Exploration of double-dart injection technique as a supplemental application for remote drug delivery system for zoo and wild animals

Background and Aim: Remote drug delivery has become an essential tool for safely delivering medication and vaccines to free-ranging, non-domestic, or dangerous animals. All dart guns currently use a single dart per injection, and it might occasionally be not practical with large animals. Shooting the dart more than once on an animal may cause flight, injury, stress, and ultimately unsuccessful delivery. Furthermore, purchasing many dart guns and hiring and training more staff may be unfeasible in developing countries. Therefore, employing the double-dart injection technique may help reduce the cost of operation, save time for capturing animals, minimize stress and injury, and improve animal welfare. The objectives of this study were to test the possibility of using the double-dart injection technique and optimizing the guidelines for this procedure. Materials and Methods: A standard brand-calibrated darting rifle was used to deliver the darts to the target board constructed from paper, polypropylene, and ethylene-vinyl acetate foam. The shot stage and shooter were fixed, and the shooting range was 5-20 m. The pressure of the gun was varied according to a company's recommendation. The single dart (control dart) was first shot to the target point, and then the double darts were shot 3 times for each condition. The experiment was done in the field with no wind. The inclusion criteria were that two darts must hit the target and not penetrate the target board deeply. The distances between the control dart and double darts (first and second darts) and between each dart of the double darts were measured, and the standard curve graphs and formulas were created. Results: The results showed that the distance between the control dart and the double darts was shortened as the pressure was increased. All double-dart injections hit the target below the control dart. We were able to create many formulas to predict the optimal gun pressure and aim point for double-dart injection in each shot range. It usually requires more pressure settings than a single-dart injection, particularly the long shot range. It also needs to aim the target point above the original point. Conclusion: Double-dart injection technique can be used efficiently in 5-20 m distance, and it usually requires increasing the pressure from the company's recommendation and adjusting the injecting point.