MVSc

The objective of the study was to find out the effect of
different freezing rates on post thaw motility, livability and
acrosomal damage of dog spermatozoa. A total of 36 ejaculates of
good quality collected from SIX Dachshund dogs by digital
manipulation were processed for freezing in Tris citric acid
fructose egg yolk diluent containing four per cent glycerol. The
processed semen samples were subjected to three different freezing
protocols such as 4cm height above the liquid nitrogen level for 10
minutes (Fast freezing), Scm for 15 minutes (Moderate freezing)
and 12cm for 20 minutes (Slow freezing).
The mean volume of sperm rich fractions was
0.6S±0.03ml. The colour and consistency of sperm rich fractions
were thin milky. The mean density of sperm rich fraction was
DD(D) and mean pH was 6.63±O.02. The mean concentration of
sperm rich fraction was 221±7.36 millions per ml and the average
initial motility was found to be 75±O.93 per cent. The mean
percentage of live sperm count, sperm abnormalities and acrosomal
damage of spermatozoa was Sl.17±O.73, 5.23±O.29 and 2.32±O.25

respectively. Significant (P abnormalities and acrosomal damage of spermatozoa was found
between dogs.
The average percentage of motility, live sperm count,
sperm abnormalities and acrosomal damage of spermatozoa was
70.41± 1.22, 75.63±O.65, 7.28±0.43 and 5.34±O.31 after dilution,
58.75±1.34, 63.60±O.89, 10.04±O.32 and 10.13±0.41 after chilling
and 47.78±1.59, 50.65±1.31, 11.79±O.36 and 16.20±O.57 after
equilibration period respectively. There was significant (P reduction in sperm motility and livability and increase in sperm
abnormalities and acrosomal damage of spermatozoa after dilution,
chilling and equilibration period. Significant (P was found between dogs for the above parameters.
The percentage of post thaw motility of spermatozoa
was significantly (P when compared to moderate (25.83±1.66) and slow (24.44±1.27)
freezing rates. There was significantly (P of live sperms and lower percentage of sperm abnormalities in fast
freezing rate than in moderate and slow freezing rates. Eventhough
the percentage of acrosomal damage was not statistically


(

significant among fast, moderate and slow freezing rates, lower
percentage of acrosomal damage was recorded in fast freezing rate.
From this study it could be inferred that fast freezing
in which the straws were frozen at to 4cm height above the liquid
nitrogen level for 10 minutes was superior to moderate (8cm for 15
minutes) and slow (12 cm for 20 minutes) freezing rates.