Assessment of sperm viability by measurement of ATP, membrane integrity and motility in frozen/thawed bull semen.

Control of sperm quality after commercial freezing/thawing of bull semen is still restricted to the subjective assessment of sperm motility, despite its low correlation to fertility ( 1991, 1993). Although no single in vitro method has yet been designed to predict the fertilizing ability of a given semen sample, the quantitation of viable spermatozoa (with intact plasma and acrosome membranes, and metabolically active) seems to be most promising ( 1991). The present report describes the use of a bioluminiscence technique to determine ATP-levels and a novel supravital stain (using fluorescent dyes) to assess the amount of viable spermatozoa in frozen/thawed semen from 3 A.I. dairy bulls with significantly different motility after thawing.