Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Theriogenology

The present study was designed to investigate centrifugation protocols, type of diluent, dilution rate, type of cryoprotectant and cooling on post thaw quality of Arabian stallion spermatozoa. Semen was collected from four adult pure Arab stallions on a regular basis (one ejaculate / week / 10 successive weeks). After collection, semen was evaluated using conventional methods. Centrifugation protocols were done on gel free fraction (no-centrifugation, 600 xg / 10,15 min.,900 xg / 10,15 min and 1200 xg / 10,15 min.). Two semen extenders were used: INRA 82 and modified Kenney{u2019}s extender at dilution rates of 1:1, 1:2 and 1:3. Glycerol 5%, dimethyl formamide (DMF) 5% and glycerol 2.5% + DMF 2.5% were used as cryoprotectants. Cooling over a period of 1 hr., 1.5 hr. and 2 hr was practice prior to freezing. The post thaw studied parameters were progressive motility, live percentage, total abnormalities, viability index and plasma and acrosomal membrane integrities. Based on results of current study centrifugation of stallion semen at 600 xg for 15 minutes before cryopreservation could overcome the damaging effect of plasma membrane indicated by significant improvements of sperm characteristics of post-thaw spermatozoa. Dilution of centrifuged stallion semen with INRA-82 extender at a rate 1:1 could be used for improvement freezability of spermatozoa

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