ABSTRACT
Semen from10 fertile 1/2 Damascus-1/2 Baladi crossbred bucks (3-5 years old)
was collected by artificial vagina twice weekly for 12 months. Eُjaculates with mass
motility ≥80% were pooled to be used in series of five experiments. In the 1st
experiment, semen was diluted with Tris-citric acid-glucose-glycerol extender to select
the best level of egg yolk among the levels 2.5, 5.0, 7.5, 10.0, 15.0 and 20% verifying
the highest sperm post-thawing motility where it was found as 2.5%. Experiment II,
was to select the best dilution rate among the rates 1:4, 1:5, 1:8, 1:10 and 1:16 which
was found to be 1:5. Semen diluted with 2.5% egg yolk in Tris-based extender at a rate
of 1:5 was used to compare freezing in straws or in pellets form (Exp. III). In
experiment IV, post-thaw sperm motility and recovery rate were compared among
months of the year. Fertility rate by using frozen semen in pellets form with different
sperm cell doses (100, 200 and 300x106/cervical inseminate) was assessed (Exp. V).
The results revealed that sperm motility percentage was the highest in postthaw
semen diluted with Tris extender containing 2.5% egg yolk at a rate of 1: 5
(54.5%, P<0.05) and the lowest (45.4%, P<0.05) at a rate of 1:16. Freezing goat semen
showed higher post-thaw motility when was in pellets compared to straws (49.04% vs.
43.54%, P<0.05). Sperm motility in fresh, post-diluted and post-thaw semen showed
the highest values during autumn months (Sept.-Nov.) and the lowest during summer months (June-Aug.). Fertility rate in does artificially inseminated with 100, 200 and 300
x 106 motile spermatozoa in pellets form was 31.57, 42.10 and 50.00%, respectively.