Is It Possible to Access the Uterus of Sheep by Endoscopy: Studies of Vaginoscopy and Hysteroscopy with Transcervical Uterine Access in Sheep

Given the endoscopic possibilities and the need to improve AI in sheep, the aim of this study was to develop a transcervical endoscopic technique for accessing the uterus in sheep. The study was conducted on 35 ewes divided according to the uterus accessing technique applied for artificial insemination (AI). In a pilot study, two techniques were tested using a rigid endoscope coupled to a protective sheath totaling 3 mm, in a group of ewes not subjected to fixed-time artificial insemination (FTAI) protocol and those subjected to the protocol (EPG, <i>n</i> = 5 and EPGp, <i>n</i> = 10). After the pilot study, two additional techniques were tested in synchronized ewes for FTAI: a control group with cervical traction (CG, <i>n</i> = 10) and an AI group using vaginoscopy with a multiport for the passage of a rigid endoscope (EVG, <i>n</i> = 10). The EPG and EPGp showed 100% (5/5) and 10% (1/10) cervical passage rates, respectively. The EPGp had 90% (9/10) superficial cervical inseminations, 10% (1/10) intrauterine inseminations, and a 10% (1/10) pregnancy rate. In CG and EVG, 3.5 ± 3.3 and 1.6 ± 1.2 cervical rings were passed, respectively. Additionally, semen deposition resulted in 20% (2/10) intrauterine inseminations and 80% (8/10) deep cervical inseminations for CG, while EVG had 20% (2/10) intrauterine inseminations and 80% (8/10) superficial cervical inseminations. The pregnancy rate was 20% (2/10) for both CG and EVG. The EPG technique proved efficient for hysteroscopy; however, EPGp was not efficient for AI due to the presence of typical estrus mucus. Nevertheless, it laid the foundation for the development of EVG, which showed promise in gynecological evaluations, enabling intrauterine AI and a complete gynecological assessment.