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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A systematic review of helminth infections of tragelaphine antelopes in Africa

Cilliers, Maruchelle January 2019 (has links)
The tragelaphine antelopes comprise a group of nine species, namely Tragelaphus eurycerus (bongo), Tragelaphus scriptus (bushbuck), Tragelaphus oryx (common eland), Tragelaphus derbianus (giant eland), Tragelaphus strepsiceros (greater kudu), Tragelaphus imberbis (lesser kudu), Tragelaphus buxtoni (mountain nyala), Tragelaphus angasii (nyala) and Tragelaphus spekii (sitatunga) which are all confined to the African continent. Currently, a total of 72 species of helminth parasites from seven tragelaphine antelope species have been recorded, while no records exist for T. imberbis and T. buxtoni. Some helminth species are shared with domestic stock and only a few helminths have zoonotic implications. The clinical significance of most helminth species in tragelaphine antelopes is unknown. This information was compiled based on an extensive search for records in the literature ranging from the early nineteen-hundreds until August 2019. A synopsis of the results is presented in tabular form. / Mini Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Unrestricted
2

Ontogenetic allometry of the postcranial skeleton of the giraffe (Giraffa camelopardalis) with application to giraffe life history evolution and palaeontology

Van Sittert, Sybrand Jacobus January 2015 (has links)
Giraffes (Giraffa camelopardalis) have evolved into a unique and extreme shape. The principle determinant of its shape is the skeleton and the overarching theme of the study was to describe how this shape is achieved throughout ontogeny. Accordingly, the study had three main objectives: 1) To describe the growth of the giraffe postcranial skeleton allometrically, 2) To interpret the allometric patterns described in an evolutionary and functional sense and 3) To reconstruct the size and shape of the extinct Giraffa sivalensis using, if feasible, allometric equations obtained in this study. Secondary objectives were to a) establish if sexual dimorphism was evident in G. camelopardalis and b) determine if growth patterns in the foetus differed from those in postnatal G. camelopardalis. Data were collected from giraffes culled as part of conservancy management in Zimbabwe. The sample included 59 animals from which vertebral dimensions were taken in 48 animals and long bone dimensions in 47 animals. Body masses ranged from 21 kg to 77 kg in foetuses and 147 kg to 1412 kg postnatally, representing 29 males and 30 females. In addition to body mass, external body dimensions were recorded from each animal. Each vertebra and unilateral long bone was dissected from the carcasses and cleaned, after which dimensions were measured with a vernier calliper, measuring board or measuring tape. Vertebral dimensions measured included body (centrum) length, height and width as well as vertebral spinous process length. Long bone dimensions included length, two midshaft diameters and circumference. Allometric equations (y=bxk) were constructed from the data, with special interest in the scaling exponent (k) to illustrate regions of positively allometric, isometric or negatively allometric growth. In the first series of analyses the growth patterns of the components of the postcranial axial skeleton were analysed. The adaptations in vertebral growth to create and maintain extraordinary shape were identified as disproportionate elongation of the cervical vertebrae after birth, increasing cross sectional diameters of the cervical vertebrae from cranial to caudal and positively allometric spinal process growth. The theory of sexual selection as a driver for neck elongation in giraffes was brought into question by showing that male and female vertebral elongation rates are similar relative to increases in body mass. The second series of analyses described the growth pattern of the long bones of the appendicular skeleton. The allometric exponents seemed unremarkable compared to the few species described previously, and it was shown that the giraffe appendicular skeleton does not elongate in the dramatic way the neck does. Limbs at birth, after lengthening with positive allometry in utero, are already elongated and slender in shape and a further increase in the gracility of the bones is either not possible or not desirable. This result implies that it is neck elongation rather than leg elongation that is the dominant factor in the evolution of the giraffe shape. Nevertheless, the front limb bones and especially the humerus may show responsiveness to increasing high loads and/ or bending moments, which may be caused by the neck mass which increases with positive allometry, or with behaviours such as splaying the forelegs during drinking. In the third component of the study ontogenetic allometric equations in extant giraffes were applied to the remains of an extinct giraffid, G. sivalensis. The procedure was unusual as it employed ontogenetic regressions instead of the more commonly used interspecific regressions. The appropriateness of each equation to estimate body mass was evaluated by calculating the prediction error incurred in both extant giraffes and okapis (Okapia johnstoni). It was concluded that, due to body shape, ontogenetic equations were adequate and perhaps preferable to interspecific equations to estimate proportions in Giraffa species. This analysis showed that G sivalensis was smaller than extant giraffes and weighed around 400 kg (range 228 kg 575 kg), with a neck length of about 147 cm and a height of 390 cm. There may be evidence of sexual dimorphism in this species, with males being about twice the body weight of females. However, if sexual dimorphism was not present and all the bones were correctly attributed to this species, then G. sivalensis had a slender neck with a relatively stocky body. In conclusion, this study established ontogenetic regression equations for the skeleton of an animal of which the body shape seems to be at the extreme limits of mammalian possibility. The value of the current study lies especially in its sample size and quality, which included an unprecedented number of giraffe body masses, vertebral and long bone dimensions. This dataset had applications in the giraffe s evolutionary biology, palaeontology and even ecology. Future studies still need to compare the findings from giraffe growth with similar data from other taxa, especially those with long legs and necks. Specifically, it would interesting to determine if positively allometric neck growth combined with isometric leg growth is found in other mammalian species. In addition, the strength of giraffe long bones and vertebrae needs to be investigated with more accuracy using parameters like second moment of area. Lastly, further palaeontological studies on other giraffid sizes are necessary to validate the current and future interpretations of fossil giraffid findings. / Thesis (PhD)--University of Pretoria, 2015. / tm2016 / Production Animal Studies / PhD
3

Monitoring adrenocortical function as a measure of stress in blue wildebeest (Connochaetes taurinus)

De Haast, Adel Riette January 2016 (has links)
Like many other wildlife species, blue wildebeest (Connochaetes taurinus) are routinely captured for relocation purposes. Several studies have shown that physiologically this is a very stressful period for wild animals and can affect several aspects of their well-being. Little is known about the level of physiological stress experienced by blue wildebeest during capture and confinement before transport. A non-invasive approach to assess adrenocortical function as a measure of physiological stress would be preferable, as animals are not disturbed during sample collection, and therefore sampling is feedback free. Currently, however, such a non-invasive measure has not been evaluated for any wildebeest species. An adrenocorticotropic hormone (ACTH) challenge test was performed on one sub-adult male and one adult female. We examined the suitability of five enzyme immunoassays (EIAs), detecting faecal glucocorticoid metabolites (fGCM) with a 5?-3?-ol-11-one (3?,11oxo-CM), 5?-pregnane-3?,11?,21-triol-20-one (37e), 11?,21-diol-20-one (corticosterone), 11,17,21-trihydroxypregn-4-ene-3,20-dione (cortisol), and 11,17-dioxoandrostane (11,17-DOA) structure respectively, for monitoring stress-related physiological responses in blue wildebeest. After evaluating all five EIAs, it was concluded that the EIA measuring 11,17-DOA performed the best for detection of fGCMs in blue wildebeest with a 21 fold increase above the baseline in the male and a 4,7 fold increase above the baseline in the female at 12 hours post ACTH injection. Under field conditions the use of the 11,17-DOA EIA allowed the monitoring of fGCM alterations when wildebeest were captured using a mass capture technique; fGCM concentrations were elevated by 1,5 times in samples collected from animals restrained for up to 10 hours in a truck compared to those collected directly after capture (P <0,001). No significant increase in fGCM concentrations was detected in faecal samples collected directly after capture from animals of the same herd captured either on day 1 or day 2 of mass capture, indicating that the presence of a helicopter during the two days of capture was not associated with a profound stress response in wildebeest that were not captured at the time but were in the vicinity of the capture. Storage of faeces in labelled plastic containers at ambient temperature for up to 48 hours post-defecation resulted in a significant decrease in 11,17-DOA levels from 8 to 48 hours after defecation. Therefore sample collection for 11,17-DOA determination in wildebeest can occur for up to 8 hours post-defecation without the risk of substantial decreases in 11,17-DOA concentrations. By identifying a suitable assay for determining 11,17-DOA concentrations in blue wildebeest, it can now be used by researchers, wildlife managers and veterinarians to reliably monitoring the physiological stress responses to capture or other management procedures with minimum interference to the animals. We have also shown that the presence of a helicopter during capture does not appear to have a lasting influence on wildebeest 11,17-DOA concentrations, but prolonged restraint for 10 hours does. / Dissertation (MSc)--University of Pretoria, 2016. / Paraclinical Sciences / MSc / Unrestricted
4

Determination of the pathophysiological consequences of capture and capture-induced hyperthermia in blesbok (Damaliscus pygargus phillipsi)

Fitte, Agustina January 2016 (has links)
An unacceptable number of wild animals die or experience morbidity as a result of capture-related complications. Capture-induced hyperthermia is believed to play a role in the morbidity and mortality of captured animals. The aims of this research were to gain a better understanding of the pathophysiological consequences of capture and capture-induced hyperthermia and to better understand the association between capture-induced hyperthermia and capture myopathy. We aimed to determine whether cooling could reduce the pathophysiological consequences of capture and protect against capture related complications like capture myopathy. Forty wild blesbok were captured from the wild and then housed in bomas at Groenkloof Nature Reserve for the duration of the study. These animals were divided into three groups which included a group of animals that were chased and cooled during immobilization (C+C), a group that was chased but not cooled during immobilization (CNC) and a control group that was not chased before or cooled during immobilization (Ct). The control group received powder diazepam in their feed two hours before they were darted to minimize their stress response to capture. The treatment groups were chased for 15 minutes before they were darted. All the animals were darted and immobilized with etorphine and azaperone. The chased and cooled group were doused with 10L of 4°C water over a 10 minute period during the immobilization. The immobilization period lasted for forty minutes in all the animals. A number of clinical and physiological parameters were measured in all the animals directly after induction into immobilization, 40 minutes later, and then on day 2, 16 and 30 post the initial capture. On these subsequent days the animals were not chased but they were simply all immobilized in their holding bomas, for data and sample collection, after they received in feed diazepam. The parameters measured and analysed included muscle and rectal temperature, PaO2, PaCo2, pH, lactate, GGT, GLDH, creatinine, BUN, CK, AST, cardiac troponin I and cortisol. The animals in the control group had normal values for all the variables measured except they were hypoxic during the immobilization. The animals that were chased developed hyperthermia, hypoxia and mild acidaemia, and they had mildly elevated concentrations of GLDH, AST, CK and creatinine indicating mild hepatic, renal and skeletal muscle damage. These animals also had severe increases in lactate and cardiac Troponin I concentrations indicating cardiac damage possibly as a result of the hypoxia that occurred during the chase and the immobilization. Despite cooling correcting the hyperthermia, it did not prevent or protect against any of these pathophysiological effects. Therefore, this capture-induced hyperthermia appeared to play a limited role in causing these effects. Therefore, capture that involves chasing animals before immobilization appears to primarily cause cardiac muscle damage. This capture-induce cardiomyopathy may have profound secondary consequences, which could result in mortality or other capture related complications. / Dissertation (MSc)--University of Pretoria, 2016. / Paraclinical Sciences / MSc / Unrestricted

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