Use of DMSO for the cryopreservation of Tritrichomonas foetus in liquid nitrogen.

Four Tritrichomonas foetus strains were successfully preserved in liquid nitrogen at -196 degrees C in the presence of 10% dimethylsulfoxide (DMSO) for 7 months (Strain 1) and 6 months (Strain 2, 3 and 4). The percentage of viable organisms after thawing ranged between 65 and 85%, depending upon the strain. The method used is described in detail.