column with extended semen at 22-degrees-C with a flow rate of 1.5 ml min-1 yielded the best semen quality with an op timum recovery rate of spermatozoa.