Holmes, J., Waters, D., Maisonave, I. et al. 2017. Social interaction for non-sibling pregnant New Zealand white rabbits on reproductive toxicology. Animal Technology and Welfare 16(2), 139-141.

Rabbits are gregarious animals that live in social groups in the wild so individually housing our animals, while meeting the present scientific objectives, restricts their natural social behaviour. How to meet the social needs of our rabbits while maintaining a large (up to 600) experimental population was the challenge we looked to address. We considered using floor-pens for our rabbit reproductive studies but when considering the space requirements and the required flexibility in our animal room use we felt that this was not an option. The benefits or challenges of group exercise sessions for pregnant rabbits were previously unknown. Following discussions with our Home Office Inspector an exercise research and development study was conducted in order to trial this potential welfare initiative. It was agreed that one group of five pregnant females (identified as group 2) would be provided with group exercise sessions three times per week for 30 minute periods throughout the study from prior to mating (two occasions), then from day 1 after mating until termination on Day 29. A similarly constituted control group (identified as group 1) was maintained on study for the same duration however these females were not exposed to any group exercise sessions throughout the study. A variety of toys, tunnels, key rings and chains were provided as well as hay. Shelters were provided for the animals to retreat to if they desired. The animal room flooring was covered with absorbent paper to both aid traction and to keep the floor clean. There were no adverse effects from exercise on the clinical condition of the animals with the exception of one female that was observed with a broken claw immediately after exercise. Behaviours observed amongst females during exercise sessions comprised of interaction between the group mates including thumping hind legs, grooming each other, nuzzling, laying side-by-side and chasing around the pen. Aggression was observed on occasions between all females however this was primarily instigated by two females indicating potential dominance in these animals. Further behavioural observations during exercise comprised of interaction with toys, acrobatics/’binking’, scent marking and scratching; signs of which are generally associated with contentment or ‘happiness’. There was no adverse effect of exercise on the clinical condition of the females and bodyweight gain was enhanced in females subject to regular exercise when compared with control (non-exercised) females, despite consistently lower food intake amongst these animals. Reproductive performance was also enhanced in females exposed to regular exercise with significantly reduced implantation loss, correlating with marginally increased litter sizes and litter weights when compared with control females. It is therefore concluded, regular group exercise in pregnant New Zealand White Rabbits may be beneficial and is certainly not detrimental to the overall maternal bodyweight gain and embryo-fetal survival. However, due to the aggression seen during every exercise session, frequent intervention by the observers was required, greatly increasing the anticipated resource requirements. During the early stages of the study up to four technicians were required to ensure animals were not injured due to fighting.