studying the anatomy of the sheep cervix and its influence on the transcervical passage of an inseminating pipette into the cervix

specific structure of ewe's cervix is one of artificial insemination limitation in sheep. successful insemination in ewes has a close relation with morphology of their cervix. the objective of this experiment was to compare anatomical structure of cervix in makui, kurdish and afshari ewes. in this study, reproductive tract of 300 ewes of aforesaid sheep (100 ewes of each strain) were collected during breeding season in slaughterhouses of alborz and tehran provinces. exterior shape, opening, length and diameter of cervix, measure of penetration, kinds and number of rings were studied. the most frequent exterior shape and length were the shape of papilla and the length of 3 to 4 centimeter respectively. the dominant shape of opening in cervix in kordi and afshari ewes was papilla where as in makui ewes, the dominant shape was flop. the results showed that average cervix diameter in collected respectively was 9.34±1.7. the average number of rings for all sheep between these strains was 5.59±0.8. the most frequent layout and arrangement of rings in cervical canal was the second type. the correlation between the length of cervix and number of rings, and the length and diameter of cervix were 0.24 and 0.25, respectively. there was not a significant correlation between length of cervix with ring’s angle, opening shape and age. length of cervix, diameter and number of rings were not significantly different among 3 breeds. average penetration of insemination gun into cervical canal for all data was 3.92±2.5 mm and were approximately 4.24± 2.2 3.46±1.1, 3.84±2.5 in makui, kordi and afshari ewes, respectively. the measurement of gun’s penetration into cervix is affected by cervix diameter. estrus cycle had a significant effect on measurement of penetration, while depth of penetration was lower during luteal phase and higher in non- luteal phase. also the measurement of penetration was affected by number of rings, while cervixes with more number of rings resulted in less measurement of penetration. evaluated parameters did not show any differences among breeds except the exterior shape of cervix opening.