Sperm DNA integrity in Landrace and Duroc boar semen and its relationship to litter size.

The sperm chromatin structure assay is a method for assessment of sperm DNA fragmentation, a parameter reported to be negatively related to field fertility in several mammal species. This method calculates a DNA fragmentation index (DFI) whose high values indicate abnormal chromatin structure. In this study, running from March 2010 until June 2017, the aim was to assess sperm DFI in stored liquid extended semen from two different pig breeds, Norwegian Landrace (NL; n = 693) and Norwegian Duroc (ND; n = 655), and to evaluate the influence on total number of piglets born (TNB).