EFFECTS OF SEMINAL PLASMA AND 3 EXTENDERS ON CANINE SEMEN STORED AT 4-DEGREES-C

Semen preservation and artificial insemination (Al) in the canine has become a common practice in veterinary medicine. Chilled dog semen is easy to handle, and several extenders can be used. The aim of this stu dy was to compare the effects on canine spermatozoa of seminal plasma and 3 extenders commonly used for chilled semen preservation in clinic al practice. The characteristics evaluated were sperm motility; veloci ty; plasma membrane status (assessed with a fluorescence staining tech nique and hypo-osmotic swelling test); acrosome morphology; semen pH; and semen osmolarity. These criteria were monitored daily in the ejacu lates of ii dogs. The ejaculates were divided into 4 aliquots. Each al iquot was extended in autologous seminal plasma, egg-yolk Tris, egg-yo lk milk or egg-yolk cream and preserved at 4 degrees C for 4 d. In 10 of 11 semen samples extended in autologous seminal plasma, motility ha d already decreased to 0% by Day 2, and the percentage of spermatozoa with intact membranes was lower than in the 3 extenders (P<0.05). Moti lity up to Day 4 was higher in egg-yolk Tris-stored spermatozoa (53.6% ) than in those preserved in egg-yolk milk (30.4%) and egg-yolk cream (14.1%). Spermatozoa stored in egg-yolk Tris also had the highest sper m velocity, whereas no difference was found in plasma membrane or acro some status (P>0.05). Egg-yolk Tris extender seems to be superior to t he other extenders tested, to preserve dog semen at 4 degrees C, altho ugh differences were not significant for all the parameters.