Performance and sustainability of two alternative rabbit breeding systems
The aim of this study was to evaluate 2 alternative breeding systems that differ from the current system in terms of reproduction rhythm, age of females at first insemination and the age of kits at weaning and at slaughter. We measured the performance of 332 females and their offspring over 4 consecutive cycles, as well as the sustainability of the systems. We compared an intensive (group I: reproduction rhythm [RR]=35 d; first insemination [AI 1 =20.6 wk of age; weaning age [WA]=32 d; slaughter age [WS]=63 d) an extensive (group E: RR=49 d; AI 1 =16.6 wk; WA=30 d; WS=70 d) and a semi intensive system (group S: RR=42 d; AI 1 =19.6 wk; WA=35 d; WS=70 d) considered as the control system. Sustainability was evaluated using a multicriteria assessment method that takes 14 economic, environmental and social criteria into account, for which 3 to 5 indicators were expressed as the relative score 1; 0.5; 0; +0.5; +1] for alternative systems compared to the control system. The productivity measured at 28 d (3.5, 4.2 and 4.6 kg/AI, for groups I, S and E, respectively) at 63 d post partum (30, 38 and 42 kg/female for 4 cycles, respectively) and the total body energy measured 3 d after the 1st and at the 4th insemination (45.4, 46.8 and 49.5 MJ, respectively) were significantly increased when the reproductive rhythm decreased (P<0.001) Before and after weaning, kit mortality decreased when the reproduction rhythm decreased (11.4, 7.3, and 1.9% and 18.3, 15.3 and 10.6% for groups I, S and E, respectively, P<0.05) Carcass quality (weight and dressing percentage) was lower in I than in the S and E groups (P<0.001) On this basis, the yearly productivity per doe at weaning could be estimated at 79, 83, and 78 kg for groups I, S and E, respectively. Consequently, the productivity per reproductive cycle increases with the extensification of the breeding system. Nevertheless, compared with the current French system (S) simultaneous changes in several breeding practices could lead to new coherent and functional systems capable of improving various aspects of sustainability.