Table 5.

Morphological defects observed in studies after heat stress due to scrotal isolation in cattle.

Heat stroke period	Days on which sperm morphological abnormalities are evidenced in semen after heatstroke	Observed morphological defects	References
48 h	6–23 days	Decapitated sperm, abnormal acrosomes, abnormal tails, and protoplasmic droplets	Wildeu and Entwhistle (149)
48 h	12–36 days	Tailless sperm, diadem defects, piriform head, nuclear vacuoles, knotty acrosomes, and drag defects	Vogler et al. (150, 151)
48 h	14–42 days	Piriform heads, large heads, nuclear vacuoles	Rahman et al. (152)
48 h	23–34 days	Piriform heads, vesicle formation in the equatorial region of the sperm head (diadem defect), apical vacuoles	Walters et al. (153)
72 h	15–49 days	Piriform heads, detached heads, midpiece defects, proximal droplets	Newton et al. (154)
96 h	18–25 days	Piriform heads, nuclear vacuoles, microcephalic sperm and abnormal DNA condensation	Barth and Bowman (155)
120 h	14–21 days	Head abnormalities, nuclear vacuoles, acrosome and midpiece defects	Fernandes et al. (156)

Source: Adapted from Rahman et al. (95).