Behaviour and welfare assessment of autochthonous slow-growing rabbits: The role of housing systems

Understanding the farming system impact on animals is crucial for evaluating welfare. Rabbits exhibit distinct behaviours influenced by their surroundings. The conditions in which they are raised directly influence behaviour and stress responses, emphasizing the importance of providing an optimal environment for their overall well-being and growth. In this study, we assessed the behaviour and welfare of two Italian local rabbit populations, namely the grey rabbit of Carmagnola and the grey rabbit of Monferrato. These rabbits are not yet officially recognized as breeds, but they are commonly used in Italy for meat production and represent a distinctive phenotype and local heritage among farmers and consumers. We analysed the behavioural patterns, physiological responses, and blood parameters of the animals to assess the influence of both age and three distinct housing systems (traditional single cages, group farming, and a mixed system) on rabbits' welfare. In this study, 294 weaned males with 35 days old were divided into three housing systems with seven replicates each until reaching slaughtering age (100 days of age). A traditional single cage system, a group farming with 10 animals each replicate and a Mixed pilot system with 10 rabbits initially grouped, then transferred to single cages. The findings from the behavioural analysis and the evaluation of salivary and hair corticosterone levels demonstrate that both the housing system and the age of the rabbits exerted significant effects on their welfare. Rabbits in group housing displayed a wider range of behavioural patterns, including increased kinetic activities such as running, walking, and exploration. However, this housing system was associated with higher levels of both salivary and hair corticosterone, indicating a high acute and chronic stress condition. The single cage system was associated with higher levels of acute stress and a low frequency of kinetic activities and social interactions, with a predominant behaviour of turning on themselves. The age factor significantly influenced the occurrence of behaviours, with younger rabbits exhibiting higher levels of kinetic activities, while social behaviours such as attacks and dominance were more prevalent as the rabbits reached sexual maturity (around 80-85 days of age). Moreover, the attainment of sexual maturity coincided with an increase in salivary corticosterone levels. We found a significant association between attack behaviours, escape attempts, and elevated corticosterone levels, by demonstrating that these behaviours can be used as indicators of decreased animals' well-being. Our findings underscore the importance of considering both the housing environment and the temporal dimension in the study of behaviour and welfare. This enables a comprehensive assessment of appropriate rearing management techniques. By understanding the social dynamics and stress sources within housing systems, farmers can implement measures to enhance animal welfare and create a conducive environment for the health and behaviour of rabbits.

Cage enrichment to minimize aggression in part-time group-housed female breeding rabbits

In most rabbit farms, breeding does kindle and nurse their kits in single-litter cages throughout their entire reproduction cycle. However, the protective behavior can lead to aggressive displays and injuries when the does are housed in groups. This study aimed to evaluate cage enrichment for reducing the agonistic behavior in part-time group-housed does. A total of eighty does with their 22-day-old kits were allocated to 20 multi-litter cages, with each cage housing four does and their litters for 10 days. Each multi-litter group was subjected to one of four treatments: alfalfa blocks as distraction material (A), wooden panels underneath the platforms (P), both alfalfa and wooden panels (AP), or no extra enrichment (controls, C). This experiment was replicated for three consecutive reproduction cycles. The skin injuries of the does and the kits were scored with a tagged visual analog scale before grouping and at one, three, six, eight, and 10 days after grouping. Computer vision techniques were used to continuously monitor rabbit activity and agonistic behavior (aggression and fleeing/chasing) during the first 24 h after grouping, specifically during light hours. During the first day in the group, 67.2% of the does and 13.4% of the kits acquired new injuries. This increased to 82.0 and 33.2%, respectively after 10 days in the group relative to the onset of grouping. The injury scores of the does increased toward the sixth day after grouping compared to the first (p < 0.001) and were highest on the tenth day for the kits (p < 0.001). On all the observation days, the number of injured does was higher in C compared to A (p = 0.04) and AP treatment (p = 0.005). There were no other treatment effects observed on the doe or kit skin injuries. Rabbit activity was highest after grouping but decreased after the first and second days (p < 0.001). The agonistic interactions between the does involved more fleeing/chasing behavior (62.0%) rather than aggression (38.0%). Although hierarchy fights are likely when unacquainted does are group-housed, the many animals that sustained injuries and the high injury scores confirm that part-time group housing for does is challenging and possibly inevitable. This study has shown that alfalfa, with or without wooden panels, can slightly reduce the number of injured does.

Effect of group size and escape enrichment on reproductive performance of breeding does in part-time group housing

Societal demands for group housing of social farm animals such as rabbits are increasing due to animal welfare concerns. When breeding does are housed in groups, maternal protective behaviour negatively affects the reproductive performance of the does. In part-time group housing, does are housed in single-litter cages starting shortly before parturition until the first part of lactation and then group housed for the second part after their protective behaviour has diminished and the kits are more resilient. The aim of this study was to evaluate the reproductive performance of breeding does in a part-time group housing system with provision of escape enrichment and different group size (and concomitant different stocking density, as pen size remained unchanged). For each of the four consecutive reproductive cycles, 42 does with their kits switched at 22 d post-partum (pp) from single-litter to group housing for a total period of 13 d in pens of 200×102 cm by removing walls between four adjacent single-litter cages. Newly created group pens (N =12 pens per treatment) varied in group size, stocking density and enrichment: groups of either three or four does were divided over same-size pens with or without escape enrichment (2×2 factorial design). The escape enrichment was comprised of two sets of PVC pipes and two extra elevated platforms. Does were weighed and kits counted at parturition, after which kits were cross-fostered. Kits were counted and weighed again 22 and 35 d pp. Results for mean doe fertility (90.0%), number of kits (9.1 kits/litter) and kit weight (1037.3 g/kit) at weaning were comparable with professional farms using single-litter cages. No significant effects of group size and escape enrichment were found for any of the reproductive parameters. While housed in group, seven does were removed from the experiment, from which four does were severely injured. Post-grouping kit mortality was rather low (6.7%), but three kits were euthanised due to severe injuries. In conclusion, provision of escape enrichment and altered group size (and stocking density) had no profound effect on the reproductive performance of part-time group housed does.

Grouping of breeding rabbit does at different time points: effects on fertility, mortality and weight

<p>Semi-group housing in breeding does has been shown to reduce production and breeding success in comparison to single-housed animals. One reason for this reduction could be stress and aggression when grouping does only 2 d after artificial insemination. The aim of this study was to test different time points of grouping on fertility of does, body weight of both kits and does, and mortality rates. Hence, does were separated and housed individually one day before giving birth to their kits. The does were then artificially inseminated on day 10 postpartum (dpp) and regrouped according to the treatment (time point) on 12 (TG12), 18 (TG18), or 22 (TG22) dpp, respectively. In total, five trials with three groups pertaining to the three treatments (eight does per treatment group) were conducted. Non-pregnant does were replaced with pregnant does before each new trial (57 different does needed). Data were analysed with (generalised) linear mixed effect models and survival analysis. There were no significant differences in fertility, body weight<br />or mortality of does among the treatments. The average fertility rate (number of kindling events/number of artificial inseminations×100) was low (40.92%) and seasonal effects may have partially masked treatment effects, as most trials took place during winter. Likewise, the survival rate of kits was not influenced by the treatment (survival test: χ²=2.3, df = 2, <em>P</em> = 0.3). Body weight of the kits was also not affected by the time point of grouping (average weight: 447.70±46.42 g (TG12), 452.20±55.30 g (TG18) and 460.06±89.23 g (TG22); <em>P</em> = 0.33). In conclusion, grouping does at a later time point in the reproductive cycle did not show any significant improvement in the breeding or productive success in a Swiss semi-group housing system. An elongated separation from conspecifics did not enhance the welfare of semi-group housed rabbits.</p>