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.