The physiological effects of etorphine, and etorphine combined with xylazine and etorphine combined with azaperone on respiratory and cardiovascular function were determined in. Boer goats. The goats were habituated to the experimental procedures allowing the determination of respiratory and cardiovascular function while the animals stood quietly at rest. This resulted in the physiological changes induced by the three immobilizing drugs being measured and compared with those obtained prior to the administration of the immobilizing drugs. The: effectiveness of diprenorphine and atipamezole in antagonising the physiological changes induced by the immobilizing drug treatments was also determined. All three immobilizing drug treatments depressed respiratory function resulting in a decrease in PaO2and an increase in PaCO2. Etorphine caused limited changes to these blood gases as a result of decreases in respiratory minute volume and alveolar minute ventilation caused by a fall in respiratory rate. The administration of etorphine / azaperone did not decrease the efficiency of respiration more significantly than when etorphine was administered on its own. Etorphine injected in combination with xylazine resulted in a severe decrease in respiratory function. The decrease in PaO2 and the increase in PaCO2 were much greater than the changes to these two blood gases following the administration of either etorphine or etorphine in combination with azaperone. Compared to etorphine administered on its own, etorphine combined with xylazine caused more significant decreases in tidal volume and alveolar minute ventilation, and more significant elevations in both physiological shunt fraction and percentage dead space ventilation. The administration of etorphine, etorphine / xylazine and etorphine / azaperone caused three different sets of changes to cardiovascular function. The injection of etorphine resulted in significant increases in both total peripheral resistance and systemic mean arterial blood pressure, and a significant decease in cardiac output. The administration of etorphine / xylazine resulted in a rapid and significant decrease in the systemic mean arterial blood pressure, followed by a decrease in cardiac output. The peripheral resistance remained unchanged. Etorphine / azaperone caused a progressive decline in the total peripheral resistance. As the cardiac output did not change significantly, the systemic mean arterial blood pressure fell progressively. The administration of etorphine resulted in a gradual and limited decrease in the oxygen consumption index. Following the injection of etorphine / xylazine a rapid and significant decrease in the oxygen consumption index resulted, which was significantly lower, when compared to the goats immobilized with etorphine, at 5 and 35 minutes PDA. The injection of etorphine / azaperone resulted in a gradual decrease in the oxygen consumption index which reached a minimum value at 35 minutes PDA. At this time, the oxygen consumption index due to etorphine / xylazine was not significantly different from the value due to etorphine / azaperone. Diprenorphine effectively reversed the respiratory and cardiovascular effects due to etorphine. The physiological changes induced by the administration of etorphine / xylazine were partially and temporarily antagonised by the administration of diprenorphine, it was only following the injection of atipamezole that they return to the values measured in the goats prior to immobilization. Diprenorphine effectively reversed the respiratory depression induced by etorphine / azaperone, however a mild acidosis persisted until the end of the trial period. The cardiac output and systemic mean blood pressure improved dramatically following the injection of diprenorphine but there was no immediate change in total peripheral resistance. / Dissertation (MMedVet)--University of Pretoria, 2010. / Animal and Wildlife Sciences / unrestricted

Wild animal capture has progressed over the years from trapping or physical capture, which was dangerous to both animal and man, to chemical immobilization. Opioids and butyrophenones are the most common classes of drugs used for ungulate immobilization; however newer drugs and drug combinations are commonly used in an attempt to reduce time to immobilization in wildlife. The enzyme hyaluronidase is often added to drug combinations in the belief that it reduces time to immobilization by improving drug absorption. The primary objective of this study was to ascertain if the addition of hyaluronidase to an etorphine and azaperone drug combination would be of value in reducing time to immobilization in blue wildebeest. The study also tried to ascertain if the added hyaluronidase enabled one to reduce the etorphine and azaperone doses required to immobilize blue wildebeest, without affecting time to immobilization. The study made use of a four-way cross-over study design, with four treatment groups, four sequences and four periods. The four treatment groups were etorphine and azaperone; etorphine, azaperone and 5000 international units (IU) hyaluronidase; etorphine, azaperone and 7500 IU hyaluronidase; and 75 % of the original etorphine dose, 75% of the original azaperone dose and 7500 IU hyaluronidase. Each animal was immobilized with each of the above four drug combinations randomly over an eight week period with a two week interval between each period. The times to first effect, first down and immobilization were recorded. The etorphine and azaperone treatment group was used as the control group. The difference in time to first effect between the control group and the etorphine, azaperone and 7500 IU hyaluronidase treatment group was statistically significant (95 seconds versus 67 seconds; p = 0.007). When compared to the time to immobilization in the control group (323 seconds) the time to immobilization in the etrophine, azaperone and 5000 IU hyaluronidase (228 seconds); etorphine, azaperone and 7500 IU hyaluronidase (210 seconds) and the low dose etorphine, low dose azaperone and 7500 IU hyaluronidase (268 seconds) groups were statistically significantly reduced (p=0.002, p=0.001 and p=0.045 respectively). It is therefore concluded that the addition of 5000 or 7500 IU hyaluronidase to an etorphine and azaperone combination significantly reduced the time to immobilization in blue wildebeest. The unexpected decrease in time to immobilization in the low dose etorphine, low dose azaperone and 7500 IU hyaluronidase treatment group requires further investigation. / Dissertation (MMedVet)--University of Pretoria, 2011. / Production Animal Studies / unrestricted