MOTILITY, VELOCITY, AND ACROSOME INTEGRITY OF EQUINE SPERMATOZOA STORED UNDER DIFFERENT CONDITIONS

Ejaculates from 58 3-year-old stallions was used for sperm motility an d velocity evaluation. The ejaculate from each stallion was divided in to two halves which were diluted in either egg-yolk extender (D11) or skim-milk extender (SME). One half of each sample was stored at room t emperature and the other half at 5-degrees-C. Sperm motility and veloc ity in each sample was assessed at 0 h and after 6, 18 and 42 h storag e. Mean sperm motility and mean sperm velocity were best preserved whe n semen was kept at 5-degrees-C in SME. Acrosome integrity was evaluat ed in fresh diluted semen and after 18 and 42 h of storage in either D 11 or SME by indirect immunofluorescent-staining technique using a mon oclonal antibody. In both extenders, the frequency of damaged acrosome s increased with time of storage, although, in the freshly diluted sem en, there was a significantly higher frequency of damaged acrosomes in the D11 than in the SME extender.