DEVELOPING THE USE OF EPIDIDYMAL SEMEN FOR FARM ANIMAL CRYOBANKS AND SOME FIELD APPLICATIONS

The aim of this thesis was to increase our knowledge in the use of epididymal semen for the creation of cryobanks for farm animal genetic resources, and more generally to contribute to the area of conservation and sustainable use of farm animal genetic resources (AnGR).Three experiments were conducted in cattle and goat species. In cattle the effects of two epididymal sperm extraction methods, the float-up and the retrograde flushing technique were compared in terms of quality of epididymal sperm recovered. Results suggest that in this species retrograde flushing technique is the method of choice to obtain viable sperm from the epididymis (Turri et al., 2011. Reprod Dom Anim, doi: 10.1111/j.1439-0531.2011.01948.x, in press). In the second experiment, the relationship between body weight, secondary sexual traits and epididymal semen quality in Camosciata della Alpi bucks was evaluated. It was concluded that epididymal semen quality in goat species is influenced by body weight, scrotal circumference, horn diameter and length, and testicular and epididymal weight. In the third experiment, the effects of time elapsed between animal’s death and sperm recovery (0, 24, 48, 72 hours) from the epididymis and the effect of testicles storage temperature (environmental temperature or 5°C) on quality and freezability of epididymal buck spermatozoa were investigated. Sperm recovery was performed by using the retrograde flushing technique. It was concluded that goat epididymal spermatozoa extracted by testicles stored at 5°C until 48 hours post-mortem are able to maintain their quality in terms of total motility, viability and sperm morphologies, also after cryopreservation. A field application was carried out within the creation of the Lombardia Farm Animal Genetic Resources Cryobank (LABank), when epididymal spermatozoa of the Brianzola sheep were collected instead of conventional semen collection. At present in the LABank genetic material of Varzese cattle, Brianzola sheep and Frisa, Orobica and Verzaschese goats breeds is stored. Information of donors animals and material stored are managed through the software CryoWEB (http://cryoweb.vete_vsa.unimi.it/). A coordination system of Italian collections was also developed, through the creation of the “Network of the Italian cryobanks of farm animal genetic resources” CRIONET-IT (http://www.genrescryonet.unimi.it/). Finally, farmers’ motives and values in keeping local cattle breed were investigated trough 371 interviews of farmers of 15 local cattle breeds, in 8 European countries. The work was part of EC EURECA project (Towards self-sustainable EUropean REgional CAttle breeds) aimed to define guidelines for the management of in situ and ex situ regional conservation programmes, with reference to the cattle species (Gandini et al., 2010. Animal Genetic Resources, 47, 45–58).