General veterinarians such as veterinary officers act as experts at court. They are in so far part of the evidence. Due to his experience the veterinary expert shall give systematical uniform principles concerning even domains adjacent to the field of animal protection such as protection of animal epidemics and food cases, verifiable by science and university research. Examples for expert's topics as well as the requirements of expert reports are shown. According to 15 11 Tierschutzgesetz (Animal Protection Act), as well as according to 63, 76 Ordnungswidrigkeitengesetz the experts participation in the proceeding is necessary. In consideration of 74, 22 Strafprozessordnung (Code of Criminal Proceedure) conflicts may arise because the veterinarian officer is self-contained investigator, witness as well as expert in the same proceeding. In general the veterinarian officer, who has been involved in the investigations must be excluded from expert activity in the same case. The veterinarian officers have to solve this problem by seperating tasks and functions within one legal case.