The major barrier to accomplishment of artificial insemination in ewes is the anatomy of the cervix combined with low viability and survival of frozen ram semen. Thus, the aim of the present study was to evaluate the morphology of the cervix in ewes. Eighty-one specimens were obtained from a slaughterhouse and the following characteristics were evaluated: type of external cervical os, cervical size, integrity and interdigitation of cervical rings, gross characteristics and size of the ovaries (follicles and corpus luteum), and the time spent to pass an insemination catheter through the lumen of the cervix. The most frequent was the slit type cervical opening and grade II internal ring arrangement. The time spent to pass the insemination catheter through the cervix was 6 minutes and 15 seconds, and the dye was spread throughout the cervical lumen reaching the uterus in most sheep. The average values of cervical opening diameter and cervical length were 0.68cm and 4.4cm respectively. Ovarian follicular activity was found in 75% of the ewes. A positive correlation was established between some of the variables. We conclude that cervical opening size is influenced by estrogen, slit type cervical os and grade III cervical ring arrangement; also, the greater length of the cervix was associated with greater difficulty to pass the insemination catheter.
Sheep; artificial insemination; cervical morphology
