Diadem/crater defect in spermatozoa of a Brahman bull: seminal traits, microscopic findings and IVF fertility. Genetic predisposition?

Abstract

[Extract] With no conclusive studies, a number of factors—mostly including thermal stress—have been suggested as the etiology for the sperm defect known as diadem/crater (Larsen nd Chenoweth, 1990; Vogler et al., 1993). A 1-year study conducted on 16 Bos taurus and Bos indicus bulls showed a consistently high percentage (up to 95.5%) of spermatozoa bearing a "diadem/crater" (D/C) defect in the semen of a 6-year-old Grey Brahman bull during the hotter months at an artificial insemination center in western Venezuela, an area representing the dry tropics. This sperm pattern reverted to essential normality during the cooler periods