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

Abstract

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.