Effects of temporary nest box removal on maternal behaviour and pup survival in caged rabbits (Oryctolagus cuniculus)

Free nest access is widely used in the management of commercial breeding units for fattening rabbits, but potentially counteracts the doe's behavioural goal of a closed nest entrance, leading to repeated nest visits without nursing and attempts to close the entrance due to an overtaxed adaptability. Due to injuries, crushing and hypothermia caused by such behavioural problems, pup mortality can be more than 20% under these circumstances. To study the effect of nest access on doe's nest related behaviour, pup mortality and pup weight, three groups of 10 does each had either free access ('F'), controlled access with the entrance closed with a sliding door ('S') or controlled access with the nest box removed outside nursing time ('R'). In groups with controlled access, nursing was admitted for 15 min each morning from day 1 to 15. Behavioural data were achieved from does rearing a second litter (7 does per group) and included the general activity and the frequency, intensity and temporal distribution of nest approaches, including investigations of the nest entrance ('entrance checks') or of the nest and pups ('nest checks') and nesting activities (nest opening and closing behaviour). Data on pup mortality, causes of death and pup weights were gained from 62 litters over three consecutive reproductive cycles. Over 24 h, group F showed significantly more short nest approaches than group R, whereas group S performed significantly more medium length approaches than group R and more long approaches than R and F. In the hour after nursing and outside nursing hours, group F showed significantly more nest checks than S and R. Group S performed significantly more entrance checks in the hour after nursing, more nesting activities before and outside nursing and the highest general activity. Outside nursing hours, group R showed the lowest frequency of nest approaches and nesting activities. Nesting activities were distributed over almost all 24 h a day in groups F and S, whereas they were more restricted to nursing time in group R. Pup mortality and weaning weights did not differ significantly between groups.