Performance and feeding behaviour of group–housed rabbits with free or time–limited access to feed

The present study aimed at evaluating the effect of the feeding system (AL: ad libitum vs. R: time–based feed restriction) on performance, feeding behaviour and slaughter results in group–housed growing rabbits. A total of 288 crossbred rabbits of both sexes were housed in 18 pens (16 animals per pen), half fed ad libitum and half restricted during the first 3 weeks, and controlled from weaning to slaughter (33 to 75 d of age). At the beginning of the trial, R rabbits had access to feeder for 10 h a day; feeding time increased by 1 h every 3–4 d until 16 h/d in the first three weeks; then, feeding time increased by 1 h/d until 24–h access to feeders in the 4th week; thereafter, all animals were fed ad libitum. Rabbit feeding behaviour was controlled at 39, 46, 53 and 60 d of age by weighing the feeders every hour by an automatic weighing system. Individual data (live weight, carcass data) were analysed by PROC MIXED of SAS with the feeding system as fixed effect and the pen as a random effect; pen data (feed intake and conversion) were analysed by PROC GLM of SAS. During the whole trial, AL rabbits exhibited small and frequent meals during all the day with minimum intakes (about 2–3 g/h) in the morning (9:00 to 11:00 h) and maximum intakes (7–10 g/h) in the evening (19:00 to 21:00 h). R rabbits showed higher hourly feed consumption than AL rabbits, with peaks of 18, 15 and 14 g in the first hour after accessing feeder at 39, 46 and 53 d of age when the feeding time was 11, 13 and 16 h/d, respectively. Once fed freely, R rabbits took only two days to reach the same intake pattern of AL rabbits. In the first three weeks, feed intake was lower (–5%, i.e. 128 vs. 122 g/d; P<0.01) and feed conversion was better (–5%, i.e. 2.42 vs. 2.29; P<0.001) in R rabbits compared to AL ones. In the following 3 weeks, R rabbits showed a worse feed conversion than AL rabbits (+ 5%, i.e. 2.70 vs. 2.83; P<0.001). In the whole trial, the feeding system did not affect health status, growth performance, slaughter weight (on average 2860 g), dressing percentage (61.0%) and carcass and meat quality traits. In conclusion, feeding behaviour was heavily affected by the restriction program, but rabbits returned quickly to a normal behaviour once fed freely. The time–restriction program in the first three weeks reduced feed intake level at 95% of ad libitum without compromising growth performance and slaughter results.