[Size of pellets and individual properties of boar semen in relation to the number of motile spermatozoa following defrosting].

The second fraction of the ejaculate of five boars of the Landrace breed was used for the experiments. Non-diluted semen was kept in hydrogen atmosphere for three hours at + 5 degrees C; then it was frozen in solid carbon dioxide into 0.1 ml, 2.0 ml, and 5.0 ml pellets and in liquid nitrogen vapours into the shape of disk or cylinder 5 ml in volume. The pellets were de-frozen on a teflon pan at 42 degrees C without addition of any other diluent. Ejaculate in which at least 25% of the spermatozoa were motile was considered to be usable. No statistically significant difference was found between the motility of spermatozoa frozen in the 0.1 ml and 2.0 ml pellets, but it can be said that on an average the motility of the spermatozoa was lower in larger pellets; this could be observed mainly in the pellets with the volume of 5.0 ml. Large differences were revealed in the freezability of the semen of different boars, irrespective of the size of the frozen pellet. Insemination of 38 gilts with semen from 2.0 ml pellets gave a 57,8 % concentration rate (22 gilts) and the average litter size was 8.25 piglets.