Effect of different management protocols for grouping does on aggression and dominance hierarchies

The study aimed at evaluating different management protocols of grouping does in regard to aggressive interactions and the establishment of a hierarchy under commercial conditions. Fifty-seven multiparous rabbit does of the Hycole hybrid maternal line were randomly distributed into three different management protocols (MP) for a total of 5 consecutive trials: MP12 with grouping 12 days after parturition, MP18 after 18 days and MP22 after 22 days. Video recordings were made during the first 24 h after grouping and after 6 and 10 days, and used to score aggressive interactions of the animals with exception of treatment 3 where day 10 was omitted because it was after the weaning of the kits. For MP12 and MP18 the frequency of different categories of aggressive interactions were significantly higher on the day of grouping than afterwards, with a strong decrease on day 6 (P < 0.02), but almost no change was found between days 6 and 10. This was especially true for biting, with a high frequency of occurrence just after grouping and a subsequent decrease on day 6 under all management schedules (P = 0.005). The change in the number of aggressive interactions between 6 and 10 days after grouping was not significantly different between MPs. However, the time point of 6 days after grouping seemed to be fundamental in reducing the number of aggressive events. Although a longer separation for 18 and 22 days after parturition did not reduce the total number of aggressive interactions, MP18 and MP22 showed more mild aggressive interactions with respect to MP12 on the day of regrouping. Moreover, when comparing MPs concerning the development of hierarchy, hierarchies appeared very stable independently of the length of grouping (P < 0.01).