SOJ Veterinary SciencesOpen Access Research Article modifications have been proposed for the freezing process [6]. It has been estimated that only 30-40% of stallions produce semen suitable for cryopreservation [7]. Moreover, consistent variation of sperm freezability has been observed from breed to breed [8,9]. At present, there is no standard protocol for stallion semen cryopreservation able to achieve consistent and acceptable post thaw sperm fertilizing capacity with every ejaculate [10]. That lack of standard can be attributed to many factors, including damage to the sperm membrane that may occur during the process of freezing or thawing [11]. In addition, the cryopreservation extender has an important influence on post thaw sperm quality [11].Many diluents have been used in different animal species, with good results in post thaw sperm motility, but they have not been used with the semen of Arabian horses. Several diluents have been used in stallion semen, with good results such as Kenney's diluent, cream-gel, skim milk diluent, glycine egg yolk, sugar-based extender and INRA 96 extender [12,13]. The use of Computer-Assisted Semen Analysis (CASA), which facilitates objective measurement of several parameters of sperm motility, offers a more reliable and repeatable means of assessing sperm motility than does examination by eye [14]. The CASA system is therefore able to determine a series of variables, including number of moving spermatozoa, Curvilinear Velocity (VCL), Linear Velocity (VSL), Linear Coefficient (LIN), straightness coefficient (STR) and frequency of head displacement (BCF) [15].Success with frozen semen requires attention to detail and a basic understanding of the techniques involved in the proper handling, thawing, and insemination of frozen semen [7]. Frozen stallion semen is now used more extensively by minimizing freeze thaw damage to spermatozoa, and indeed, more stallions might be used and pregnancy rates might be increased. Many steps constitute interactive participation in the success of the cryopreservation process, including semen collection, dilution, cooling, freezing, and thawing [12].
AbstractForty-eight ejaculates were obtained from four Arabian stallions to study the impact of three extenders (INRA Freeze, TRIS-egg yolk and E-Z Mixin) on the fertilizing capacity of cryopreserved stallions' semen. Ejaculates were cryopreserved in 0.5-ml plastic straws with a dilution rate of 1:1 and 1:2. Frozen straws were thawed at either 37°C for 30 sec or 70°C for 7sec and used for AI of eighty Arabian mares via different protocols. Results revealed that percentages of motility; live sperm; and abnormalities were significantly (P < 0.01) better in the E-Z Mixin at 5°C with dilution rates 1:1 and 1:2. Motility characteristics such as path velocity (VAP, μm/s), straightline velocity (VSL,μm/s), Point-to-Point Velocity (VCL, μm/s) and lateral head displacement (ALH, μm) were significantly (P < 0.01) the best by using E-Z Mixin at rates of dilution 1:1 and 1:2. Conception rate was significantly (...