Retrospective studies on rabbit haemorrhagic disease outbreaks caused by RHDV GI.2 virus on farms in France from 2013 to 2018

[EN] Rabbit haemorrhagic disease (RHD) is a critical health threat to the rabbit industry in Europe. In 2018, the French rabbit industry adopted a voluntary control plan against this disease. In this context, two epidemiological studies were conducted on RHD outbreaks that occurred between 2013 and 2018 in France. The objectives were to describe the spread of RHD due to the new genotype RHDV GI.2 (rabbit haemorrhagic disease virus GI.2) and to identify rearing factors influencing the occurrence of the disease in order to guide the prevention measures recommended in the control plan. An analysis of cases on 295 farms between 2013 and 2017 showed that 32% of farms were affected at least once; the incidence of the disease increased in 2016-2017 compared to 2013-2015. Farms already affected in 2013-2015 had a higher risk of being infected in 2016-2017 than those that remained unaffected until 2015 (Relative Risk and 95% Confident Interval 1.7 [1.1-2.7]). A case-control study carried out between 2016 and 2018 on 37 outbreaks and 32 control farms revealed variability in biosecurity and decontamination practices between farms. The risk of being infected tends to be linked to these practices, but certain structural factors (e.g. the manure disposal system, transfer of rabbits at weaning) could also influence the risk of virus introduction into farms. In the context of a limited vaccination coverage of the farms (only females are vaccinated), these hypotheses will be studied further, using information from the RHD outbreak monitoring system implemented at the same time as the control plan in 2018.This study was founded by the French Ministry of Agriculture (2017-430 / 170274).Huneau-Salaün, A.; Boucher, S.; Fontaine, J.; Le Normand, B.; Lopez, S.; Maurice, T.; Nouvel, L.... (2021). Retrospective studies on rabbit haemorrhagic disease outbreaks caused by RHDV GI.2 virus on farms in France from 2013 to 2018. 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Nest acceptance, clutch, and oviposition traits are promising selection criteria to improve egg production in cage-free system.

In cage-free systems, laying hens must lay their eggs in the nests. Selecting layers based on nesting behavior would be a good strategy for improving egg production in these breeding systems. However, little is known about the genetic determinism of nest-related traits. Laying rate in the nests (LRN), clutch number (CN), oviposition traits (OT), and nest acceptance for laying (NAL) of 1,430 Rhode Island Red (RIR) hens and 1,008 White Leghorn (WL) hens were recorded in floor pens provided with individual electronic nests. Heritability and genetic and phenotypic correlations of all traits were estimated over two recording periods-the peak (24-43 weeks of age) and the middle (44-64 weeks of age) of production-by applying the restricted maximum likelihood method to an animal model. The mean oviposition time (MOT) ranged from 2 h 5 min to 3 h and from 3 h 35 min to 3 h 44 min after turning on the lights for RIR and WL hens, respectively. The mean oviposition interval ranged from 24 h 3 min to 24 h 16 min. All heritability and correlation estimates were similar for RIR and WL. Low to moderate heritability coefficients were estimated for LRN (0.04-0.25) and moderate to high heritability coefficients for CN and OT (0.27-0.68). CN and OT were negatively genetically correlated with LRN (-0.92 to -0.39) except during peak production for RIR (-0.30 to +0.43). NAL was weakly to moderately heritable (0.13-0.26). Genetic correlations between NAL and other traits were low to moderate (-0.41 to +0.44). In conclusion, CN and OT are promising selection criteria to improve egg production in cage-free systems. NAL can be also used to reduce the number of eggs laid off-nest in these breeding systems. However, variability in MOT must be maintained to limit competition for the nests

Sélectionner sur le comportement au nid pour améliorer la production d'œufs des poules en systèmes alternatifs à la cage

International audienceIn the EU, the majority of laying hens are now raised in cage-free systems (barn, free-range, and organic). In these systems, hens must lay in nests because eggs laid off-nest are usually downgraded, resulting in a loss of income for the farmer. This study aims to identify potential selection criteria on nesting behavior, to improve the laying rate in the nests (LRN). Hens were raised in floor pens. The nesting behavior was recorded continuously, between 24 and 64 weeks of age, with individual electronic nests using radio-frequency identification. LRN was then calculated for each hen, as well as the laying rhythm (clutch number, mean oviposition time, and logarithm of the variance of oviposition time), the mean laying duration (mean time spent in the nests for laying), the mean distance between nests of laying, and the nest acceptance for laying. Genetic parameters (heritability and genetic correlations) for traits were estimated for 927 Rhode Island Red (RIR) and 980 White Leghorn (WL), with an animal model. Heritability estimates of LRN were 0.16 and 0.23 for the RIR and WL lines, respectively. For both lines, laying rhythm traits were more highly heritable (between 0.36 and 0.65) and genetically highly correlated with LRN (between -0.77 and -0.49), except for the mean oviposition time in RIR (-0.06). Heritability estimates from 0.55 and 0.68, 0.31 and 0.38, and 0.20 and 0.17 were reported for, respectively, the mean laying duration, the mean distance between nests of laying, and the nest acceptance for laying. No unfavorable genetic correlation was estimated between these traits and LRN. Selecting for the laying rhythm to improve LRN, while optimizing the occupation rate of the nests, could therefore be an interesting strategy to reduce the off-nest laying. Relationships with the egg qualities must be studied before incorporating these new traits into the breeding programs.Dans l'UE, la majorité des poules pondeuses sont désormais élevées dans des systèmes alternatifs à la cage (sol, plein air et biologique). Dans ces systèmes, les poules doivent pondre dans des nids car les oeufs pondus hors-nid sont généralement déclassés, entrainant une perte de revenus pour l'éleveur. L'objectif de cette étude est d'identifier de potentiels critères de sélection sur le comportement de ponte au nid, afin d'améliorer l'intensité de ponte dans le nid (IPN). Les poules ont été élevées dans des parcs au sol. Le comportement de ponte au nid a été enregistré en continu, entre 24 et 64 semaines d'âge, avec des nids électroniques individuels utilisant l'identification par radiofréquence. IPN a alors pu être calculée pour chaque poule, ainsi que le rythme de ponte (nombre de séries de ponte, heure de ponte moyenne et logarithme de la variance de l'heure de ponte), la durée de ponte moyenne (temps moyen passé au nid pour pondre), la distance moyenne séparant les nids de ponte et l'utilisation des nids pour la ponte. Les paramètres génétiques (héritabilités et corrélations génétiques) de tous ces caractères ont été estimés pour 927 Rhode Island Red (RIR) et 980 White Leghorn (WL), avec un modèle animal. L'héritabilité de IPN était de 0,16 et 0,23 pour les lignées RIR et WL respectivement. Pour les deux lignées, les caractères de rythme de ponte se sont révélés plus fortement héritables (entre 0,36 et 0,65) et génétiquement très corrélés à IPN (entre-0,77 et-0,49), à l'exception de l'heure de ponte moyenne pour RIR (-0,06). Des héritabilités de 0,55 et 0,68, de 0,31 et 0,38 et de 0,20 et 0,17 ont été estimées pour, respectivement, la durée de ponte moyenne, la distance moyenne séparant les nids de ponte et l'utilisation des nids. Aucune corrélation génétique défavorable n'a été estimée entre ces caractères et IPN. Sélectionner sur le rythme de ponte afin d'améliorer plus rapidement IPN, tout en optimisant l'occupation des nids, pourrait donc être une stratégie intéressante pour réduire la ponte hors-nid. Les relations avec les qualités de l'oeuf doivent être étudiées avant d'intégrer ces nouveaux caractères dans le schéma de sélection

Genetic parameters for the oviposition time using high-throughput phenotyping from individual electronic nests in laying hens

International audienceOviposition time is a predictor of the laying rhythm. Drift in oviposition time (i.e. more than 24h between 2 oviposition times) can lead the hen to make a pause day. The recent availability of an individual electronic nest enables high-throughput phenotyping of laying behavior like the record of Daily Oviposition Time (DOT). In this study, the genetic background of DOT along the production time was investigated through the estimation of heritability coefficients for 10 successive periods. For the genetic evaluation purpose, the use of the mean or the variance of DOT per hen, instead of the repeated data, to estimate the breeding values of hens was then considered.Data were continuously recorded on laying hens raised in a barn thanks to individual electronic nests, which use radio-frequency identification of hens. The oviposition time was recorded on 1,180 Rhode Island Red hens (RIR) and 932 White Leghorn hens (WL) between 24 and 64 weeks of age. Heritability coefficients of DOT were estimated for 10 periods of 28-days between 24 and 64 weeks of age, using REML methodology applied to an animal model. Heritability coefficients of DOT, of the mean of DOT per hen (MOT) and the Logarithm of the DOT Variance per hen (LVOT) were estimated for the whole period (24 to 64 weeks of age) and the Estimated Breeding Values (EBVs) of hens for DOT, MOT and LVOT were compared.Earliest recorded DOT was 2h05 and 3h07 after turning on the light for RIR and WL respectively. According to the period of 28-days, low to moderate heritability was estimated for DOT with values ranging from 0.28 ± 0.06 and 0.42 ± 0.07 for RIR, and 0.13 ± 0.03 and 0.24 ± 0.05 for WL. For the whole period, moderate to high heritability was estimated for MOT (0.73 ± 0.08 for RIR and 0.56 ± 0.08 for WL), and LVOT (0.42 ± 0.07 for RIR and 0.45 ± 0.08 for WL). The Spearman correlations between the EBVs of hens for DOT and MOT were 0.99 in both lines. The Spearman correlations between the EBVs of hens for DOT and LVOT were 0.87 and 0.65 for RIR and WL respectively.These results indicate that DOT captures genetic information closer to MOT than LVOT. The rankings of candidates are the same for MOT and DOT. However, the calculation time of EBVs is faster for MOT than for DOT, suggesting that MOT is more interesting for the genetic evaluations. The existence of genetic background for the oviposition time is promising to identify candidate genes implicated in the expression of the laying rhythm

The ways of progress to limit severe pecking in laying hens: Etude épidémiologique et expérimentale sur la poule élevée en cage aménagée et au sol avec accès plein-air

The beak-trimming is systematically practiced in France on laying hens in order to limit the negativeconsequences of severe pecking behaviour. However, this practice is being challenged by civil societyand is being banned in several European countries. In this context, the project named “Epointage”, wasinitiated in order to test different ways of progress with the objective of limiting severe pecking in layinghens. This study took place between 2015 and 2018 and began with an epidemiological survey. Thepurpose of this study was to determine the extent of severe pecking problems in French laying henfarms (free-range with outdoor access and furnished cages) as well as better understand the factorsassociated with this behavior. Another part of this study aimed at proposing practical solutions forfarmers to raise unbeak-trimmed hens while preserving their welfare and health, by testing the effects ofdifferent enrichment solutions for pullets and laying hens. To meet these needs, three experimentaltests were carried out. The main results of this work are presented in this synthesis and have led torecommendations in technical sheets.L’épointage du bec est systématiquement pratiqué en France sur les poules pondeuses afin de limiterles conséquences négatives du picage sévère. Toutefois, cette pratique est remise en question par lasociété civile et en cours d’interdiction dans plusieurs pays européens. Dans ce contexte, le projetEpointage a été initié afin de tester différentes voies de progrès, dans l’objectif de limiter le picagesévère chez la poule pondeuse. Cette étude s’est déroulée entre 2015 et 2018 et a débuté par laréalisation d’une enquête épidémiologique. Celle-ci avait pour but de déterminer l’ampleur desproblèmes de picage dans les élevages de poules pondeuses en France (sol avec accès plein-air et encages aménagées) et de mieux comprendre les facteurs associés à ce comportement. Un autre voletde cette étude visait à proposer aux éleveurs des solutions pratiques pour élever des poules nonépointées tout en préservant leur bien-être et leur santé, en testant l’intérêt de différentes solutionsd’enrichissement chez des poules aux becs intacts ou épointées. Pour y répondre, trois essaisexpérimentaux ont été réalisés. Les résultats principaux de ces travaux sont présentés dans cettesynthèse et ont conduit à des recommandations sous forme de fiches techniques pour la filière

Husbandry Practices, Health, and Welfare Status of Organic Broilers in France

Organic poultry production has increased sharply with growing consumer demand in the context of sustainable development. A study was conducted in 85 organic broiler flocks between 2014 and 2015 to describe the husbandry practices and the health and welfare status of organic broilers in France, and to study farming diversity by comparing independent farms (Ind farms, n = 15) with direct sales to farms working with companies (Comp farms, n = 70). Each flock was visited at 3 and 11 weeks of age to collect data on farming conditions, health disorders, and mortality. Welfare notation of 30 broilers per flock and parasitic examination of 5 broilers per flock was also performed. Findings showed significantly different farming management between Ind farms and Comp farms, with smaller flocks on the Ind farms (476 broilers/house vs. 3062 broilers/house, p < 0.01) more frequently in mobile houses. The mean mortality rate was 2.8%, mainly involving digestive disorders. Helminths were detected in 58.8% of the flocks. On average, 21.9% and 5.8% of broilers in a flock had footpad dermatitis and dirty feathers, respectively. The health and welfare characteristics of organic broilers on Ind farms vs. Comp farms were not significantly different, except dirtier feathers and more footpad dermatitis on Ind farms (19.1% vs. 2.9%, p = 0.03 and 39.6% vs. 18.1%, p = 0.02, respectively), associated with poultry housing conditions in mobile houses (p < 0.01). This study provides greater insight into farming sustainability aspects related to the husbandry practices, and the health and welfare of organic broilers in France

Brominated flame retardants in broiler chickens

Brominated flame retardants in broiler chickens. XVII. European symposium on the quality of eggs and egg products. XXIII. European Symposium on the Quality of Poultry Mea