DNA status on thawed semen from fighting bull: a comparison between the SCD and the SCSA tests

The assessment of sperm chromatin status is compulsory in a complete spermiogram. Here we applied the Sperm Chromatin Structure Assay (SCSA) and the Sperm Chromatin Dispersion test (SCD) to assess the chromatin status of three fighting bulls. Cryopreserved semen (two straws/bull) were analyzed by duplicate after thawing and after 6 h at 37 C with and without oxidative stress (1 mM Fe2+). Results (SCD: % of spermatozoa with halo; SCSA: SD-DFI, %DFI and HDS) were analyzed for differences between bulls and treatments, sensitivity and specificity (Receiver Operating Characteristics curves; ROC) and repeatability (repeatability coefficients as 2SD of duplicate differences). %DFI for the three bulls was below 2% at 0 h, indicating no risk for fertility according to previous reports. It increased slightly for two of the bulls after Fe2+ treatment (%DFI