Post-thaw Characteristics of Pinzgau Bull Semen following Long-term and Short-term Storage

The aim of the study was to examine sperm viability of Pinzgau bull insemination doses following longor short-term storage. Insemination doses, provided by Slovak Biological Services Inc. (Lužianky, Slovak Republic), were slow-frozen and stored in containers with liquid nitrogen for 1 18 years. The sperm samples were divided, according to the length of storage, to the short-term ( ≤ 15 years) and long-term ( > 15 years) groups. Post-thaw sperm assessment included total motility (CASA), dead/necrotic sperm occurrence (propidium iodide) and sperm morphology examination. No significant influence of storage length on the spermatozoa characteristics of Pinzgau bulls was noted. However, high inter-male variability in the susceptibility of Pinzgau bull sperm to cryodamages was found (P ≤ 0.05). Our results suggest that bull ́ individual variability should be taken into account when semen doses are to be stored as genetic resources for a future use.