Accelerated induction of etorphine immobilization in blue wildebeest (Connochaetes taurinus) by the addition of hyaluronidase

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 Studiesunrestricte

Accelerated induction of etorphine immobilization in blue wildebeest (Connochaetes taurinus) through the addition of hyaluronidase

OBJECTIVE : To study the effects of the addition of hyaluronidase (HA) to an etorphine/azaperone drug combination on induction times of immobilization. STUDY DESIGN : Experimental part-randomized 'blinded' cross-over study. ANIMALS : Eight wild managed blue wildebeest (Connochaetes taurinus). METHODS : Animals were immobilized, on separate occasions separated by two weeks, with one of four treatments. Treatments were; 'Control drugs (CD), etorphine 0.01 mg kg(-1) + azaperone at 0.1 mg kg(-1) ; treatment 1 CD + 5000IU HA; treatment 2 CD + 7500 IU HA; and treatment 3 etorphine 0.007 mg kg(-1) + azaperone at 0.07 mg kg(-1) + 7500 IU HA. Times to first effect and to immobilization (from darting to possible to approach and blindfold) were measured. anova was used to compare treatments. Results are given in means ± SD (range). RESULTS : For control, and treatments 1-3 respectively, times (in minutes) to first effect were 1.58 ± 0.42 (1.02-2.10), 1.64 ± 0.42 (0.95-2.17), 1.12 ± 0.24 (0.80-1.48) and 1.60 ± 0.21 (1.13-1.88) and to immobilization were 5.38 ± 1.53 (3.82-8.07), 3.80 ± 1.14 (2.02-5.50), 3.51 ± 1.08 (2.28-5.52) and 4.46 ± 0.67 (3.30-5.40). Compared to control, time to first effect for treatment 2 was significantly shorter. Time to immobilization was significantly quicker in all three treatments containing HA than that for control. CONCLUSION AND CLINICAL RELEVANCE : Hyaluronidase can reduce the time to immobilization when used in the immobilizing dart, and might be usefully incorporated into etorphine combinations for darting wildlife.University of Pretoria and the South African Veterinary Foundation.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1467-29952016-03-31hb201