Comet assay of fresh and cryopreserved bull spermatozoa

In this study, we describe DNA fragmentation of fresh and cryopreserved bull spermatozoa using the comet assay. Cryopreservation caused a significant but low (3.8%) decrease in the percentage of DNA in the comet head and an increase (5.3%) in the tail length. Our results suggest that in addition to motility and viability, low levels of DNA fragmentation after cryopreservation is a characteristic of bull spermatozoa and can be a part of remarkable cryoresistance of bull spermatozoa. (c) 2007 Elsevier Inc. All rights reserved.