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| Location: |
World |
| Subject: |
Anatomy - Reproductive organs |
| Species: |
African Rhino Species |
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Over the past year, several reproductive tracts from female black and white rhinos have been obtained at necropsy. It appears that the major obstacle to be overcome is the overall length of the tract. In mature black and white rhinos, the entire tract was approximately 100 cm in length. The distance from the vulva to the cervix averaged 40 cm in length. The cervix itself was not exceedingly long (averaging 14 cm), but the path through the cervix appeared extremely tortuous. The cervical canals of three mature rhinos (one black, two white) contained five to six folds of tissue which formed eccentric rings. The cervical lumen contained several 90? turns and blind pockets which could be difficult to navigate with a catheter for placement of semen or collection and placement of embryos.
All of the tracts collected had a constriction in the posterior urogenital canal, just anterior to the urethra. This hymenal membrane was in various states of patency which appeared to be related to age and parity of the animal. The older animals had large (1 to 3 cm) perforations in the membrane, while the hymen in a 7-day-old caff tract contained much smaller holes (< 1 mm). A primiparous white rhino examined had remnants of a hymen visible in the tract at the same location of the intact membrane in the other tracts.
Two of the older animals (one 28-year-old black rhino and a 27-year-old white rhino) had what appeared to be hyperplasia of the endometrium. It was more pronounced in the white rhino uterus, but the animal had been stimulated with exogenous hormones (gonadotropins and progestins) which may have accentuated this condition. The hyperplasia was not as pronounced in the black rhino tract, but it was uniform throughout both uterine horns, as in the white rhino tract. It is uncertain if this condition is related to the fertility of these animals. Another white rhino (21-year-old, primiparous) did not exhibit any signs of endometrial hyperplasia. It was also not apparent in the 3-year-old and 7-day-old black rhino tracts.
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Up to my ears in rhinos
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