An experiment was conducted to study the freezability of unwashed and washed buffalo spermatozoa in egg yolk tris (EYT) dilutor modified by addition of 0, 3, 6 and 10% fetal calf serum (EYT-So, EYT-S1, EYT-S2 and EYT-S3, respectively). Acrosome reaction test, in addition to sperm motility, livability and total sperm abnormalities, was performed at 0 hr (after dilution), PF (pre-freezing/after equilibration) and PT (post thaw) stages to evaluate the dilutors for maximum recovery of post-thaw fertilizing ability, motility and livability. Washing significantly (P < 0.01) affected acrosome reaction percentage, sperm motility, livability and total abnormalities. Dilutors were non-significant on all parameters, whereas acrosome reacting spermatozoa were higher in EYT-S3 dilutor for unwahed and in EYT-S2 dilutor for washed samples. PT motility and livability were higher in EYT-S2 dilutor as compared to control for both unwashed and washed samples. Total sperm abnormalities were within normallirnits in all dilutors at all stages.
