Sperm DNA fragmentation levels (tDFI) at three incubation times for the non-heat stress (NHS) and heat stress (HS) semen collection periods.

Data are mean ± standard errors. tDFI = total DNA fragmentation index (percentage of spermatozoa with a DNA Fragmentation Index (DFI) value over 25%.) NHS = non-heat stress period (semen collections from March to May) HS = heat stress period (semen collections from June to October) a–b: different superscript letters within column indicate significant differences between semen collection periods [21]. Sperm DNA fragmentation levels (tDFI) at three incubation times for the non-heat stress (NHS) and heat stress (HS) semen collection periods.