Veterinary Andrology and Reproductive Techniques

VAS DEFERENS / DUCTUS DEFERENS

• It extends from cauda epididymis to the colliculus seminalis of the pelvic urethra.
• The ducts are firm having two thick involuntary muscular layers (longitudinal and circular) and lumen quite small.
• The ducts are convoluted near the cauda epididymis and then run parallel to the corpus epididymis and then through the inguinal canal into the abdominal cavity along with other components of the spermatic cord.
• After reaching the abdominal cavity, the vas deferens separates from the spermatic cord, passes upward and backward to open into the pelvic urethra.
• The vas deferens is about 3 mm thick in bull and about 6 mm thick in stallion.
• The fusiform distal enlarged part of the vas deferens is called ampulla. Here the storage of the sperm occurs.
• The ampulla is furnished with branched tubular glands.
• The ampulla in bulls measures about 10 to 12 cm in length and 1.0 to 1.5 cm in diameter.
• There is no ampullae in dog and cat and it is small in boar.
• The ampullae open in the cranial portion of the pelvic urethra through a rounded prominence called “colliculus seminalis”.
• In the vas deferens the sperm transport is due to peristaltic waves.
• Blood supply – Spermatic artery and internal pudic artery
• Nerve supply – Pelvic plexus

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