Comparative Study on the Effect of Three Extenders on Post-thaw Sperm Motility in Arabian Stallions

The aim of the present study was to evaluate the effect of three semen extenders on the post-thaw motility of sperm from Arabian stallions. Semen was collected from six Arabian stallions, evaluated for standard semen parameters, diluted with centrifugation extenders in a ratio of 1:1, then cushioned centrifugation 1000 xg for 10 minutes, the sperm pellet was removed using catheter coupled with a syringe and divided into three portions, the first portion was diluted with MX freezing extender, the 2nd portion was diluted with STAR freezing extender while the 3rd portion was diluted with DMF egg yolk based extender, packad in 0.5 ml straws and sealed using glass-balls in manual semen filling and sealing machine at the room temperature , straws were placed on rack, cooled slowly in the refrigerator for 25 minutes in case of DMF egg yolk based extender and for 1 hr. in case of MX and STAR freezing extender, then removed from refrigerator and was put in Styrofoam box contains 4 cm liquid nitrogen -120 ℃ for 13 minutes, evaluated for the motility then plunged in liquid nitrogen at -196 ℃. Results showed that MX and STAR freezing extenders improved the post-thawing motility of sperm but not significantly (P < 0.05) like DMF egg yolk based extender. In conclusion, Lyophilized extenders can be used for cryopreservation of stallion ̓s sperm with the advantage of storage and distribution at room temperature.