VN March 2023

Vetnews | March 2023 13 Article Regular animal translocations may also help maintain or increase the genetic diversity within the population. Translocations are done by introducing new rhinos of reproductive age into the population. Rhino bulls tend to be very territorial, and introducing new bulls into the population may not be as effective as the dominant bull may deter new bulls from mating. The removal of a territorial bull has also been shown to be an effective tool for increasing the mating of subdominant bulls. Translocations of whole animals can be an expensive procedure and can be stressful on the animal being translocated as well as the new population. Tocombatthefinancialstrainoftranslocations,artificialinsemination can transfer new genetic material into the population without needing to move the animal physically. Artificial insemination further allows the breeder to select the best genetic match for its population and can actively choose to increase genetic diversity. Another advantage of artificial insemination is metaphorically spreading the seeds further without the need to move the animal, resulting in a possible increase in diversity within more than one population. Genetic management of a population further allows populations to be compared to one another and allows for evaluating the overall genetic health of the species. As many populations lack genetic history and have unknown family trees, genetic markers can be used to reconstruct and complete pedigrees to give farmers and reserve managers a better understanding of breeding patterns in the population and the genetic variation within their animals. Although parentage assignment may be compromised in populations with low genetic diversity, manual and software techniques can be used to ensure all possibilities of parentage are considered during data analysis. These techniques often rely on historical data such as calving dates, translocation information and records of territories. The historical data is used in a combined likelihood ratio approach and an exclusion-based approach to determine the genetic relationships to ensure all possibilities of parentage are considered. The genetic identification of the rhino can also be useful in the fight against poaching. As more genetic testing is done on the animals and more profiles of the animals are known, it is easier to link poached products (i.e. rhino horn) with the poached animal. In this case, it may lead to an overview of possible ‘problem areas’ where rhino poachingmay be increasing and can further be used to evaluate vulnerabilities in the anti-poaching strategies. These vulnerabilities can then adequately be addressed by increasing surveillance or relocating the animals to a safer area. The individual identification of rhinos can also deter poachers as the reserve or farm can more easily monitor these rhinos. Increased surveillance of these animals decreases the possibility of poaching, as poachers often prefer animals that are easy to track and kill. Although genetic testing of a population poses to be advantageous to the health of the population and the species, there are several potential downfalls. The cost of genetic testing must be considered and can be an indicator of the type of testing that should be done. Genetic testing of the entire population may be expensive, especially in larger populations. A more conservative approach may be needed where select individuals are tested rather than the whole population. This approach will give an overview of the population and may give insight into the effectiveness of the breeding programme in maintaining genetic diversity. The use of observational data may further strengthen this. The combination of selected genetic testing and observational data can be used as the basis of the breeding programme. A second downfall of genetic testing in rhinos is the need for invasive sampling. Several studies were done using dung samples to evaluate the genetic health of the population as a whole. However, as rhinos tend to share middens and spread their faeces, the genetic material found in the dung middens is often too degraded to use. The collection of samples of adequate quality often requires taking blood or tissue samples of the animals. These techniques usually involve darting or sedating the animals, which may be risky and stressful for the rhinos. It is suggested that biopsy-darting be used to effectively collect animal tissue samples without the added stress of an anaesthetic. Figure 2: Rhinos are often darted to obtain samples adequate for genetic studies. This may put extra stress on the animal and can even lead to death. >>> 14