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The effects of a (30 cm high) elevated platform as an enrichment structure on the behaviour and performance of fattening rabbits kept in groups were investigated. Three housing systems for fattening rabbits were compared using a stocking density of 15 rabbits m–2. The rabbits were housed either in large pens (3.67 m2plus a platform of 0.39 m2; with 60 rabbits per pen) or in small pens (0.503 m2plus a platform of 0.159 m2; with10 rabbits per pen), or in conventional standard cages (0.39 m2, with 6 rabbits and without any enrichment) from 31 to 72 days of age. The conventional cages without a platform were used as a control and reference model. Rabbits housed in each small pen or in each cage belonged to the same litter, and the 60 rabbits sharing the same large pen were from six or seven litters. At the end of fattening, rabbits reached the weight of 2,508 g in cages, 2,397 g in small pens, and 2,340 g in large pens; the only significant difference was daily weight gain which was better in cages than in both pens. There was no difference in growth parameters between the two types of pens. The mortality rate was less than 1% for all treatments. No sanitation problems or severe lesions were seen with rabbits even those reared in large pens and large groups. Neither housing systems, nor elevated platform affected activities such as dietary intake or resting. The use of the platform appears to depend upon the amount of space available; in a large pen, an elevated platform can be utilised as an exercise structure while in a small pen it was used more as simply extra space to occupy.

Three housing systems for fattening rabbits were compared using a stocking density of 15 rabbits m–2. The rabbits were housed in large pens (3.67 m2, 50 rabbits), small pens (0.66 m2, 10 rabbits) or in conventional standard cages (0.39 m2, 6 rabbits) from 31 to 72 days of age. Rabbits housed in each small pen or in each cage belonged to the same litter, and the 50 rabbits housed in each large pen were from six or seven litters. At the end of fattening, when rabbits were 72 days old, there was no significant difference in the weight of rabbits from the three different housing systems, even though the rabbits from small pens were slightly heavier in weight compared with rabbits from large pens. The best feed conversion ratio was found in rabbits from cages, but was only significantly different from rabbits housed in small pens. No significant differences were found in the main activities: nutrition, social behaviour, resting, and standing; however, the frequency of runs, hops and consecutive hops was significantly higher in rabbits from large pens compared with rabbits from the two other housing systems. These results confirm that the total surface area available for animals is the most important factor for such locomotory activities. This study did not reveal any significant difference in aggressive behaviours between rabbits from different litters housed in large pens and between rabbits from the same litter housed in small pens or cages.

The possibility of improving the welfare of fattening rabbits by rearing them in pens instead of cages was investigated. Time budgets, locomotion, ear lesions, breaking strength of the femur and productivity were compared in fattening rabbits kept at the same stocking density (15 rabbits m−2) either in standard cages of 0.4m2(6 animals) or in pens of 1.6m2(24 animals). Behavioural observations, performed by video recording at 6 and 9 weeks of age, indicated that the frequency of rabbits walking over one another was higher in cages than in pens at 9 weeks of age. Although the time spent in locomotion did not differ significantly, the number of consecutive hops performed by animals was clearly increased in pens at 6 weeks and tended to be higher at 9 weeks. In pens (without a ceiling), rabbits were observed ‘keeping watch’ with a characteristic fully upright posture; this was not possible for rabbits in cages (with ceilings at 30cm).Ear lesions were more frequent in caged rabbits than in penned; this might be due to the caged rabbits walking on one another, due to the lack of space to perform locomotory behaviour. Weight, diameter and breaking strength of femur tended to increase in rabbits kept in pens. In penned rabbits, body and carcase weight were significantly reduced (by 2.0% and 3.4% respectively) when compared with caged ones. However, overall, the use of wire-floor pens of 1.6m2, housing 24 animals, was considered to be beneficial to fattening rabbits’ welfare when compared to standard-sized cages holding 6 animals.

1. Perching behaviour of Ross broiler chickens was studied in order to increase the available space at the floor level. Pens (36 m2) were equipped with wooden perches mounted 20 and 33 cm above the litter (5 cm perch length per bird). 2. The influences of stocking density (22 vs 11 birds/m2, experiment 1) and of a 10 min artificial dusk (17 birds/m2, experiment 2) were tested in a 2x2 factorial design (n=4 by treatment) including control pens without perches. In experiment 3, perching behaviour between 2 different group sizes (1020 vs 4590 birds, 17 birds/m2, no replicates) was compared. 3. The percentage of perching birds (PPB) was assessed by scan sampling observations during the 20 to 22 h light period (8 observations per d, 5 d a week, from week 3). In experiment 2, infra-red video recording was performed at the time lights were dimmed and during the dark period. In experiment 1, carcase lesions were noted. In experiment 2, tibia breaking strength of frequently perching birds was compared with controls. Birds were weighed before slaughter and food conversion was calculated. 4. PPB increased with age and density (P0.01) and was highest at the 22 birds/m2 density during week 6 (mean=10.6%, maximum=13.5%). PPB was not influenced by a 10-min artificial dusk. In experiment 3, PPB was slightly lower during weeks 5 and 6 in the large group size compared to the small group size (6.8% vs 7.9% respectively in week 6). 5. Prevalence of carcase lesions and tibia breaking strengths were unrelated to perch usage. Final body-weights were not influenced by the presence of perches except at the 22 birds/m2 density where males were slightly heavier in the control pens compared with males in pens equipped with perches (2096 g vs 2051 g, P=0.015). Food conversion was independent of the presence of perches.

1. The effect of stocking density on welfare traits of turkeys was studied in 2 experiments. In each experiment 2,633 sexed BUT turkey poults were assigned to 3 rooms, 135 m2 with 1 treatment per room. Because of the large flock size (675,878 and 1080 birds in T1, T2 and T3 respectively) treatments were not replicated 2. Floor space allowances varied according to treatment; for the males: 24 dm2, 18.5 dm2 and 15 dm2 until week 12 and 40 dm2, 31 dm2 and 25 dm2 from week 12; for the females: 16 dm2, 12.3 dm2 and 10 dm2. 2. The scan sampling method in experiment 1 and the focal sampling method in experiment 2 were used to record behaviour at week 6, 9, 12 (males and females), and 16 (males). Birds' ethogram was divided into 7 mutually exclusive behaviours: standing/walking, resting, feeding, drinking, pecking at the environment, pecking at another bird, and preening. Position changes in the pen and the frequency of disturbances of resting birds by other birds were recorded in experiment 2. 3. Gait was assessed at week 12 (females) and week 16 (males). Prevalence of lesions, breast (males), hip and foot (males and females), were recorded at slaughter. Birds were weighed at week 12 (males and females) and week 16 (males). 4. Stocking density had little influence on behaviour except on the frequency of disturbances of resting birds by other birds, which tended to be more frequent at the highest density. 5. Gait deteriorated as stocking density increased. Hip and foot lesions were more frequent at the highest density. Bodyweight decreased significantly with decreasing floor space. 6. The results suggest that turkey welfare was poorer at the highest density than at the 2 lower stocking densities.

The main aim of the study was to determine to what extent young rabbits kept on wire-floor cages would be attracted by straw bedding and how would access to straw modify their behaviour, health and performance. A total of 384 hybrid commercial breed rabbits (Hycol®) were assigned to 16 pens of 1.6 m2 (15 rabbits/m2). Eight pens used as controls had an all-wire floor, while in eight other pens, rabbits could choose between a wire floor or a deep litter topped up once a week and completely replaced once during the course of the 40-day-long study. Behaviour was recorded by video camera between 7 and 10 weeks of age through 24 h observations consisting of 24 sequences of 1 min every 60 min. Reactions to a new environment were compared between both treatments through the use of an open-field test. Parasitism was monitored from faeces and growth performance analysed. Time budgets showed resting, 60%; grooming, 19%; and feeding, 19–20%; were poorly influenced either at 7 or 10 weeks of age by type of floor. The most unexpected result was the low attraction of straw. Rabbits in the littered pens spent most of their time on the wire (89% at 7 weeks and 77% at 10 weeks; P

In order to evaluate genetic variation between rabbit haemorrhagic disease virus (RHDV) isolates and to derive phylogenetic relationships, 56 virus isolates collected from various parts of France over a 7 year period (1988 to 1995) were examined. Analyses were carried out by direct nucleotide sequencing of PCR fragments of three genomic regions encoding the capsid protein (VP60) (regions A and B) and a non-structural protein (region C). Multiple sequence alignments revealed maximum nucleotide divergence of 7.6, 9.4 and 8.7% for regions A, B and C, respectively, indicating a high level of conservation between isolates. Irrespective of the genomic region analysed, phylogenetic analyses carried out using various methods allowed the identification of three genogroups; distribution of isolates within these genogroups appears to be more related to the year of their collection than to their geographical origin. The possible evolution of RHDV is discussed.

In less than ten years, two very serious viral hepatic diseases have spread through Leporidae populations (rabbits and hares) in numerous countries. In May 1989, the Office International des Epizooties designated this new disease of rabbits "viral haemorrhagic disease" and entered it as a List B disease in the International Animal Health Code. Clinically, the disease is very similar to the European brown hare syndrome. However, numerous uncertainties prevail today on the true nature of the viruses of the two species. Although they are related, the viruses appear to be different and cross infection between species has given contradictory results. Hepatitis of Leporidae have probably existed in Europe for several years, although their viral aetiology has been demonstrated only recently. The acute form has occurred in hares in Northern Europe since approximately 1980, while the inapparent (or ignored) form has been present in rabbits in Czechoslovakia since 1975. These diseases of Leporidae are true viral hepatitis which, in their fulminating forms, bear a remarkable resemblance to human viral hepatitis (B and non-A non-B) with regard to clinical symptoms, pathological lesions and mode of transmission. The dominant faecal-oral transmission observed for types A and E hepatitis would explain the particular susceptibility of family-kept rabbits, as they are fed potentially contaminated fodder. As the clinically similar fulminating hepatitis in human beings is caused by a diversity of viruses (both RNA and DNA), the disease in Leporidae might also be caused by different viruses.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective cohort study was conducted in the Brittany region to identify the risk factors related to foot-pad dermatitis (considered an indicator of animal well-being) in chicken and turkey broilers reared under commercial conditions. Factors related to the shed, equipment, litter management and stocking density were recorded; the dependent variable was the prevalence of lesions observed on the slaughterhouse chain. Lesions were scored from 0 (no lesion) to 3 (severe lesion). Our survey lasted from May 1999 to October 2000. Fifty flocks of chicken broilers (15 farms), 27 flocks of female turkey broilers (21 farms) and 41 flocks of male turkey broilers (27 farms) were surveyed. In chicken broilers, 10% of flocks were of high quality (80% of birds with score 0) and this was related to the use of concrete floors with a thin layer of wood shavings. In turkey broilers, 48% of female and 46% of male flocks were of bad quality (>10% of birds with score 3). A poor fan ventilation system ( 3 /h/kg) was a significant risk factor. Turkey flocks of high quality were not observed. Stocking density had no influence on the prevalence of foot-pad dermatitis. We concluded that it is possible under high commercial stocking densities to have flocks with a low prevalence of foot-pad dermatitis in chicken broilers, whereas it is not in turkey broilers. Hence in chicken broilers, implementing a monitoring system based on the observation of foot-pad dermatitis prevalence at slaughter appears to be more appropriate than to legislate stocking density. In turkey broilers, it would probably be necessary either to reduce the stocking density drastically or to investigate new systems of floor drainage.

Two myxoma virus-rabbit hemorrhagic disease virus (RHDV) recombinant viruses were constructed with the SG33 strain of myxoma virus to protect rabbits against myxomatosis and rabbit viral hemorrhagic disease. These recombinant viruses expressed the RHDV capsid protein (VP60). The recombinant protein, which is 60 kDa in size, was antigenic, as revealed by its reaction in immunoprecipitation with antibodies raised against RHDV. Both recombinant viruses induced high levels of RHDV- and myxoma virus-specific antibodies in rabbits after immunization. Inoculations by the intradermal route protected animals against virulent RHDV and myxoma virus challenges.

In order to protect domestic and wild rabbits against RVHD, we constructed a recombinant vaccinia-RHDV virus, using the Copenhagen strain of the vaccinia virus. This recombinant virus expressed the RHDV capsid protein (VP60). Analysis of the expressed product showed that the recombinant protein, which is 60 kDa in size, was antigenic as revealed by its reactions in immunoprecipitation and indirect immunofluorescence with the antibodies raised against RHDV. The recombinant virus induced high level of RHDV specific antibodies in rabbits following immunization. Inoculations by both the intradermal and oral routes allow protection of animals against a challenge with virulent RHDV.

The causative agent of rabbit viral haemorrhagic disease (VHD) was purified by CsCl density gradient centrifugation from liver homogenates of rabbits infected with a strain of VHD virus isolated in France. Electron microscopy observations revealed that the virions were icosahedral with a diameter of 33-35 nm, and with an average buoyant density of 1.33. Structural proteins were investigated by SDS-polyacrylamide gel electrophoresis and western blotting. The results indicated the presence of a major structural protein of 64 kDa and other minor proteins of molecular weight of 43, 36 and 32 kDa, the last presumably resulting from the proteolytic degradation of VP 64. These results correspond with the description made by the different authors who identify the VHD virus as a member of the Caliciviridae family.

In less than ten years, two very serious viral hepatic diseases have spread through Leporidae populations (rabbits and hares) in numerous countries. In May 1989, the Office International des Epizooties designated this new disease of rabbits "viral haemorrhagic disease" and entered it as a List B disease in the International Animal Health Code. Clinically, the disease is very similar to the European brown hare syndrome. However, numerous uncertainties prevail today on the true nature of the viruses of the two species. Although they are related, the viruses appear to be different and cross infection between species has given contradictory results. Hepatitis of Leporidae have probably existed in Europe for several years, although their viral aetiology has been demonstrated only recently. The acute form has occurred in hares in Northern Europe since approximately 1980, while the inapparent (or ignored) form has been present in rabbits in Czechoslovakia since 1975. These diseases of Leporidae are true viral hepatitis which, in their fulminating forms, bear a remarkable resemblance to human viral hepatitis (B and non-A non-B) with regard to clinical symptoms, pathological lesions and mode of transmission. The dominant faecal-oral transmission observed for types A and E hepatitis would explain the particular susceptibility of family-kept rabbits, as they are fed potentially contaminated fodder. As the clinically similar fulminating hepatitis in human beings is caused by a diversity of viruses (both RNA and DNA), the disease in Leporidae might also be caused by different viruses.(ABSTRACT TRUNCATED AT 250 WORDS)