A multifactorial evaluation of different reproductive rhythms and housing systems for improving welfare in rabbit does

The most widespread reproductive rhythm practiced in rabbit farming is based on artificial insemination (AI) performed at around 11 days pospartum. This approach results in high production rates, but requires high yearly replacement of animals that cannot sustain the enormous energy demand. Rabbit does that are in energy deficit have relatively short reproductive careers. Moreover, current housing systems do not allow animals to express the typical behavioural pattern of the species, with presence of abnormal behaviours that contribute to reduce welfare. Thus, the present study aimed to evaluate the best combination of housing systems and reproductive rhythms through multiple indicators (performance, behaviour, corticosterone assessments) to improve does' welfare. A total of 110 nulliparous rabbit does of the Grimaud hybrid maternal line were randomly allocated to 2 different housing systems, an innovative type of cage, Combi cage (C), vs. the conventional cage currently used in intensive farming, Standard cage (S), within which 3 reproductive rhythms: Intensive (I), with AI 11 days postpartum; Alternating (A), with AI alternated between 11 and 30 days postpartum; or Extensive (E), with AI 30 days postpartum, were applied. All rabbits underwent 6 consecutive reproductive cycles, according to a multifactorial balanced experimental plan (2 x 3), as follows: CI (20 does) vs. CA (20 does) vs. CE (20 does) vs. SI (5 does) vs. SA (5 does) vs. SE (5 does). At the main critical phases (AI, kindling, and peak lactation), we conducted reproductive, behavioural, and hormone assessments (salivary corticosterone). CE group showed higher motor activity, lower feeding rates, and increases in number of live kits and weaned kits, which resulted in better reproductive performance in the C cages. The SA group displayed the highest number of live-born kits/litter (P < 0.02), the highest total weight of the weaned litter (P < 0.01), and the lowest pre-weaning mortality (P < 0.04) among S cages. The housing system also influenced behaviour: S does displayed the highest frequencies of self-grooming (P < 0.01), feeding (P < 0.001), and stereotypical behaviours (sniffing and biting bars, P < 0.01), which indicated frustration from a lack of stimuli and consequent boredom. Based on our results, we concluded that AI after kit weaning (E) was the best reproductive rhythm for does in C cages, and the A rhythm was best for does in S cages. However, from an ethological point of view, in the S cages, stereotypes related to the small size of the housing system still remain.