Łukaszewicz E, Kruszyński W. Evaluation of fresh and frozen-thawed semen of individual ganders by assessment of spermatozoa motility and morphology. Theriogenology. 2003;59:1627-40 pubmed
..In relation to the fresh semen average from 57.2 to 63.2% of spermatozoa survived freezing process and from 23.9 to 38.5% remained morphologically intact. ..