Successful Endoscope-Assisted Transcervical Insemination (TCI) in Dogs Using Sperm Recovered from Epididymides Stored...

The recovery and cryopreservation of epididymal spermatozoa enable genetic preservation in male dogs that die unexpectedly or require castration; however, sperm collection is typically performed immediately after surgery, and artificial insemination is often surgical. This study aimed to evaluate whether epididymides stored at 4-5 °C for 24 h prior to sperm recovery retain fertilizing capacity after cryopreservation and whether pregnancy can be achieved using endoscopically guided transcervical intrauterine insemination. Testes and epididymides from an eight-month-old German Shepherd dog were stored in physiological saline at 4-5 °C for 24 h following castration. Spermatozoa were recovered from the cauda epididymis using single-incision aspiration, evaluated, frozen according to the Uppsala method, and stored in liquid nitrogen for two months. After thawing, 62 × 10⁶ progressive motile spermatozoa were inseminated once into a bitch in heat using transcervical endoscopic guidance. Pregnancy was confirmed by ultrasonography, and nine healthy puppies were delivered at term. These findings demonstrate that 24 h refrigerated storage of the epididymis does not impair post-thaw fertilizing ability and that non-surgical transcervical intrauterine insemination represents an effective alternative to surgical techniques for the use of frozen-thawed epididymal semen in dogs.