Little has been done to assess veterinarians' moral judgment in relation to animal ethics issues. Following development of the VetDIT, a new moral judgment measure for animal ethics issues, this study aimed to refine and further validate the VetDIT, and to identify effects of teaching interventions on moral judgment and changes in moral judgment over time. VetDIT-V1 was refined into VetDIT-V2, and V3 was developed as a post-intervention test to prevent repetition. To test these versions for comparability, veterinary and animal science students (n=271) were randomly assigned to complete different versions. The VetDIT discriminates between stages of moral judgment, condensed into three schemas: Personal Interest (PI), Maintaining Norms (MN), and Universal Principles (UP). There were no differences in the scores for MN and UP between the versions, and we equated PI scores to account for differences between versions. Veterinary science students (n=130) who completed a three-hour small-group workshop on moral development theory and ethical decision making increased their use of UP in moral reasoning, whereas students (n=271) who received similar information in a 50-minute lecture did not. A longitudinal comparison of matched first- and third-year students (n=39) revealed no moral judgment development toward greater use of UP. The VetDIT is therefore useful for assessing moral judgment of animal and human ethics issues in veterinary and other animal-related professions. Intensive small-group workshops using moral development knowledge and skills, rather than lectures, are conducive to developing veterinary students' moral judgment.
Keywords: animal ethics; ethics education; ethics workshop; moral judgment; veterinary ethics.