Abstract:
The aim of this study was to investigate the time-dependent changes in
motility and longevity of stallion spermatozoa diluted in different spermatozoal
concentrations and extenders during cool-storage at 5 oC. Ten purebred
Arabian stallions, ranging from 10-24 years of age, were used. Three semen
samples were collected from each stallion by artificial vagina. Each ejaculate
of 10 stallions was diluted in 3 spermatozoal concentrations (25, 50, and
75x106 in 1 ml of extender) in 3 different extenders (milk-, TRIS-based, and
glucose-lactose). Sperm motility was determined at 0, 2, 4, 24, 48, 72, 96 and
120th h after the semen was diluted. All ejaculates of each Arabian stallion
had a mean initial motility
≥ 80%. When it was compared the time-dependent
effects of different spermatozoal concentrations in the same extender; the diluted
semen with low (25x106) spermatozoal concentration had greater motility
and longevity than medium (50x106) and high (75x106) spermatozoal
concentration for each extender at all times during examination period. Similarly,
when it was compared the time-dependent effects of different extenders
in the same spermatozoal concentration; spermatozoa diluted with milkbased
extender had higher motility and longevity than TRIS-based and glucose-
lactose extenders for each spermatozoal concentration at all times. In
conclusion, the stallion semen must be mixed with an appropriate extender
that helps to the protection of spermatozoa, and spermatozoal concentration
in the extender should be low level in order to gain maximum benefit from
cooled stallion semen. Among the tested extenders the milk based extender
preserved motility for a longer time.
