Special thanks to the following advisors: José Kok MSc, Margje Voeten PhD, Gerard Meijer, Gerard Baars, Peter van der Eijk, Gerry Dorrestein PhD DVM , Andries van Foreest DVM, Klaus Friedrich PhD DVM, Nicole Reens DVM, Frank Viehoff DVM for sharing their valuable knowledge. 

Authors: Koen Cuyten BSc (Alertis) and Jan Bos DVM (Ouwehand Zoo), The Netherlands 

Co-authors: Stijn Peters DVM, Susanne Koot, Sandra Rossen, Charlotte Phauth

Design and illustrations: Associazione Perugia in internet and Koen Cuyten

Technique: Associazione Perugia in internet, Italy