INTERRELATIONSHIPS AMONG FLUOROMETRIC ANALYSES OF SPERMATOZOAL FUNCTION, CLASSICAL SEMEN QUALITY PARAMETERS AND THE FERTILITY OF FROZEN-THAWED BOVINE SPERMATOZOA
Sa. Ericsson et al., INTERRELATIONSHIPS AMONG FLUOROMETRIC ANALYSES OF SPERMATOZOAL FUNCTION, CLASSICAL SEMEN QUALITY PARAMETERS AND THE FERTILITY OF FROZEN-THAWED BOVINE SPERMATOZOA, Theriogenology, 39(5), 1993, pp. 1009-1024
Cryopreserved spermatozoa from 8 bulls were used to examine the interr
elationships among flow cytometric spermatozoal quality assessments an
d classical semen quality parameters and nonreturn rate estimates of f
ertility. The integrity of the sperm cell membrane and the functional
capacity of the mitochondria were quantified by flow cytometry after c
oncurrent staining with carboxydimethylfluorescein diacetate (CDMFDA),
propidium iodide (PI), and rhodamine 123 (R123). For each sample a to
tal of 10,000 stained spermatozoa were simultaneously quantified for t
he intensity of their green and red fluorescence. Three straws from ea
ch bull were each examined initially and following incubation at 37-de
grees-C for 3 hours to assess the rate of senescence. The proportion o
f spermatozoa retaining membrane integrity and having functional mitoc
hondria, as determined by CDMFDA and R123 staining, were compared with
classical semen quality assessments (sperm motility, acrosomal status
, cellular and head morphology, presence of vacuoles/craters and cytop
lasmic droplets) and with fertility (nonreturn to estrus rates). For i
ndividual ejaculates nonreturn rates, the range was from 61.8 to 78.8%
, whereas the cumulative rates of several ejaculates for each bull ran
ged from 71.3 to 83.5%. The proportion of spermatozoa with functional
membranes and mitochondria were positively correlated with the percent
age of spermatozoa with normal morphology (r=0.82; P=0.01) and motilit
y after 4 hours of incubation (r=0.78; P=0.02), but not with the estim
ates of fertility. The actual number of spermatozoa per straw staining
with CDMFDA and R123 after 4 hours of incubation at 37-degrees-C was
correlated with the percentage of spermatozoa with normal morphology (
r=0.73; P=0.04). Multiple regression equations indicated that combinat
ions of semen quality measurements could be useful in estimating ferti
lizing potential.