Efficiency and safety of xylazine and tiletamine/zolazepam to immobilize captured wild boars (Sus scrofa L. 1758): analysis of field results

Abstract

During a 2-year study on wild boar ecology in a semiagricultural area of Northern Apennines (central Italy), 47 animals were caught with traps and subsequently immobilized with chemical restrain based on a 1:1 mixture of xylazine and tiletamine/zolazepam (1 ml contains: 50 mg of xylazine, 25 mg of tiletamine, and 25 mg of zolazepam). Effective chemical immobilization was observed in 55% of the caught wild boars, and a high capture mortality rate occurred (in 10.6% of wild boars). A posteriori analysis, by means of a logistic regression model, was performed to assess potential factors associated with wild boar chemical immobilization failure. Underdosage and increase in the number of animals caught together significantly increase the wild boar chemical restrain failure, while the capture mortality appears to be positively related to the sole trap size alone. The stress developed during the capture plays a relevant role influencing the outcomes of the anesthesia. Thus, the use of alternative handling or catching procedures with the aim to reduce stress in captured animals could maximize the safety and the efficiency of the wild boar chemical immobilization.