FILTRATION OF BOVINE SEMEN .1. DEVELOPMENT OF A SEPHADEX ION-EXCHANGEFILTER

Semen from four Holstein bulls was diluted in TEST-yolk buffer (1:5 to 1:10) and then percolated through Sephadex ion-exchange filters at a rate of 1.5 ml min-1 using positive and negative pressures. Filters co ntained a fixed quantity of Sephadex (0.6 g), with a varied quantity o f ion-exchanger, i.e. diethylaminoethane (DEAE) and carboxy-methyl (CM ) celluloses (0, 0.125, 0.25 or 0.50 g). A filter containing only Seph adex gel was used as a control. Post-filtration quality of semen sampl es was ameliorated by all types of filter. The addition of ion-exchang ers on a Sephadex column improved all the characteristics of spermatoz oa involving motility and viability (P<0.01), regardless of their quan tity in the column (P>0.05). Post-filtration recovery rates of spermat ozoa varied with different filters (P<0.01) and was highest with the c ontrol filter (82.5%). Motility (P<0.02) and progressive motility (P<0 .02) were better in the filtrates obtained with negative pressure. A c olumn composed of 0.6 g of Sephadex and 0.5 g of ion-exchangers with n egative pressure was selected for use in further experiments. A Sephad ex ion-exchange filter is effective in improving the quality of bovine semen.