Browsing by Author "Laubscher, Liesel L."
Now showing 1 - 3 of 3
Results Per Page
- ItemComparing the effects of tranquilisation with long-acting neuroleptics on blue wildebeest (Connochaetes taurinus) behaviour and physiology(Stellenbosch : Stellenbosch University, 2015-12) Laubscher, Liesel L.; Hoffman, Louwrens C.; Pitts, Neville I.; Raath, Jacobus P.; Stellenbosch University. Faculty of Agrisciences. Dept. of Animal Sciences.ENGLISH ABSTRACT: In South Africa, large numbers of game animals are translocated annually. These animals are subjected to a great amount of stress and the use of long-acting neuroleptics (LANs) has become a common practice to minimize animal stress. Long-acting neuroleptics suppress behavioural responses without affecting spinal and other reflexes, and can be administered in such a manner that a single dose results in a therapeutically effective tissue concentration for anywhere between three to seven days. The mammalian stress response consists of a variety of physiological responses, and the study aimed to quantify a number of these responses in blue wildebeest (Connochaetes taurinus). This was done in order to compare the effects of a commonly used LAN, Acuphase® (zuclopenthixol acetate in vegetable oil), with a newly developed LAN, Acunil® (zuclopenthixol acetate in a low-release polymer), in minimizing the stress response of blue wildebeest in captivity. A human biotelemetry belt, Equivital™ EQ02, was modified to fit this species, and the results from a validation study indicated that the belt accurately measured heart and respiration rate, respectively, in blue wildebeest. The belt also measured motion accurately, and this made the monitoring of conscious animals prior to and after being treated with a LAN, possible. A faecal glucocorticoid metabolite (FGM) assay was also validated for use in blue wildebeest. Three sets of trials were performed in which animals received one of three treatments; Acuphase®, Acunil® or a placebo in order to evaluate the effect of each. Animals were monitored for 12 hours before and 12 hours after treatment. The results showed that although both Acuphase® and Acunil® resulted in a decrease in vigilant behaviour and an increase in resting behaviour, similar results were observed when animals received a placebo. Animals treated with Acunil®, however, exhibited a decrease in explorative behaviour as well as an increase in the time they spent eating. Heart rate was unaffected by any of the three treatments, and this lack of effect by either of the LANs may potentially be due to reflex tachycardia in response to hypotension. Respiration rate was lowered by both LANs, specifically during certain behaviours, with this effect being absent in placebo-treated animals. In addition, the motion of the animals indicated that LAN-treated animals had a lowered flight response to a person entering the enclosure. Endocrine parameters measured in the blood and faeces of the animals before and after treatment revealed a minimal effect. Neither the acute nor the chronic stress response appeared to be significantly reduced by treatment with Acuphase® or Acunil®. In addition, immune function (as quantified by white blood cell count and neutrophil response) revealed that the chronic stress of captivity lowered the immune response of the animals. This decrease in immunocompetence, however, could not be ascribed to any of the LAN treatments. In conclusion, the most pronounced effects observed with the administration of both LANs included a decrease in respiration rate, and responsiveness of the animals. Long term studies on the effect of LAN administration on immune function and endocrine responses may yield more conclusive results regarding the stress responses of wild animals in captivity.
- ItemThe effect of different cropping methods on the meat quality of various game species(Stellenbosch : University of Stellenbosch, 2009-03) Laubscher, Liesel L.; Hoffman, Louwrens C.; University of Stellenbosch. Faculty of Agrisciences. Dept. of Animal Sciences.ENGLISH ABSTRACT: The production and especially the export of game meat from Southern African are steadily increasing and with this growth, it is inevitable that more emphasis is being placed on the quality of game meat. Research regarding the effect of different cropping methods on ante-mortem stress, and as a result, on meat quality in wild ungulates, is lacking and thus the purpose of this study was to investigate the effect of some of the commonly used cropping methods on the meat quality of red hartebeest, impala, gemsbok and kudu. Antemortem stress was measured using serum cortisol levels (nmol/L), a subjective stress score allocated to each animal as well as the rate and extent of pH decline in the M. longissimus dorsi. Special emphasis was also placed on the meat quality parameters drip loss, cooking loss, colour and Warner-Bratzler shear force (kg/1.27 cm diameter). The effect of day and night cropping on the meat quality of red hartebeest, gemsbok and kudu was investigated. An exponential decay model, y = a + b-ct, was fitted to the pH data of the gemsbok and red hartebeest, and pHu measurements taken at 24 hours post-mortem. Only pHu readings taken at 48 hours post-mortem were analysed in the kudu. Day-cropped kudu had a lower mean pHu (5.40 ± 0.030) than nightcropped kudu (5.48 ± 0.041). No differences in pHu were found for the red hartebeest although night-cropped gemsbok had a higher mean pHu (5.54 ± 0.013) than day-cropped gemsbok (5.49 ± 0.014). None of the constants of the exponential decay model differed for the red hartebeest although day-cropped gemsbok produced a lower constant than night-cropped gemsbok. Mean stress scores and cortisol levels were found to be higher in day-cropped animals for both the gemsbok and kudu while only cortisol levels were higher in die day-cropped red hartebeest. Stress score and cortisol levels were found to be correlated in all three species (red hartebeest: r = 0.51; gemsbok: r = 0.786; kudu: r = 0.823). No treatment differences in drip loss or cooking loss were found for either the red hartebeest or gemsbok, while day-cropped kudu had a higher mean drip loss % (2.76 ± 0.261%) than night-cropped kudu (1.36 ± 0.361%). Night-cropped gemsbok and kudu produced higher mean shear force values (gemsbok = 4.19 ± 0.138; kudu = 4.06 ± 0.237 kg/1.27 cm diameter) than day-cropped animals (gemsbok = 3.57 ± 0.154; kudu = 3.45 ± 0.171 kg/1.27 cm diameter). Colour differences indicated that day-cropped gemsbok and kudu produced lighter meat than night-cropped animals. The results indicate no difference in the effects of day and night cropping in red hartebeest although day-cropped gemsbok and kudu experienced more ante-mortem stress than their night-cropped counterparts. The effect of conventional hunting during the day and night cropping on impala meat was also investigated. No differences were found in pH45 or pHu (taken at 45 minutes and 24 hours post-mortem respectively) although the exponential decay model, y = a + b-ct, fitted to the pH data revealed differences in all the constants (day: a = 5.424 ± 0.039, b = 1.405 ± 0.034, c = -0.385 ± 0.022; night: a = 5.295 ± 0.033, b = 1.556 ± 0.029, c = -0.184 ± 0.019). No differences were found for drip loss, cooking loss or shear force although day-cropped animals produced higher a* and chroma values. The results indicate that, although conventional hunting caused a faster and more severe post-mortem pH decline, both treatments produced meat of similar quality.
- ItemAn overview of disease-free buffalo breeding projects with reference to the different systems used in South Africa(MDPI AG, 2012-11) Laubscher, Liesel L.; Hoffman, Louwrens C.This paper describes the successful national program initiated by the South African government to produce disease-free African buffalo so as to ensure the sustainability of this species due to threats from diseases. Buffalo are known carriers of foot-and-mouth disease, bovine tuberculosis, Corridor disease and brucellosis. A long-term program involving multiphase testing and a breeding scheme for buffalo is described where, after 10 years, a sustainable number of buffalo herds are now available that are free of these four diseases. A large portion of the success was attributable to the use of dairy cows as foster parents with the five-stage quarantine process proving highly effective in maintaining the “disease-free” status of both the calves and the foster cows. The projects proved the successfulness of breeding with African buffalo in a commercial system that was unique to African buffalo and maintained the “wildness” of the animals so that they could effectively be released back into the wild with minimal, if any, behavioral problems.