The bovine cervix, uterine body and horns
Keywords: sperm, cervix, bovine
When specimens are submerged in water, anatomical features that are not normally visible, often become obvious. In this example, the appearance of the cervix is as it is usually presented on the left. It consists of three or four inter-digitating transverse folds between the cranial vagina and uterus. These folds are very firm and fibrous and must be negotiated when cattle are artificially inseminated. The image at right reveals that the cervix is far more complex than it appears to be at left.
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The reason for the complex arrangement of longitudinal cervical mucosal folds is not immediately evident. However, in cattle, goats and humans, motile spermatozoa remain in the cervix longer than in other regions of the reproductive tract. This indicates that the cervix functions as a reservoir for spermatozoa. The cervix may also act as a filtration system, allowing spermatozoa to escape from seminal plasma and debris in the ejaculate. Certainly a filtration function is tempting to suggest in the case of another mammal, the Pilot whale. The extremely intricate and complex cervix of the Pilot whale can be seen in this LORI entry.
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The image above show the relationship between the cranial extent of the cervix, the uterine body and uterine horns. It is important to bear in mind the short length of the body (far shorter than in the mare) because when one makes a horn selection during embryo collection or insemination, the instrument must be turned immediately in the appropriate direction after entering the uterus. In mares, this is is not a consideration because the bifurcation lies 15 to 20 cm cranial to the internal cervical os in horses.
In this image it is interesting to note the presence of involuted caruncles. Note that the mere presence of caruncles does not indicate that this animal had once been pregnant because caruncles are present and easy to see, even in neonatal cattle.
Selected references:
Morton, D.B. and Glover T.D. 1974. Sperm transport in the female rabbit: the role of the cervix. J. Reprod. Fert. 38:131-138
Dobrowolski W and Hafez E.S.E. 1970. Transport and Distribution of Spermatozoa in the reproductive tract of the Cow. J Anim Sci. 31:940-943. This paper is a review article
Note: The author wishes to thank Dr Tammy Muirhead, Dept. of Anatomy, AVC. for her assistance in obtaining these images.
