Extensive genetic progress has been achieved in dairy cattle populations on many traits of economic importance because of efficient breeding programmes. Success of these programmes has relied on progeny testing of the best young males to accurately assess their genetic merit and hence their potential for breeding. Over the last few years, the integration of dense genomic information into statistical tools used to make selection decisions, commonly referred to as genomic selection, has enabled gains in predicting accuracy of breeding values for young animals without own performance. The possibility to select animals at an early stage allows defining new breeding strategies aimed at boosting genetic progress while reducing costs. The first objective of this article was to review methods used to model and optimize breeding schemes integrating genomic selection and to discuss their relative advantages and limitations. The second objective was to summarize the main results and perspectives on the use of genomic selection in practical breeding schemes, on the basis of the example of dairy cattle populations. Two main designs of breeding programmes integrating genomic selection were studied in dairy cattle. Genomic selection can be used either for pre-selecting males to be progeny tested or for selecting males to be used as active sires in the population. The first option produces moderate genetic gains without changing the structure of breeding programmes. The second option leads to large genetic gains, up to double those of conventional schemes because of a major reduction in the mean generation interval, but it requires greater changes in breeding programme structure. The literature suggests that genomic selection becomes more attractive when it is coupled with embryo transfer technologies to further increase selection intensity on the dam-to-sire pathway. The use of genomic information also offers new opportunities to improve preservation of genetic variation. However, recent simulation studies have shown that putting constraints on genomic inbreeding rates for defining optimal contributions of breeding animals could significantly reduce achievable genetic gain. Finally, the article summarizes the potential of genomic selection to include new traits in the breeding goal to meet societal demands regarding animal health and environmental efficiency in animal production.

The objective of this study was to determine the concentration of total selenium (Se) and the proportions of total Se comprised as selenomethionine (SeMet) and selenocysteine (SeCys) in the postmortem tissues of female pheasants (Phasianus Colchicus Torquator) offered diets that contained graded additions of selenised-enriched yeast (SY) or a single comparative dose of sodium selenite (SS). Thiobarbituric acid reactive substances (TBARS) and tissue glutathione peroxidase (GSH-Px) activity of breast (Pectoralis Major) were assessed at 0 and 5 days postmortem. A total of 216 female pheasant chicks were enrolled into the study. Twenty-four birds were euthanased at the start of the study, and samples of blood, breast muscle, leg muscle (M. Peroneus Longus and M. Gastrocnemius), heart, liver, kidney and gizzard were collected for determination of total Se. Remaining birds were blocked by live weight and randomly allocated to one of four dietary treatments (n = 48 birds/treatment) that either differed in Se source (SY v. SS) or dose (control (0.17 mg total Se/kg), SY-L and SS-L (0.3 mg/kg total Se as SY and SS, respectively) and SY-H (0.45 mg total Se/kg)). Following 42 and 91 days of treatment, 24 birds per treatment were euthanased, and samples of blood, breast muscle, leg muscle, heart, liver, kidney and gizzard were retained for determination of total Se and the proportion of total Se comprised as SeMet or SeCys. Whole blood GSH-Px activity was determined at each time point. Tissue GSH-Px activity and TBARS were determined in breast tissue at the end of the study. There were increases in both blood and tissues to the graded addition of SY to the diet (P < 0.001), but the same responses were not apparent with the blood and tissues of selenite-supplemented birds receiving a comparable dose (SY-L v. SS-L). Although there were differences between tissue types in the distribution of SeMet and SeCys, there were few differences between treatments. There were effects of treatment on erythrocyte GSH-Px activity (P = 0.012) with values being higher in treatments SY-H and SS-L when compared with the negative control and treatment SY-L. There were no effects of treatment on tissue GSH-Px activity, which is reflected in the overall lack of any treatment effects on TBARS.

Health in relation to tail-biting behaviour was investigated on a problem farm. Quartets (n = 16) of age- and gender-matched fattening pigs including a tail biter (TB, n = 16), a victim (V, n = 16), a control in the same pen (Ctb, n = 10) and a control in a pen where no tail biting was observed (Cno, n = 14) were chosen by direct behavioural observation. Haematological and clinicochemical analyses, autopsy and histological examination of 16 different tissues were carried out. Tail lesion severity was evaluated both macroscopically, on the basis of inspection, and histologically, in the sagittally cut tail. Category effects were tested using Friedman's ANOVA by Ranks, Cochran's Q or a repeated-measure GLM and, if significant, pair-wise tests were conducted using Wilcoxon Signed Ranks or McNemar's Test. The number of received tail bites correlated better with histological than with macroscopic tail lesion scoring because of deep inflammation beneath healthy skin in some cases. Most individuals had mild inflammatory lesions in internal organs suggestive of generalized activation of the immune system, and 30% of the animals were anaemic, possibly because of systemic spread of infectious agents. V had more severe respiratory organ lesions and higher serum protein concentrations than all other categories of pigs. Liver- and muscle-specific enzymes (alanine aminotransferase, alkaline phosphatase and creatine kinase) differed between categories. In conclusion, most animals had signs of generalized activation of the immune system, possibly because of systemic spread of infectious agents. V pigs suffered from more severe inflammatory lesions than TB, Ctb or Cno. Deep infections may exist under healthy skin in the tail of bitten pigs.

This study evaluated effects of farming practice scenarios aiming to reduce greenhouse gas (GHG) emissions and subsequent alternative land use on environmental impacts of a beef cattle production system using the life cycle assessment approach. The baseline scenario includes a standard cow–calf herd with finishing heifers based on grazing, and a standard bull-fattening herd using a diet mainly based on maize silage, corresponding to current farm characteristics and management by beef farmers in France. Alternative scenarios were developed with changes in farming practices. Some scenarios modified grassland management (S1: decreasing mineral N fertiliser on permanent grassland; S2: decreasing grass losses during grazing) or herd management (S3: underfeeding of heifers in winter; S4: fattening female calves instead of being reared at a moderate growth rate; S5: increasing longevity of cows from 7 to 9 years; S6: advancing first calving age from 3 to 2 years). Other scenarios replaced protein sources (S7: partially replacing a protein supplement by lucerne hay for the cow–calf herd; S8: replacing soya bean meal with rapeseed meal for the fattening herd) or increased n-3 fatty acid content using extruded linseed (S9). The combination of compatible scenarios S1, S2, S5, S6 and S8 was also studied (S10). The impacts, such as climate change (CC, not including CO2 emissions/sequestration of land use and land-use change, LULUC), CC/LULUC (including CO2 emissions of LULUC), cumulative energy demand, eutrophication (EP), acidification and land occupation (LO) were expressed per kg of carcass mass and per ha of land occupied. Compared with the baseline, the most promising practice to reduce impacts per kg carcass mass was S10 (all reduced by 13% to 28%), followed by S6 (by 8% to 10%). For other scenarios, impact reduction did not exceed 5%, except for EP (up to 11%) and LO (up to 10%). Effects of changes in farming practices (the scenarios) on environmental impacts varied according to impact category and functional unit. For some scenarios (S2, S4, S6 and S10), permanent grassland area and LO per kg of carcass decreased by 12% to 23% and 9% to 19%, respectively. If the ‘excess’ permanent grassland was converted to fast-growing conifer forest to sequester carbon in tree and soil biomass, CC/LULUC per kg of carcass could be reduced by 20%, 25%, 27% and 48% for scenarios S2, S4, S6 and S10, respectively. These results illustrate the potential of farming practices and forest as an alternative land use to contribute to short- and mid-term GHG mitigation of beef cattle production systems.

To reduce mortality among suckling piglets, lactating sows are traditionally housed in farrowing crates. Alternatively, lactating sows can be housed in farrowing pens where the sow is loose to ensure more behavioural freedom and consequently a better welfare for the sow, although under commercial conditions, farrowing pens have been associated with increased piglet mortality. Most suckling piglets that die do so within the first week of life, so potentially lactating sows do not have to be restrained during the entire lactation period. Therefore, the aim of the current study was to investigate whether confinement of the sow for a limited number of days after farrowing would affect piglet mortality. A total of 210 sows (Danish Landrace × Danish Yorkshire) were farrowed in specially designed swing-aside combination farrowing pens measuring 2.6 m × 1.8 m (combi-pen), where the sows could be kept loose or in a crate. The sows were either: (a) loose during the entire experimental period, (b) crated from days 0 to 4 postpartum, (c) crated from days 0 to 7 postpartum or (d) crated from introduction to the farrowing pen to day 7 postpartum. The sows and their subsequent litters were studied from introduction to the combi-pen ∼1 week before expected farrowing and until 10 days postpartum. Confinement period of the sow failed to affect the number of stillborn piglets; however, sows that were crated after farrowing had fewer live-born mortality deaths (P < 0.001) compared with the sows that were loose during the experimental period. The increased piglet mortality among the loose sows was because of higher mortality in the first 4 days after farrowing. In conclusion, the current study demonstrated that crating the sow for 4 days postpartum was sufficient to reduce piglet mortality.

Improvement of reproduction in dairy cows has become a major challenge in dairy production. We have recently shown that dairy cows carrying the ‘fertil−’ haplotype for one quantitative trait locus (QTL), affecting female fertility and located on the bovine chromosome 3, had a significantly lower conception rate after the first artificial insemination than cows carrying the ‘fertil+’ haplotype. The objective of this paper was to study other phenotypic modifications linked to this QTL. In the present study, 23 ‘fertil+’ and 18 ‘fertil−’ cows were characterized for live weight, milk production, food intake, eating behaviour and plasma metabolites. These parameters were measured during the first lactation, from calving to 40 weeks postpartum (wkpp). In the first 7 weeks of lactation, ‘fertil+’ primiparous cows had a significantly higher live BW and milk production than ‘fertil−’ cows. Dry matter intake tended to be slightly higher for ‘fertil+’ than for ‘fertil−’ primiparous cows in this period. However, energy balance was similar for the two haplotypes in the whole lactation, except in the first wkpp, and consequently, could not explain their different fertility. The major observation concerned the eating behaviour. ‘Fertil+’ primiparous cows had a significantly lower eating rate than ‘fertil−’ cows during the 40 weeks of lactation. In parallel, ‘fertil+’ cows spent significantly more time at the feeder for a similar number of visits than ‘fertil−’ cows. Furthermore, no differences in plasma concentrations of non-esterified fatty acids and insulin were observed between the two haplotypes. Plasma glucose was significantly lower in ‘fertil+’ than in ‘fertil−’ cows in the second wkpp. Taken together, our results show that ‘fertil+’ and ‘fertil−’ dairy cows, with different fertility, have also different eating behaviour without any variation in energy balance, except in the first week of lactation.

The impact of fibre level and fibre source on digestibility, gastrointestinal tract (GIT) development, total tract mean retention time (MRT) and growth performance was studied in indigenous Mong Cai (MC) and exotic Landrace × Yorkshire (LY) pigs. The diets were based on maize, rice bran, soyabean meal, fish meal and soyabean oil, and cassava residue (CR) or brewer's grain (BG) as fibrous ingredient sources in the high-fibre diets (HF) and were fed ad libitum. A low-fibre diet (LF), containing around 200 g NDF/kg dry matter (DM), was formulated without CR and BG as feed ingredients. The HF diets (HF-CR and HF-BG) were formulated to contain around 270 g NDF/kg DM. The experiment was arranged as a 2 × 3 factorial completely randomized design with six replications, and lasted 27 days. Increased dietary fibre level resulted in a reduction (P < 0.05) in average daily gain, digestibility of organic matter (OM), CP and gross energy (GE) at the ileum and in the total tract, and in MRT, and an increase (P < 0.05) in the feed conversion ratio and in the weight of the GIT (except for small intestine and caecum). The coefficients of total tract digestibility of fibre fractions were higher in HF diets than in the LF diet, with highest values for diet HF-CR, which had a high proportion of soluble non-starch polysaccharides. MC pigs had longer MRT of digesta than LY pigs (P < 0.05), resulting in higher digestibility at the ileum and in the total tract. Across diets and breeds, the total tract apparent digestibility of OM, CP and GE was positively related (R2 = 0.80 to 0.84) to the MRT of solids, whereas the MRT was negatively related to the DM intake (R2 = 0.60).

Mixed crop–livestock systems, combining livestock and cash crops at farm level, are considered to be suitable for sustainable intensification of agriculture. Ensuring the survival of mixed crop–livestock systems is a challenge for European agriculture: the number of European mixed crop–livestock farms has been decreasing since 1970. Analysis of farming system dynamics may elucidate past changes and the forces driving this decline. The objectives of this study were (i) to identify the diversity of paths that allowed the survival of mixed crop–livestock farming and (ii) to elucidate the driving forces behind such survival. We analysed the variety of farm trajectories from 1950 to 2005. We studied the entire farm population of a case study site, located in the ‘Coteaux de Gascogne’ region. In this less favoured area of south-western France, farmers have limited specialisation. Currently, half of the farms use mixed crop–livestock systems. The data set of 20 variables for 50 farms on the basis of six 10-year time steps was collected through retrospective surveys. We used a two-step analysis including (i) a visual assessment of the whole population of individual farm trajectories and (ii) a computer-based typology of farm trajectories on the basis of a series of multivariate analyses followed by automatic clustering. The European Common Agricultural Policy, market globalisation and decreasing workforce availability were identified as drivers of change that favoured the specialisation process. Nevertheless, farmers’ choices and values have opposed against these driving forces, ensuring the survival of some mixed crop–livestock farming systems. The trajectories were clustered into five types, four of which were compatible with mixed crop–livestock systems. The first type was the maximisation of autonomy by combining crops and livestock. The second type was diversification of production to exploit economies of scope and protect the farm against market fluctuations. The other two types involved enlargement and progressive adaptation of the farm to the familial workforce. The survival of mixed crop–livestock systems in these two types is largely dependent on workforce availability. Only one type of trajectory, on the basis of enlargement and economies of scale, did not lead to mixed crop–livestock systems. In view of the current evolution of the driving forces, maximising autonomy and diversification appear to be suitable paths to deal with current challenges and maintain mixed crop–livestock systems in Europe.

Forty-two New Zealand White male rabbits were housed individually in wire cages and randomly distributed among six experimental groups of seven rabbits each, during 16 to 61 weeks of age. There were three main nitrate groups: 0 (tap water), 350 and 700 ppm. Within the 700 ppm of nitrate, there were four subgroups, in which one group was used as control group and the other three groups were supplemented with either 200 ppm of ascorbic acid (vitamin (Vit) C), 200 ppm of Vit E with 0.2 ppm of selenium (Se) and 1000 ppm of probiotic. The nitrate was supplemented as a sodium nitrate. The aim is to test the ability of Vit C and Vit E, Se and probiotic on the deleterious effects (blood and seminal plasma biochemical constituents, semen quality and productive performance) of nitrate in drinking water. Rabbits given nitrate at 700 ppm had significantly lower plasma globulin, red blood cells (RBCs), hemoglobin (Hgb), packed cell volume % (PCV%) and total antioxidant capacity (TAC) than those given the other concentrations of nitrate. Vit C, Vit E with Se and probiotic resulted in significantly (P < 0.05) greater Hgb, RBCs, PCV% and TAC than those of bucks given water supplemented with only 700 ppm nitrate, but the aspartate aminotransferase and alanine aminotransferase concentrations in seminal plasma were lower. Testosterone in the blood plasma and the seminal plasma was significantly (P < 0.05) lower in rabbits given 700 ppm nitrate than in those given other concentrations of nitrate. Vit C, Vit E with Se and the probiotic significantly increased testosterone, fertility, number of offspring and total offspring weight of rabbits sired by bucks supplemented with 700 ppm of nitrate.

Heritability is a central element in quantitative genetics. New molecular markers to assess genetic variance and heritability are continually under development. The availability of molecular single nucleotide polymorphism (SNP) markers can be applied for estimation of variance components and heritability on population, where relationship information is unknown. In this study, we evaluated the capabilities of two Bayesian genomic models to estimate heritability in simulated populations. The populations comprised different family structures of either no or a limited number of relatives, a single quantitative trait, and with one of two densities of SNP markers. All individuals were both genotyped and phenotyped. Results illustrated that the two models were capable of estimating heritability, when true heritability was 0.15 or higher and populations had a sample size of 400 or higher. For heritabilities of 0.05, all models had difficulties in estimating the true heritability. The two Bayesian models were compared with a restricted maximum likelihood (REML) approach using a genomic relationship matrix. The comparison showed that the Bayesian approaches performed equally well as the REML approach. Differences in family structure were in general not found to influence the estimation of the heritability. For the sample sizes used in this study, a 10-fold increase of SNP density did not improve precision estimates compared with set-ups with a less dense distribution of SNPs. The methods used in this study showed that it was possible to estimate heritabilities on the basis of SNPs in animals with direct measurements. This conclusion is valuable in cases when quantitative traits are either difficult or expensive to measure.

Erythropoietin (EPO) gene therapy can be used for several purposes; however, its effects on reproductive performance are unknown. The aim of this study was to evaluate the toxicological effects of non-viral (EPO) gene transfer on sperm motility, viability, morphology and concentration. Rabbit EPO cDNA was cloned into a pTarget mammalian expression vector. Rabbits were administered with: (1) pTarget/EPO vector, (2) recombinant human EPO (rHuEpo) and (3) saline (control). Both pTarget/EPO and rHuEpo significantly increased (P < 0.05) hematocrit levels 1 week after injection and they remained significantly higher than the control for up to 5 weeks (P < 0.05), showing that both EPO treatments were effective in stimulating the production of red blood cells in rabbits. The EPO gene transfer or rHuEPO administration had no significant effect (P > 0.05) on sperm motility, vigor, viability, concentration or morphology in the testis.

Data from 113 Dutch organic farms were analysed to determine the effect of cross-breeding on production and functional traits. In total, data on 33 788 lactations between January 2003 and February 2009 from 15 015 cows were available. Holstein–Friesian pure-bred cows produced most kg of milk in 305 days, but with the lowest percentages of fat and protein of all pure-bred cows in the data set. Cross-breeding Holstein dairy cows with other breeds (Brown Swiss, Dutch Friesian, Groningen White Headed, Jersey, Meuse Rhine Yssel, Montbéliarde or Fleckvieh) decreased milk production, but improved fertility and udder health in most cross-bred animals. In most breeds, heterosis had a significant effect (P < 0.05) on milk (kg in 305 days), fat and protein-corrected milk production (kg in 305 days) and calving interval (CI) in the favourable direction (i.e. more milk, shorter CI), but unfavourably for somatic cell count (higher cell count). Recombination was unfavourable for the milk production traits, but favourable for the functional traits (fertility and udder health). Farm characteristics, like soil type or housing system, affected the regression coefficients on breed components significantly. The effect of the Holstein breed on milk yield was twice as large in cubicle housing as in other housing systems. Jerseys had a negative effect on fertility only on farms on sandy soils. Hence, breed effects differ across farming systems in the organic farming and farmers can use such information to dovetail their farming system with the type of cow they use.

The aim of this study was to assess the effect of natural light and straw bales on activity levels and leg health in commercial broiler chickens. Houses containing ∼23 000 broiler chickens were assigned to one of four treatments in a 2 × 2 factorial design. Treatments involved two levels of access to natural light (NL) (present ‘+NL’, or absent ‘−NL’) and two levels of access to straw bales (SB) (present (30/house) ‘+SB’, or absent ‘−SB’). All houses were windowed and artificially lit, and windows were shuttered where appropriate. Treatments were applied in one of the two houses on each of the two farms, and were replicated over four production cycles. Behaviour was observed in 2 to 6 weeks of the cycle. This involved observations of general behaviour and activity, gait scores (0 (perfect) to 5 (unable to walk)) and latency to lie (measured in seconds from encouraging a bird to stand). Production performance and environmental parameters were also measured. Average daytime light intensity and UV levels in the +NL treatment were 85.2 lx and 3.37 μW/cm2, respectively, and in the −NL treatment were 11.4 lx and 0 μW/cm2, respectively. Litter moisture levels were lower with NL treatment (P < 0.05), but were not affected by SB (P > 0.05). The percentage of time spent lying was significantly reduced by the provision of NL (P < 0.01), but not by SB (P > 0.05). There were three-way interactions between NL, SB and bird age on the percentage of time spent in locomotion (P < 0.05) and idling (P < 0.05). Both treatment factors had inconsistent effects on these parameters across different weeks. Levels of preening, resting and aggressive behaviour were not affected by treatment (P > 0.05). There was an interaction between treatments in average gait scores, with higher scores in the −NL−SB treatment than in all other treatments, and higher in the −NL+SB treatment than in the +NL treatments (P < 0.001). Average latency to lie was significantly higher with NL (P < 0.001) and SB (P < 0.05). We conclude that environmental modifications have the potential to increase activity levels and improve the leg health of commercial broilers. The light environment appears to be particularly important in this respect.

The aim of the present study was to evaluate the protective effects of isoflavone (ISO) against zearalenone (ZEA) residues in the muscle and liver tissues of prepubertal gilts. Seventy 75-day-old, prepubertal, female pigs (Duroc × Landrace × Yorkshire, 26.5 ± 0.60 kg) were allocated randomly to seven diet treatments for 21days as follows: one control group (fed the basal diet) and six groups fed the basal diet with the addition of either 0.5 or 2.0 mg/kg ZEA plus either 0, 300 or 600 mg/kg ISO. The results showed that the diet with 2.0 mg/kg ZEA added caused an increase of ZEA residue level in muscle tissue (P < 0.05), and that the addition of both 0.5 and 2.0 mg/kg ZEA increased the residue level of ZEA in the liver of prepubertal gilts (P < 0.05). Addition of 600 mg/kg ISO to 2.0 mg/kg ZEA-contaminated diet decreased the ZEA residue level in liver tissue (P < 0.05), and the addition of 300 or 600 mg/kg ISO to the 2.0 mg/kg ZEA-contaminated diet decreased the residue levels of ZEA in muscle tissue (P < 0.05). Western blot analysis demonstrated that feeding ZEA to prepubertal gilts increased their protein expression of 3α/3β-hydroxysteroid dehydrogenase (HSD; P < 0.05), and that the addition of 300 or 600 mg/kg ISO to the 2.0 mg/kg ZEA-contaminated diet decreased the protein expression of 3α/3β-HSD (P < 0.05), compared with the addition of 2.0 mg/kg ZEA alone. The results demonstrated that muscle and liver tissues retain residual ZEA when pigs are fed a diet contaminated with high concentrations of ZEA, and that the concentration of ZEA in muscle and liver tissues increased with increased amounts of ZEA in the feed. In diets contaminated with high levels of ZEA, the addition of ISO may accelerate the biotransformation and degradation of ZEA and its metabolites, and reduce the residues of ZEA in liver and muscle tissues of prepubertal gilts.

Genetic studies on taste sensitivity, and bitter taste receptors (T2R) in particular, are an essential tool to understand ingestive behavior and its relation to variations of nutritional status occurring in ruminants. In the present study, we conducted a data-mining search to identify T2R candidates in sheep by comparison with the described T2R in cattle and using recently available ovine genome. In sheep, we identified eight orthologs of cattle genes: T2R16, T2R10B, T2R12, T2R3, T2R4, T2R67, T2R13 and T2R5. The in silico predicted genes were then confirmed by PCR and DNA sequencing. The sequencing results showed a 99% to 100% similarity with the in silico predicted sequence. Moreover, we address the chromosomal distribution and compare, in homology and phylogenetic terms, the obtained genes with the known T2R in human, mouse, dog, cattle, horse and pig. The eight novel genes identified map either to ovine chromosome 3 or 4. The phylogenetic data suggest a clustering by receptor type rather than by species for some of the receptors. From the species analyzed, we observed a clear proximity between the two ruminant species, sheep and cattle, in contrast with lower similarities obtained for the comparison of sheep with other mammals. Although further studies are needed to identify the complete T2R repertoire in domestic sheep, our data represent a first step for genetic studies on this field.

The aim of this study was to analyse the effects of species (Muscovy and Pekin ducks) and age at the beginning of the overfeeding period on fatty liver production, carcass composition and lipid and moisture content of the liver and breast muscle. We reared four groups of 40 ducks per species for the study, starting at 2-week intervals in order to have four different ages together at the beginning of the overfeeding period (10, 12, 14 and 16 weeks). At the end of the overfeeding period, all ducks were slaughtered. Our results confirmed the high levels of difference in carcass composition and lipid content in the plasma, liver and breast muscle between Muscovy and Pekin ducks at all ages. Pekin ducks were not able to develop a high degree of hepatic steatosis, but had increased lipid storage in peripheral adipose and muscle tissues than Muscovy ducks. However, the fatty liver weight of Pekin ducks increased with age, with lipid deposition in the liver and peripheral tissues. The ability of Muscovy ducks to produce fatty livers remained unchanged with age in line, with lipid deposition in the liver and peripheral tissues. The sites of lipid deposition thus depend on species and not on the physiological maturity of ducks.

During growth (27 to 75 days of age), a total of 384 rabbits were kept in 72 individual cages, 48 bicellular cages (2 rabbits/cage) and 24 collective cages (9 rabbits/cage). To evaluate the effects of the housing system on the fear level and behavioural patterns of rabbits at the two ages (39 to 45 days and 66 to 73 days), a tonic immobility test and an open-field test were conducted and their behaviour was video recorded. In the tonic immobility test, the number of attempts to induce immobility (1.38) was lower, and the duration of immobility (47.8 s) was higher (0.05 < P < 0.01) in the rabbits housed in individual cages than in those kept in bicellular (1.72 attempts and 25.0 s of immobility) and collective cages (1.99 attempts and 25.0 s of immobility). During the open-field test, the rabbits from individual and bicellular cages showed higher latency (38.8 and 40.3 v. 27.0 s), a lower number of total (73.3 and 81.7 v. 91.9) and central displacements (3.6 and 2.8 v. 5.4) and a shorter running time (11.8 and 13.6 s v. 17.7 s) and the time biting the pen (5.5 and 9.1 s v. 28.2 s) compared with the rabbits kept in collective cages (0.05 < P < 0.001). During the 24-h video recording, the rabbits in individual and bicellular cages spent less time allogrooming (0.34% and 0.19% v. 1.44%), moving (0.74% and 0.60% v. 1.32%) and running (0.08% and 0.03% v. 0.21%) than the rabbits in the collective cages (0.01 < P < 0.001). The lowest numbers of alerts and hops were observed in the rabbits kept in bicellular cages. With increasing age, a lower number of rabbits were sensitive to the immobility test and more rabbits entered the pen spontaneously during the open-field test (P < 0.001). In conclusion, the rabbits in individual cages exhibited the highest fear level and incomplete behavioural patterns; the rabbits housed in collective cages showed the lowest fear levels and had the possibility of expressing a wider range of behaviour; and the rabbits in bicellular cages exhibited an inconsistent pattern of fear in the tonic immobility and open-field tests. Probably, these rabbits were in a less stressful condition compared with animals in individual cages because social contacts were allowed, even if freedom of movement was more limited.

During growth (from 27 to 75 days of age), 384 rabbits were kept in different types of wire-net cages: 72 individual cages (72 rabbits; 10 animals/m2), 48 bicellular cages (96 rabbits; 2 rabbits/cage; 18 animals/m2) and 24 collective cages (216 rabbits; 9 rabbits/cage; 18 animals/m2). The rabbits housed in individual cages showed higher daily weight gain both during the fattening period (from 52 to 75 days of age) and during the whole period of growth (43.0 v. 41.8 and 41.5 g/day; P < 0.05), and they had a higher final live weight at 75 days of age (2678 v. 2619 and 2602 g; P < 0.05) compared with the rabbits in the bicellular and collective cages, respectively. Rabbits in individual cages ingested more feed (133 v. 127 and 126 g/day; P < 0.01), but the feed conversion did not differ significantly among rabbits housed in the three types of cages. At slaughter, the carcass traits and meat quality were weakly affected by the housing system. The transport losses were higher in rabbits kept in individual and bicellular cages compared with those reared in collective cages (3.1% and 2.9% v. 2.2%; P < 0.01). In rabbits kept in individual cages, the hind leg muscle to bone ratio was higher (6.35 v. 6.19 and 5.91; P < 0.05) compared with the bicellular and collective cages, respectively. The pH and colour of the longissimus lumborum did not change with the housing system, while the b* index of the biceps femoris was lower (3.04 and 3.32 v. 4.26; P < 0.001) in the rabbits kept in individual and bicellular cages, respectively, than in those kept in collective cages. In conclusion, the rabbits housed in individual cages showed higher daily growth than rabbits kept in bicellular or collective cages, but they had a similar feed conversion and carcass quality. Differently, neither in vivo performance nor slaughter results differed among the rabbits kept in bicellular cages or in collective cages. The meat colour may be affected by the housing system, but to an extent that is hardly perceivable by the final consumer.

The objective of this study was to develop and validate a time-resolved immunofluorometric assay (TR-IFMA) for porcine salivary chromogranin A (CgA) measurements, using a species-specific antibody, and evaluate its behaviour in an acute stress model. Polyclonal antibodies were produced in rabbits immunized with a synthetic porcine fragment of CgA359−379 and used to develop a sandwich TR-IFMA. This TR-IFMA was analytically validated and showed intra- and inter-assay coefficients of variation of 6.23% and 5.82%, respectively, an analytical limit of detection of 4.27 × 10−3 μg/ml and a limit of quantification of 24.5 × 10−3 μg/ml. The assay also demonstrated a high level of accuracy, as determined by linearity under dilution (r = 0.975) and recovery tests. When a model of experimental acute stress, in which animals were immobilized for 3 min with a nose snare (stressor stimulus), was applied, a significant increase (P < 0.05) in CgA levels in saliva was detected at 15 min post-stressor stimulus. These results indicate that the assay developed in this study could measure CgA in porcine saliva in a reliable way and that the concentrations of CgA in saliva samples of pigs increase after an acute stress situation.