|Topi & Sassabies
Damaliscus lunatus korrigum
1) General Zoological Data
Topis belong to a group of antelopes with curved horns, and the horns are present in both sexes. As a group, these animals are commonly referred to as "Sassabies" (Damaliscus sp.). The group contains three species and perhaps as many as seven subspecies that differ in coloration and size, as well as in chromosomal numbers. In addition to the Topi are the hartebeest (Alcelaphus buselaphus), and bontebok (and the blesbok - Damliscus dorcas, alias hunteri), with some subspecies (Nowak, 1999). Bonteboks in zoological parks are probably not a homogeneous group of animals, probably composed of hybrids between true bonteboks (from that park) with blesboks. It should be emphasized here that there has been considerable dispute of the nomenclature concerning their species designations (see Rookmaker, 1991, and Kumamoto et al., 1996). This is further discussed with respect to the chromosomal patterns under the section on Genetics.
Topis are the most abundant animals of this group of East African antelopes. They weigh around 100 + kg as adults and have strictly defended territories. The growth rate for one topi (Damaliscus korrigum [D. lunatus korrigum]) was charted by Hutchison (1970a). It attained a weight of 132.5 kg at 30 months. The gestational length is about 7-8 months with a single calf being born. Their longevity in captivity is around 20 years. Some subspecies are now very severely endangered and are, therefore, listed as CITES I species.
|Topi at San Diego Wild Animal Park.|
|Two closely related species with dissimilar coloration and stature.|
Sassabies are kept in numerous zoos and they have bred well there.
General Gestational Data
4) General Characterization of the Placenta
|Cross section of a partial cotyledon from a delivered placenta with disrupted maternal floor (inside). Chorion on top.|
|Section of immature, delivered placenta. Chorion on top.|
topi placenta is polycotyledonary; the placenta studied by me had
40 cotyledons that were arranged in four parallel rows. That placenta was
from an immature pregnancy in the third trimester of gestation. It came
from a dam that died with pneumonia, in January. The entire uterus, fetus
with placenta included, weighed 11,575 g. The male fetus weighed 5,450 g
and measured 54 cm in length. The placenta weighed 1,550 g; the uterus weighed
1,150 g; the remainder was fluid. The intact, but opened specimen is illustrated
at the end of the chapter, under Pathology. Only one uterine horn was occupied
by the placenta. Another specimen of Damaliscus l. korrigum had 50
cotyledons, weighed 1,300 g, and came from a Cesarean section after which
the dam died.
In June, 2004, another topi placenta of a term live birth became available. It weighed 1,750 g, had 83 flat cotyledons that were arranged in four rows. They measured up to 12 cm in diameter and 0.5 cm in thickness. The umbilical cord measured 10 cm in length and contained 4 vessels and the allantoic duct. That placenta is shown next.
|New Bontebok placenta with 72 cotyledons arranged in rows.|
|Uterus with placental sac exteriorized.|
|Uterus after removal of the placenta showed the four rows of caruncles.|
|The placenta after removal from the uterus, showing the cotyledons arranged in basically four rows.|
Details of fetal/maternal barrier
Cotyledon of new topi placenta.
|Delivered topi placenta. The maternal floor is disrupted. The chorion is at top.|
|Bontebok placenta at term, edematous perhaps due to prolonged labor and dystocia.|
|Topi placenta attached to uterus, autolyzed. Note the endometrial glands.|
|Bontebok placenta with old hematoma beneath chorion.|
|Bontebok trophoblastic surface of villi with binucleate cell.|
|Portion of umbilical cord with large vein at left and allantoic duct at right. Many small blood vessels are present, some surround the allantoic duct.|
|The surface of the umbilical cord has areas of squamous metaplasia (arrows) that correspond to the verrucae.|
|The thin membranes that separate amnionic and allantoic cavities.|
|Hippomanes in allantoic sac with crystals (arrows) under polarized light.|
Trophoblast external to barrier
|Partial section of neonatal uterus showing one caruncle and adjacent endometrial glands.|
|Higher magnification of fetal endometrium with caruncle.|
|Placenta with fetus in amnion after the allantoic fluid has been released.|
|Fetus exteriorized with small amnionic sac collapsed. Other uterine horn below.|
|Infected bontebok placenta at term with heavy leukocytic infiltration of villi, and necrosis (left).|
|Higher power view of inflamed stem villi.|
|Necrotic, inflamed villus in term bontebok placenta.|
|Cluster of branching fungi in term bontebok placenta (PAS).|
Other remarks - What additional Information is needed?
Griner, L.A.: Pathology of Zoo Animals. Zoological Society of San Diego, 1983.
Hofman, R.R.: Evolutionary steps of ecophysiological adaptation and diversification of ruminants: a comparative view of their digestive system. Oecologia 78:443-457, 1989.
Hutchison, M.: Observations on the growth rate and development of some East African antelopes. J. Zool. 431-436, 1970a.
Hutchison, M.: Artificial rearing of some East African antelopes. J. Zool. London 161:437-442, 1970b.
Kumamoto, A.T., Charter, S.J., Houck, M.L. and Frahm, M.: Chromosomes of Damaliscus (Artiodactyla, Bovidae): simple and complex centric fusion rearrangements. Chromosome Research 4:614-621, 1996.
Nowak, R.M.: Walker's Mammals of the World. 6th ed. The Johns Hopkins Press, Baltimore, 1999.
Puschmann, W.: Zootierhaltung. Vol. 2, Säugetiere. VEB Deutscher Landwirtschafts-Verlag, Berlin, 1989.
Rookmaker, L.C.: The scientific name of the Bontebok. Z. Säugetierk. 56:190-191, 1991.
Wurster, D.H. and Benirschke, K.: Chromosome studies in the superfamily Bovoidea. Chromosoma 25:152-171, 1968.
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