Congo Buffalo

Syncerus caffer nanus (nana)

Order: Artiodactyla
Family: Bovidae

1) General Zoological Data

There is one species of African buffalo, Syncerus caffer. The Forest buffalo that is being considered here, Syncerus caffer nanus, while physically quite different, is generally listed as a subspecies although it is very distinct phenotypically and in its habitat. The Savannah buffalo, Syncerus caffer caffer is the larger, darker species and considered to be an extremely dangerous game animal in Africa. Pohle (2002) described that the aggressiveness in captivity has even led to a number of conspecific deaths. Few zoos keep this species now; there are only three left in Germany that keep this species (Pohle, 2002). Numerous different subspecies have been considered to characterize the intermediate forms; these were reviewed extensively by Grubb (1971) and are also listed by Wilson & Reeder (1992). It appears to me that there is still considerable confusion in this genus with its numerous phenotypes, the formerly wider distribution and, especially, because of the wide variability of karyotypes (52-56) which is atypical for any "good" species. Perhaps the results of mtDNA by Simonsen et al. (1998) give further explanation to these karyotypic varieties. These authors found a "high levels of genetic variability" that did not support suggestions that severe bottlenecks had occurred in recent decades as a possible result of outbreaks of rinderpest. "Hybridization" occurs occasionally between Savannah and Forest buffalos but this alone can hardly account for the wide phenotypic differences.

The Forest buffalo is smaller ("dwarf" = nanus) and has longer red-brown hair; the Savannah species is larger and darker as well as less hairy. In between, but also of Western origin, are red, less hairy buffalos with different names (e.g. S. c. brachyceros). Groves (1981) reviewed what is known of bovid speciation and placed the divergence of Syncerus- from Bos-like ancestors at about 4-5 million years ago. Many zoological gardens exhibit one or the other species. The animals may live up to 30 years.

2) General Gestational Data

Grimsdell (1973) has described the reproductive history of Syncerus. Gestational length is given as between 300 and 345 days, but Sinclair (1977) in his lengthy study, describes it as being on average 340 days. Knechtel (1993) gives 11.2 months as the average length of gestation. Reproduction commences at age 3 years, both for cows and bulls (Pohle, 2002). Singletons are the rule and, in S. c. caffer, newborns weigh around 40 kg. First births are at 4 years and births are spaced by two years.

3) Implantation

Mossman (1987) was emphatic that in all the bovids that he had examined, including the African buffalo, implantation of the umbilical cord occurs mesometrially, in a midcornual location. This indicated to him that this is the place at which the blastocyst comes to rest for elongation and implantation. He also described in considerable detail the development of cotyledons and of the uterine caruncles. In general, this specimen of Syncerus conforms to that description.

4) General Characterization of the Placenta

This is a multicotyledonary, epithelio-chorial placenta with extension over both uterine horns. I have had two specimens available which were, unfortunately somewhat torn and autolyzed. One weighed 2,200 g, possessed 52 very flat cotyledons that measured between 4 and 10 cm in dimension and 0.5 cm in thickness. The cotyledons were larger and more widely spread in the horn occupied by the fetus than in the empty horn. The cord inserted centrally, had 4 vessels and an allantoic duct. It was 9 cm long. The other placenta comes from a 29.9 kg neonate and weighed 2,575 g, measured 217 x 48 cm and had 54 flat cotyledons. They varied from 8 to 6 cm. This umbilical cord measured 28.7 x 0.8 cm. Both specimens were accompanied by hippomanes. Thus, both specimens I have been able to study had fewer cotyledons than are found in cows (+/80) and they were also flatter than seen in cattle (Wild, 1964).

Since this description a neonatal demise following dystocia was recorded. That placenta weighed 2,250 g and had 34 very flat cotyledons measuring up to 6.5 cm. The cord was 35 cm long. The cause of death was probably related to the placental infection shown below.

5) Details of fetal/maternal barrier

As other Bovoidea, Syncerus has a single-layered, single-nucleated trophoblast cover over its villi, with the exception of the typical binucleate cells that are so characteristic for ruminants (Wooding, 1982). These were studied in greater detail by Wooding et al. (1997) and are now considered to produce placental lactogen and other glycoproteins. Their glycoprotein molecule production was studied by Atkinson et al. (1993) but their usefulness is as yet unknown.

6) Umbilical cord

One of the umbilical cords measured 9 cm, the other 28.7 cm. They had four large blood vessels and a central allantoic duct. The cords had essentially no Wharton's jelly, no twists and no other unusual features. The last specimen received following Cesarean section had a 35 cm long umbilical cord.

7) Uteroplacental circulation

This has not been described for this species.

8) Extraplacental membranes

Both placentas had a 5 cm large yellow hippomanes. They were found in the long, narrow allantoic sac that is typical for this species. They consisted of central amorphous material with a coating of numerous colorless crystals. The trophoblastic epithelium as well as the amnionic epithelium of both placentas was autolyzed.

9) Trophoblast external to barrier

Since no implanted placenta has been available, no judgment can be made as to uterine trophoblast infiltration. Considering other bovid specimens, however, invasion of the endometrium is unlikely in this species as well.

10) Endometrium

Unknown.

11) Various features

Unknown.

12) Endocrinology

Females have a 23 day estrous cycle and estrus lasts 5-6 days.

13) Genetics

The Congo buffalo, Syncerus caffer nanus, was thought to have 54 chromosomes when we examined specimens from the Catskill Game Farm, while its relative, Syncerus caffer caffer had 52 chromosomes (Wurster & Benirschke, 1968). The difference being a Robertsonian fusion element, # 3, in the latter. Consequently it was not surprising that the only male hybrid whose chromosomes have been reported had 53 chromosomes (Cribiu & Popescu, 1980). Since then, however, other animals studied in our laboratory and coming from different institutions, have shown to possess different karyotypes (2n=54-56). The problem with most of these animals is that the precise place of origin of the animals studied is unknown. Several hybrids of forest and "East African buffalo" ("S. caffer aequinoctialis") were also produced at the Paris Zoo (Gray, 1972). It is unusual for a "good species" to have this wide a range of karyotypes and more work with animals of known locality of origin is needed. Moreover, it would be important to know whether putative "hybrids" are fertile. The chromosome number of the specimen examined here was 2n=55 (XX).

Simonsen et al. (1998) studied the mtDNA control region of various populations of African buffalo and found high levels of genetic variability.

14) Immunology

There are no reports of immunologic studies. Sporadic reports of the presence of antibodies in buffalos have been published. Thus, Shepherd et al. (1987) found antibodies against "Crimean-Congo hemorrhagic fever" in 56 of 287 specimens of African buffalo. In a later study (Burt et al., 1993) expanded their study with modern antibodies and ascertained the persistence of antibodies in sheep. The virus is transmitted by an adult tick (Hyalomma) that is known to use buffalo as one of many hosts.

15) Pathological features

It is believed that the savannah buffalo serves as reservoir of foot-and-mouth disease in Africa (Vosloo et al., 2002). Syncerus also serves as an important reservoir of Mycobacterium bovis (Grobler et al., 2002). Attempts at removing infected animals are in progress. Nevertheless, the disease is often spread to cattle and other domestic species and remains to be a serious health problem (Michel, 2002). Huchzermeyer et al. (2001) autopsied a number of animals, including forest buffalos, in the Congo Republic. They determined that infection with Elaeophora sagitta had caused exsanguinations, and exhaustion was finally caused by an "unusual plague of Stomoxys omega". Griner (1983) recorded trauma, enteritis and neonatal malnutrition from lack of maternal lactational care as causes of deaths.

The placenta of the stillborn shown above was remarkable in that one half was perfectly normal, with well-preserved cotyledons and showing no inflammation; the darker cotyledons were massively congested and had large colonies of bacteria in villi and there was acute inflammation associated with these colonies, and located in the villous structures.

16) Physiologic data

Pospisil et al. (1985) published the results of their hematologic studies of both buffalo species. Red cell counts decreased with age, while the percentage of eosinophils increased.

17) Other resources

Many cell lines of African buffalos are available from CRES at the San Diego Zoo by contacting Dr. Oliver Ryder at oryder@ucsd.edu.

18) Other remarks - What additional Information is needed?

This specimens were too autolyzed for a proper histological study. Because of the thin, flat nature of cotyledons and the seemingly large areas of connective tissue in the placenta, studies of implanted placentas is badly needed. There is a need to better define the chromosomal features of animals from know regions in Africa, known phenotypes, and of hybrids.

Acknowledgement

The animal photographs in this chapter come from the Zoological Society of San Diego. I appreciate also very much the help of the pathologists at the San Diego Zoo.

References

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