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Feeding, Nutrition and Rearing Systems of the Rabbit
Full text linkDuring the last years, several issues have contributed to a progressive decline in rabbit meat consumption in the European Union, including consumers’ concerns for animal welfare, the unsuitable presentation of the end product, an increased popularity of rabbits as pet animals, high production costs (aggravated by the ongoing geopolitical crises), and criticism about the environmental sustainability of rabbit farms [...
Time-based feed restriction and group size in growing rabbits: effects on health status and growth performance
Full text linkPerformance and feeding behaviour of group–housed rabbits with free or time–limited access to feed
No full textThe 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
Effects of time-based feed restriction on morbidity, mortality, performance and meat quality of growing rabbits housed in collective systems
Full text linkIn rabbit farms, quantitative feed restriction in the post-weaning period is widely used with the aim of reducing the impact of digestive diseases, whereas less information is available about feed restriction strategies based on the reduction of access time to feeders in different housing systems. This study compared morbidity, mortality, growth performance, carcass characteristics and meat quality of 368 crossbred rabbits fed ad libitum (L) or subjected to a time-based feed restriction programme (R) and housed from 31 to 73 days of age in cages or pens with different dimensions and group sizes, that is, eight conventional cages (0.33 m2, six rabbits/cage), eight small open-top pens (0.50 m2, eight rabbits/pen), eight medium open-top pens (1.00 m2, 16 rabbits/pen) and four large open-top pens (2.00 m2, 32 rabbits/pen). Feed restriction was attained by progressively reducing the access time to feeders in the 1st week from 14 to 8 h/day, maintaining 8 h in the 2nd week and then by increasing access time by 1 h/day during the 3rd and 4th week up to 24 h/day. In the first 2 weeks, R rabbits showed a lower (P≤0.001) daily weight gain, feed intake and feed conversion as compared with L rabbits. During the 3rd and 4th weeks, R rabbits exhibited a greater daily weight gain and better feed conversion (P≤0.001). In the last 2 weeks of trial, daily weight gain tended (P=0.06) to be greater in the R than L rabbits. In the whole trial, R rabbits manifested a lower daily weight gain, feed intake and feed conversion, as well as lower final live weight and the carcass dressing percentage at slaughter (0.05≤P≤0.01). During feed restriction, R rabbits did not show digestive problems, which, however, appeared in the following 2 weeks of refeeding. Thus, R rabbits had a higher health risk index in the whole trial as compared with L rabbits (P≤0.05). The housing system did not affect growth performance, characteristics at slaughter, and carcass and meat quality. Mortality tended to increase with group size (P=0.06). In conclusion, the time-based feed restriction significantly improved feed efficiency of growing rabbits housed collectively but had somewhat negative effects on characteristics at slaughter and on morbidity and mortality rate
Time-based restriction and refeeding programmes in growing rabbits: Effects on feeding behaviour, feed efficiency, nutrient digestibility, and caecal fermentative activity
Full text linkThe present study evaluated the effect of five feeding programmes (AL, ad libitum feeding; DF, daylight access to feed followed by fast full refeeding; NF, nightly access to feed and fast full refeeding; NS, nightly access to feed and slow full refeeding; NI, night access to feed until the end of the trial) on growth, nutrient digestibility, caecal fermentative activity, and carcass and meat quality of 400 crossbred rabbits housed in 40 open-top pens (10 rabbits/pen) from weaning to slaughter (28–70 days of age). In all feed-restricted rabbits, feeding time decreased from 14 to 9 h/day during the 1st week, it stood at 8 h/day during the 2nd week, and it increased from the beginning of the 3rd week according to three refeeding systems: i) fast until ad libitum (+4 h/day until 24 h/day) for the DF and NF groups; ii) slow until ad libitum (+1 h/day until 24 h/day) for the NS group; and iii) very slow and until 12-h-restriction (+30 min/day until 12 h/day) for the NI group. During the restriction period, DF and NF programmes compared with the AL programme, improved the coefficient of total tract apparent digestibility (CTTAD) for crude protein (+4.6%) and ether extract (+2.7%) (P < 0.001); NF programmes increased caecal volatile fatty acids (VFA) (79.7 vs 67.7 mmol/L; P = 0.034) and decreased pH (5.32 vs 5.46; P = 0.013) compared with AL. During the refeeding period, the NI programme increased the CTTAD of dry matter (+2.9%; P = 0.001), crude protein (+3.9%; P = 0.003), and gross energy (+2.6%; P = 0.001) compared with the DF and NF groups. The AL, DF, and NF treatments decreased caecal VFA compared with NS and NI (81.0 mmol/L vs. 95.4 mmol/L; P < 0.001). In the whole trial, the NI programme decreased feed intake (−7.5%; P < 0.001) and feed conversion (−6.7%; P = 0.002) compared with the AL programme, without differences in growth, final live weight, and slaughter traits among groups. Compared to AL feeding, feed restriction increased the mortality rate due to digestive disorders (9.0 vs 1.6%; P = 0.036), without affecting morbidity and health risk index. Slaughter weight (on average: 2608 g), carcass yield (60.2 g/100 g live weight at slaughter), and carcass and meat quality traits were not affected. In conclusion, the NI programme improved feed efficiency without impairing growth, slaughter, and carcass traits
Characterization study of aggressive behaviours in group-housed rabbit does
No full textA total of 32 crossbred multiparous pregnant rabbit does were housed in individual modules (0.5 m2) which were put in communication to form 8 double and 4 quadruple pens and to house 2 and 4 does, respectively. The females were maintained in stable groups from the starting of the trial (8 d before kindling) until 2 d before kindling and from the 18th day of lactation until weaning (31th day). The aggressive interactions among does were controlled by video-recording for 24 consecutive hours during the initial group formation at 8 d before kindling (−8 d), during the re-introduction in the groups at 18 d of lactation (+18 d) and at 21 and 30 d of lactation. At −8 d and +18 d group formations, the most observed aggressions were biting and attacking, followed by threatening, boxing and carousel fights, and finally chasing. There was a higher number of biting, threatening and total aggressions at −8 d than at +18 d (P<0.05). The effect of the observation hour was significant for all types of aggressive interactions (P<0.05) at both observation days, although with a different pattern for each day: at −8 d aggressions took place essentially during the first two hours after the group formation and thereafter they were reduced; at +18 d, the aggressions were concentrated on the first 30 minutes after the group formationand thereafter they were rather null. At 21 and 30 d of lactation, few and null aggressive interactions were observed, respectively. In conclusions, more aggressions and, likely, longer periods for establishing hierarchy were observed on the first group formation and with does close to the kindling, while lower aggressions and shorter periods for stabilisation were measured at the re-introduction in group and at the end of the lactation period
Effect of feed restriction programs and slaughter age on digestive efficiency, growth performance and body composition of growing rabbits
No full textThe effects of the feeding system (ad libitum vs. restricted) and the restriction programs (daily vs. weekly base) were evaluated on 300 commercial crossbred rabbits housed individually from weaning (37 d) until slaughter (at 73 d and 80 d of age). During the first three weeks, restricted rabbits received from 85% to 100% of the ad libitum intake according to two feeding curves with daily (+4 g/d; D group) or weekly increments (+22 g/week on average; W group). In the restriction period, the feeding system affected CTTAD of crude protein (+2.4% in restricted compared ad libitum rabbits; P < 0.01). After restriction, dry matter (P = 0.10), ether extract (P = 0.03) and ADF (P = 0.05) CTTAD were lower in previously restricted rabbits compared to those always fed ad libitum. During the first period, feed restriction reduced daily weight gain (−7.5%; P < 0.01), feed intake (−7.1%; P < 0.001), empty body lipid (−12.7%; P = 0.03) and energy (−5.2%; P < 0.01) contents compared to ad libitum feeding. In the second period, previously restricted rabbits showed higher daily weight gain (+8.7%; P = 0.02), lower feed conversion (-6.0%; P = 0.03), besides higher empty body lipid (+16.0%; P < 0.01) and energy (+6.6%; P < 0.01) contents compared to rabbits fed ad libitum. In the whole trial, feed restriction reduced mortality (20.7% vs. 8.7%; P < 0.01) and tended (P < 0.10) to reduce feed intake (142 vs. 139 g/d), feed conversion (3.10 vs. 3.05) as well as N retention (53.6 g vs. 51.9 g). The restriction program had no effects during the restriction period. In the re-feeding period, rabbits submitted to the week–by–week restriction exhibited higher weight gain (P < 0.01) and feed intake (P = 0.02) and lower feed conversion (P = 0.01) compared to those restricted on a daily base. In the whole trial, W rabbits showed higher feed consumption (P = 0.04) and N excretion (P = 0.05) than D rabbits. A later slaughter age increased final live weight (+8%; P < 0.001) and feed conversion (+11%; P < 0.001), dressing out percentages, dissectible fat, and hind leg muscle to bone ratio, empty body lipid (+13%; P = 0.02) and energy contents (+4.2%; P = 0.03), besides body N retention (+11%) and excretion (+32%) (P < 0.001). In conclusion, regardless from the restriction program, a mild feed restriction (93% of ad libitum) during the first period improved rabbit health status and reduced environmental pollution in the fattening sector without impairing growth performance, slaughter results and carcass traits
Time-based feed restriction and group composition in growing rabbits: Effects on feed intake pattern, growth performance, carcass traits and meat quality
No full textThis study aimed to evaluate the effects of the feeding system (AL: ad libitum, R: feed restriction) and group composition (X: only females, Y: only males, XY: mixed sex) on the feed intake pattern, growth, and slaughter results in growing rabbits. A total of 288 crossbred rabbits were housed in 18 pens (16 animals per pen) from weaning to slaughter (33 to 75 d of age). At the beginning of the trial, R rabbits had access to the feeders for 10 h/d, afterwards, feeding time increased by 1 h every 3-4 d in the first three weeks until 16 h/d was reached, and by 1 h per day until 24-h access to feeders was reached in the 4th week; thereafter, all animals were fed ad libitum. On average, the feed intake pattern of AL rabbits was characterized by small and frequent meals throughout the day, with minimum intakes (about 2-3 g/h) occurring in the morning and maximum intakes (7-10 g/h) in the evening. During the restriction period, R rabbits showed a lower daily feed intake (-6 g/d; P < 0.01), better feed conversion (2.29 vs. 2.42; P < 0.001), and a higher hourly feed intake compared to the AL rabbits, reaching peaks of 18, 15, and 14 g/h when the feeding time was 11, 13, and 16 h/d, respectively (P < 0.001). In the second period, once the rabbits were fed freely, R rabbits achieved the same intake as AL rabbits but with a higher feed conversion (4.10 vs. 3.89; P < 0.001). In this study, the feeding system did not affect growth performance, health (mortality 1.4% on average), carcass traits, and meat quality. In terms of group composition, the daily growth and feed conversion were worse in the Y groups than in the X and XY groups in the second period (P ≤ 0.01), with no other differences observed throughout the whole trial. Dressing out percentage was significantly different among the three groups (61.8%, 61.0% and 60.2% in group Y, group XY and group X, respectively; P < 0.001). In conclusion, time-based feed restriction during the first three weeks (based on an access to the feeders increasing from 10 h/d at the beginning until 16 h/d) reduced the feed intake to 95% of ad libitum, without compromising growth performance and slaughter results, but modified the rabbit feed intake pattern during the restriction phase. In terms of gender composition, the separate housing of male and female rabbits was not justified by our results
Effect of Genotype, Gender, and Feed Restriction on Slaughter Results and Meat Quality of Broiler Chickens
Full text linkSlaughter results and meat quality were evaluated in 768 broilers according to genotype (standard breast yield vs. high breast yield), gender, and feeding systems
(ad libitum vs. feed restriction from 13 to 21 d of age). Standard-yield chickens had higher carcass weights (2358 g vs. 2319 g; P < 0.001) and hind legs proportion (31.1%
vs. 30.6%; P < 0.01), and lower dressing out percentage (73.6% vs. 74.0%; P < 0.01) compared to high-yield birds, besides lower meat L* index (45.3 vs. 46.2; P < 0.05),
higher final pH (5.89 vs. 5.85; P < 0.05) and thawing losses (10.5% vs. 9.43%; P < 0.05). Males showed higher carcass weight (+24%), dressing percentage (+0.7%), and hind leg yield (+4%) (P < 0.001) than females. Restricted birds had lower carcass weight (–2%; P < 0.001) and dressing percentage (-0.3%) (P < 0.05) than those always fed ad libitum. As what concerns meat quality, gender and feeding system aff ected only meat final pH, lower in ad libitum group than in restricted one and in females than males. In conclusions, slaughter results and carcass traits changed especially with genotype and gender, coherently with slaughter weight whereas meat quality was mostly
affected by genotype
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