Faculty of Veterinary Science
Department of Production Animal Studies
Selected Highlights from Research Findings
Unique features of giraffe anatomy are its long neck and slender long limbs. Its neck vertebrae should be light and have low density to make its neck manoeuvrable while its limb bones should have high density to provide the strength to support its mass. Giraffes also have a very high vertical growth rate, a diet with a high Ca:P ratio and a skeleton that constitutes a high proportion of its body mass. To investigate whether the giraffe skeleton is affected by its anatomy and biology, its bone density and morphology were compared with those of an African buffalo, an artiodactyl of similar mass, more conventional anatomy, a lower vertical growth rate and different diet. It was found that, except for minor differences, the density of giraffe bones is the same as that of buffaloes. Giraffe limb bones have a slightly greater diameter and much thicker walls than equivalent bones in buffaloes. Giraffe cervical vertebrae, unlike those in buffaloes, decrease in mass with cranial distance. Giraffe biology and anatomy therefore do not affect bone deposition or density but other characteristics of their skeletons seem to be adaptations to their unique anatomy.
Contact person: Prof JD Skinner.
It has previously been demonstrated that the pig and African elephant share zona pellucida epitopes, suggesting that it should be possible to use zona pellucida proteins (pZP) to prepare a contraceptive vaccine for elephants. These proteins, isolated from the ovaries of pigs, have also been used successfully for an immunocontraceptive vaccine in horses and a range of wild and captive non-domestic herbivores. The potential to use a pZP vaccine as a contraceptive in free-ranging African elephant populations was therefore investigated in the Kruger National Park and two smaller private game parks. In one experiment only 20% of vaccinated cows became pregnant against 89% in non-vaccinated controls. The trials also proved that the vaccine is safe to use in pregnant animals, that contraception can be maintained by administration of an annual booster and that the cows recover fertility when a booster is not administered. Further studies are needed to determine the long-term effects and the practicality of this and other vaccine candidates, but it seems to offer a solution to the problem of overstocking in game parks.
Contact person: Prof HJ Bertschinger.
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