[Objective estimation of the motility of deep frozen cattle sperm by videomicrography and computer image analysis]

It was examined whether computerized image analysis (system "Brunner") is suitable for the objective evaluation of the quality of deep-frozen bull sperm obtained from the routine of breeding stations. Egg yolk particles similar in size to sperm heads were classified as immotile sperm. Thus, motility was significantly underestimated with the degree of underestimation depending on the thawing solution employed. The use of two different thawing solutions, CUE and Citrat-Glucose, resulted in significantly different sperm motion characteristics immediately after thawing as well as at the end of a 2 hour incubation period at 37 degrees C. Deep-frozen semen samples from seven bulls were compared with respect to their swimming activities. The rank order of the bulls based on the values for motility and mean velocity measured two hours post-thaw corresponded with the rank order of Non-Return-Rates with respect to bulls from the same breeding station. It appears that the combination of videomicrography and computerized image analysis is well suited for the objective evaluation of frozen-thawed bull sperm if the extender is pretreated to exclude an underestimation of motility caused by egg yolk particles.