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The type of suckling of lambs at early age can strongly affect their performance and ability to adapt to challenges.Genetic selection may help to increase efficiency, and consequently improve adaptation to constraints. This studyaims to investigate the separate and interactive effects of early experience (artificial (AA) vs maternal (AM) rearing)and genetic line on feed efficiency (more efficient (EFF+) vs less efficient (EFF-)), using 80 Romane ewe lambs in afree-range system. AM ewe lambs were reared on free-range pasture with their mothers from birth, and weaned atD90. AA ewe lambs were reared indoors, weaned at D40 and then kept indoors until D100. From D100 to D200,AA and AM lambs were kept on free-range pasture, in separate groups. Regular weighing and blood samplingallowed monitoring growth and levels of certain metabolites, between D0 and D200. Behavioural activity was alsoobserved. Over the 3 weeks following transitioning to pasture, AA grew much less than AM lambs, and a significantdifference in weight was still observed 3.5 months later. Following transitioning to pasture, AA lambs showedsignificantly lower feeding activity and greater exploration time than AM lambs. After 10 weeks of grazing, thesedifferences had mostly subsided. Genetic line had no impact on behavioural activity or growth, apart from atendency to reduced growth of EFF- lambs between D90 and D200. Three weeks after transitioning to pasture,compared to AM, AA lambs had a metabolism oriented towards mobilisation of energy reserves, with greater NEFAD120 and D135 and lower blood glucose levels D135. These same days, urea levels were also lower, suggestinglower nitrogen ingestions. D120 and D135, compared to the EFF+ lambs, the EFF- lambs had a higher NEFA level,probably reflecting a greater use of energy reserves. This study shows a marked but relatively transient effect ofearly experience on behaviour, performance and metabolism in ewe lambs. Our results so far indicate little impactof genetic line alone or in interaction with experience., Le type d’élevage des agneaux dans le jeune âge peut impacter fortement leurs performances et leur capacitéd’adaptation à des challenges. La sélection génétique pour augmenter l’efficience est une voie pour favoriserl’adaptation à des milieux contraignants. Cette étude vise à étudier les effets respectifs et en interaction del’expérience précoce (allaitement artificiel (AA) vs maternel (AM)) et de la lignée génétique pour l’efficiencealimentaire (plus efficiente (EFF+) vs moins efficiente (EFF-)), pour 80 agnelles de race Romane dans un systèmeen plein air intégral sur parcours. Les agnelles AM sont élevées sur parcours avec les mères dès la naissance etsevrées à J90. Les agnelles AA sont élevées en bergerie, sevrées à J40 et maintenues en bâtiment jusqu’à J100.De J100 à J200, les agnelles AA et AM sont conduites en lots séparés sur le parcours. Des pesées régulières etdes prises de sang permettent de suivre la croissance et l’évolution de certains métabolites sur une période de 6mois (J0 à J200). L’activité comportementale a également été observée. Sur les 3 semaines suivant l’entrée sur leparcours, la croissance des AA est très inférieure à celle des AM et un écart de poids significatif subsiste 3,5 moisplus tard. Lors de l’entrée sur le parcours, les AA ont montré une activité d’alimentation beaucoup plus faible et untemps d’exploration plus élevé que les AM. Après 10 semaines de pâturage, ces différences d’activités sontfortement atténuées. La lignée génétique n’a pas d’impact sur l’activité comportementale ni sur la croissanceexcepté une tendance pour une croissance plus faible des EFF- entre J90 et J200. Après 3 semaines sur leparcours dans les mêmes conditions, les AA ont un métabolisme orienté vers la mobilisation des réserves avec unniveau d’AGNE supérieur aux AM à J120 et J135 et une glycémie inférieure à J135. Leur concentration en urée estinférieure aux mêmes dates, suggérant l’ingestion d’un régime moins riche en azote que les AM. Concernant lalignée génétique, à J120 et J135, la lignée EFF- présente un plus fort niveau d’AGNE indiquant une plus fortemobilisation des réserves chez ces agnelles. Cette étude montre un effet marqué de l’expérience précoce sur lecomportement, les performances et le métabolisme chez les agnelles, mais relativement transitoire. Nos résultatsindiquent pour l’instant peu d’impact de la lignée génétique, seule ou en interaction avec l’expérience.

In ruminants, feed efficiency is a complex trait involving the host and its ruminal microbiota. In meat sheep, little is known about their joint action on animal efficiency. The objective of this work was to explore the ruminal and plasmatic metabolome differences between genetically divergent lines on residual feed intake (RFI). Rumen and blood samples were taken from male lambs belonging to the two divergent lines selected on RFI estimated under a 100% concentrate diet. Samples were taken twice: firstly when lambs were around 3 month-old and fed the same diet as their ancestors did during selection and secondly when lambs were 7-9 month-old and fed a diet with 1/3 concentrate and 2/3 dactylis hay. Rumen samples were taken using an oesophageal probe and blood samples were taken at the jugular vein before being centrifuged to separate plasma from blood cells. All the samples were frozen. Preparation of the samples consisted in several centrifugations and addition of a phosphate buffer. Samples were then analysed using NMR spectrometry and integrated with the ASICS R package. Data was then analysed both using a mixed linear model using the sasLM R packageand multivariate analysis using mixOmics R package (PLS and PLS-DA). Because of the great effect of diet, concentrate and forage based data must be separately analysed. Rumen samples did not present many differences between lines under the concentrate diet and under the forage diet, no metabolite was differently expressed. Multivariate analysis on rumen samples did not separate the two lines well. On the contrary, plasma samples showed interesting differences between the 2 lines with amino acids being (under both diets) more present in plasma samples from less efficient animalsthan in samples from efficient ones. In both diets, plasma samples from efficient lambs had significantly (P

The SMARTER (SMAll RuminanT breeding for Efficiency and Resilience) H2020 project aims to develop and implement innovative strategies to improve resilience and efficiency (R&E) related traits in sheep and goats. Regarding feed efficiency, the objective is to identify novel traits that would be relevant, easy to measure and cheap enough to be collected in many animals to identify the most efficient individuals. In practice, feed efficiency can be assessed by different criteria such as residual feed intake and feed conversion ratio. Both criteria require feed intake to be measured for each individual which remains an expensive trait to get and hardly feasible under farm conditions. Thus, our objective is to identify novel traits related to feed efficiency and use them as proxies for feed intake and/or feed efficiency. First, novel phenotypes are identified and studied in experimental farms where feed intakes of concentrate and forage are recorded for each animal. Different novel phenotypes are being considered to study feed efficiency in sheep and goats, including (i) biomarkers (from blood or milk metabolomics), (ii) differentially expressed genes in targeted tissues, (iii) genomic polymorphisms, (iv) ruminal microbiota, (v) faecal NIR spectra, (vi) greenhouse gas emissions and body composition traits. These novel traits will be recorded either under classical feeding or under nutritional restriction to quantify, for example, the impact of a shortage of concentrate inputs. Then, the most promising novel traits will be measured in commercial populations. From these larger datasets, we will estimate heritabilities of the novel traits and genetic correlations to other traits in the breeding goal. Finally, for some case studies, we will quantify GxE interactions, particularly by considering the same breed under different breeding systems or regions.

Greenhouse gas (GHG) emissions by livestock largely contribute to global warming. In ruminants, eructed CH4 and CO2 are mainly the results of the ruminal microbiota activity. In small ruminants, GHG emissions have already been measured with different technologies such as SF6 gas tracers and both fixed and portable accumulation chambers. The INRAE P3R Experimental unit has been equipped with two sheep Greenfeed. The objective of this study was to define a phenotyping protocol and to analyse the recorded GHG emissions. We analysed a group of 34 Romane male lambs (with average body weight of 67.43 ±8.87 kg) bred in one pen equipped with one sheep Greenfeed. At each visit, GHG emissions are measured, but to be retained as a confident value, the sheep must stay at least two minutes with the nose placed close to the nose position sensor. Therefore, over 6 weeks of control, about 25% of the visits were confident enough and values were automatically retained in the dataset. This corresponded to an average of 3.92 visits with GHG values per animal per day. Visits were not equally distributed along the day: they depended on the frequency of distribution of concentrate and on the availability of device (dominance relationship among animals). Similarly to what had been observed in cattle, GHG emissions vary along the day with less emissions occurring before the meal. Therefore, because of the distribution of the visits and because of the variability of the GHG emissions along the day we had to correct raw emissions with these effects in a linear model : animal LS means were finally retrieved and considered as the animal emissions. In this group of 34 individuals, average CH4 and CO2 emissions were of 41.22 ± 4.52 g/d and 1254.92 ± 100.53 g/d respectively. This fitted an average of 0.67±0.08 g CH4 per day per kg of body weight. The correlation between CH4 and CO2 was high (0.80). GHG emissions were also positively correlated with the body weight and average daily gain, in agreement with the literature.

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International audience; The ruminal microbiota plays a central role in the nutrition of its host. Significant links between the rumen bacteria abundances and host performances (growth or feed efficiency) have been demonstrated in cattle, but few is known in sheep. Residual feed intake (RFI) is commonly used as a criterion to improve feed efficiency. At the INRAE P3R, divergent lines on RFI are being developed in the Romane meat sheep breed: individuals belong either to the RFI+ (inefficient) or RFI-(efficient) line. We proposed to investigate the ruminal population (bacteria, archaea, protozoa and fungi) of 277 lambs belonging to the 2 nd (in 2018) or 3 rd (in 2019 and 2020) generations of RFI selection. A first rumen fluid sample (C-sample) was taken at 4-5 months of age, after 6 weeks of feed efficiency control under a concentrate diet. Then, 167 out of these lambs were tested during 6 weeks under a forage-based diet (2/3 forage + 1/3 concentrate), after which a second sample of rumen fluid was taken (F-sample). During each of the 2 periods of control, feed intake, body weights and body composition traits were recorded. After DNA amplification, the ruminal microbiota was analysed by sequencing the 16s rRNA gene for bacteria and archaea, and the 18s rRNA gene for protozoa and fungi. Sequences were analysed with the FROGS pipeline to obtain relative abundances of OTUs (in proportion of total sequences per sample) which were then labelled according to phylum, family and genus levels. Due to the huge impact of diet type, C-samples and F-samples were considered separately in the statistical analyses. After a CLR transformation of the OTUs abundances to consider their compositional nature, ANOVAs were performed with a covariate, the age at sampling and the fixed effects of the year, the pen and the sequencing depth. Finally, discriminant analyses such as sPLS-DA (with MixOmics R package) were performed with the divergent line as the discriminant factor. As expected, more OTUs were identified in F-samples than in C-samples. Differences in the composition of the ruminal microbiota were highlighted between divergent lines under the different diets.

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Additional file 3: Figure S2. Total additive ( $${a}_{0}+{a}_{1}$$ a 0 + a 1 ) variance for daily feed intake (DFI) for different probabilities of the occurrence of an environmental challenge. Figure S3. Level ( $${a}_{0}$$ a 0 ) variance for daily feed intake (DFI) for different probabilities of the occurrence of an environmental challenge. Figure S4. Environmental sensitivity ( $${a}_{1}$$ a 1 ), variance for daily feed intake (DFI) for different probabilities of the occurrence of an environmental challenge. In all cases $$p$$ p is the environmental descriptor with $$p$$ p = 0 indicating non-challenging environmental conditions and $$p$$ p = 1 indicating highly challenging conditions. The interquartile range is shown in grey in all cases.

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Additional file 1: Table S1. Parameter estimates obtained using the reaction norm animal model (RNAM) with homogeneous residual variance (column in grey) and heterogeneous residual variances (last nine columns). One residual variance was set for normal days and one for highly variable days. Nine values of p, going from 0.10 to 0.90 were set as cutting points to differentiate between normal days and highly variable days.

Additional file 2: Figure S1. Heritability estimates for daily feed intake (DFI) for different probabilities of the occurrence of an environmental challenge ( $$p$$ p is the environmental descriptor with $$p$$ p = 0 indicating non-challenging environmental conditions and $$p$$ p = 1 indicating highly challenging conditions). The interquartile range is shown in grey.

International audience; Genetic selection focused purely on production traits has proven very successful in improving the productive performance of livestock. However, heightened environmental and infectious disease challenges have raised the need to also improve the resilience of animals to such external stressors, as well as their efficiency in utilising available resources. A better understanding of the relationship between efficiency and production and health traits is needed to properly account for it in breeding programmes and to produce animals that can maintain high production performance in a range of environmental conditions with minimal environmental footprint. The aim of this study was to perform a meta-analysis of genetic parameters for production, efficiency and health traits in sheep and goats. The dataset comprised 963 estimates of heritability and 572 genetic correlations collated from 162 published studies. A threelevel meta-analysis model was fitted. Pooled heritability estimates for milk production traits ranged between 0.27 ± 0.03 and 0.48 ± 0.13 in dairy goats and between 0.21 ± 0.06 and 0.33 ± 0.07 in dairy sheep. In meat sheep, the heritability of efficiency traits ranged from 0.09 ± 0.02 (prolificacy) up to 0.32 ± 0.14 (residual feed intake). For health traits, pooled heritability was 0.07 ± 0.01 (faecal egg count) and 0.21 ± 0.01 (somatic cell score) in dairy goats and 0.14 ± 0.04 (faecal egg count) and 0.13 ± 0.02 (somatic cell score) in dairy sheep. In meat sheep, the heritability of disease resistance and survival traits ranged between 0.07 ± 0.02 (mastitis) and 0.50 ± 0.10 (breech strike). Pooled estimates of genetic correlations between resilience and efficiency traits in dairy goats were not significantly different from zero with the exception of somatic cell score and fat content (À0.19 ± 0.01). In dairy sheep, only the unfavourable genetic correlation between somatic cell score and protein content (0.12 ± 0.03) was statistically significant. In meat sheep only, the correlations between growth and faecal egg count (À0.28 ± 0.11) as well as between growth and dagginess (À0.33 ± 0.13) were statistically significant and favourable. Results of this metaanalysis provide evidence of genetic antagonism between production and health in dairy sheep and goats. This was not observed in meat sheep where most of the pooled estimates had high standard errors and were non-significant. Based on the obtained results, it seems feasible to simultaneously improve efficiency and health in addition to production by including the different types of traits in the breeding goal. However, a better understanding of potential trade-offs between these traits would be beneficial. Particularly, more studies focused on reproduction and resilience traits linked to the animal's multitrait response to challenges are required.

García Baccino, Carolina Andrea. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina. - Université de Toulouse. GenPhySE. INRAE, ENVT. Tolosan, France. Etancelin, Christel Marie. Université de Toulouse. GenPhySE. INRAE, ENVT. Tolosan, France. Tortereau, Flavie. Université de Toulouse. GenPhySE. INRAE, ENVT. Tolosan, France. Marcon, Didier. Unité Expérimentale INRAE, Domaine de La Sapinière, INRAE. France. Weisbecker, Jean Louis. Université de Toulouse. GenPhySE. INRAE, ENVT. Tolosan, France. Legarra, Andres. Université de Toulouse. GenPhySE. INRAE, ENVT. Tolosan, France. Background: Resilient animals can remain productive under different environmental conditions. Rearing in increas - ingly heterogeneous environmental conditions increases the need of selecting resilient animals. Detection of environmental challenges that affect an entire population can provide a unique opportunity to select animals that are more resilient to these events.\nThe objective of this study was two-fold: (1) to present a simple and practical data-driven approach to estimate the probability that, at a given date, an unrecorded environmental challenge occurred; and (2) to evaluate the genetic determinism of resilience to such events.\nMethods: Our method consists of inferring the existence of highly variable days (indicator of environmental challenges) via mixture models applied to frequently recorded phenotypic measures and then using the inferred probabilities of the occurrence of an environmental challenge in a reaction norm model to evaluate the genetic determinism of resilience to these events.\nThese probabilities are estimated for each day (or other time frame). We illustrate the method by using an ovine dataset with daily feed intake (DFI) records.\nResults: Using the proposed method, we estimated the probability of the occurrence of an unrecorded environmental challenge, which proved to be informative and useful for inclusion as a covariate in a reaction norm animal model.\nWe estimated the breeding values for sensitivity of the genetic potential for DFI of animals to environmental challenges.\nThe level and slope of the reaction norm were negatively correlated (−0.46±0.21).\nConclusions: Our method is promising and appears to be viable to identify unrecorded events of environmental challenges, which is useful when selecting resilient animals and only productive data are available. It can be generalized to a wide variety of phenotypic records from different species and used with large datasets.\nThe negative correlation between level and slope indicates that a hypothetical selection for increased DFI may not be optimal depending on the presence or absence of stress. We observed a reranking of individuals along the environmental gradient and low genetic correlations between extreme environmental conditions. These results confirm the existence of a G×E\ninteraction and show that the best animals in one environmental condition are not the best in another one. grafs.

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AdaptMap Consortium.

International audience; In the light of an increasing demand for robustness, functional longevity appears to be an interesting criterion to study in addition to the current main selection criteria for French suckling sheep (prolificacy and mothering qualities). This study aims at characterizing genetic and non-genetic effects on functional longevity for French suckling ewes. Functional longevity is approached through length of productive life, using linear models as well as survival analysis methods. Analysis are undertaken on two representative French breeds (one specialized meat breed and a hardy meat breed), using data from the national performance recording system. Linear models are applied on the 62,410 Ile-de-France and 93,679 Blanches du Massif Central ewes born between 1990 and 2004 (uncensored careers). Survival analysis focuses on ewes born after 1990 from a known ram. Main significantly influencing non-genetic factors (P

International audience; Accurate pedigree information is an essential tool in genetic breeding programs to ensure the highest rate of genetic gain and allows management of inbreeding. However, the proportion of known sires can be very low in Spanish meat sheep populations, particularly in breeds reared in high mountain areas as in the Pyrenees. Single nucleotide polymorphisms (SNPs) are now the DNA markers of choice for parentage assignment. The objective of this study was to develop a SNP assay to use in some North-Eastern Spanish meat sheep populations for accurate pedigree assignment. Nine sheep breeds were sampled: Rasa aragonesa (n=38), Navarra (n=39), Ansotana (n=41), Xisqueta (n=41), Churra Tensina (n=38), Maellana (39), Roya bilbilitana (n=24), Ojinegra (n=36) and Cartera (n=39). We used SNP genotypes from the Illumina OvineSNP50 BeadChip array. Firstly, we selected the 249 SNPs published from the French panel for parentage assignment due to the high values of the Minor Allele Frequency (MAF) reported in the South-West European breeds. In total, 159 SNPs in Hardy-Weinberg equilibrium, displaying a MAF>0.3 and a call rate>0.97 in all the nine populations, and not associated with Mendelian errors in verified family trios or duos were selected. The average MAF was 0.43, ranging from 0.41 (Churra Tensina) to 0.44 (Xisqueta and Navarra). The probability (PI) that two randomly selected individuals having identical genotypes within breed was very low: it reached its lowest and highest value in the Cartera (8.81×10-67) and the Roya bilbilitana populations (2.29×10-64), respectively. The exclusion probabilities of either one or the two randomly selected parent(s) were close to 1 in all populations. The parentage assignment procedure was tested using KASP technology for genotyping in a final panel of 192 SNPs that included 159 SNPs for parentage assignment and 33 functional SNPs (PrnP, BMP15, MTNR1A…).

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International audience; The aim of this study was to explore the ruminal microbiota of lambs genetically extreme for their feeding speed when eating concentrates. From a database of 1001 lambs phenotyped for their feeding behavior, we estimated breeding values for their feeding speed at the visit level, and selected amongst 77 lambs phenotyped, 20 extreme lambs : 10 “high feeding speed” lambs with an average value of 57.8 g/min and 10 “low feeding speed” lambs with an average value of 26.8 g/min. The ruminal microbiota of these animals was profiled – after a first period of concentrates diets then a second period of forage – based diets - using 16S rRNA gene sequencing were analysed with FROGS software leading to 228 OTUs with taxonomic affiliation and characterized by their relative abundances. Microbiota differences was mainly due to the type of feed ingested-with higher bacteroidetes abundances when lambs ingested concentrates-since 211 of the 228 OTUs have abundance differences with respect of diet. Only 6 OTUs were significantly different according to feeding speed of animal and concerned only minor bacterial taxa such as bacteroidales S24_7 group family and the genus Syntrophococcus, Lachnosporacaeae NC2004 group, Ruminiclostridium and Eubacterium cellulosolvens group.

International audience; The improvement of lambing conditions with more autonomous ewes and vigorous lambs is of major importance for meat sheep breeders. During two years, Mouton Vendéen and Rouge de l’Ouest lambs have been weighed at birth (BW) and scored for assistance at birth and sucking as well as their level of activity. Heritability estimates for these three scores corresponded closely between the two breeds. Direct and maternal heritabilities were moderate to high, indicating that genetic selection would improve lamb vigour traits in both breeds. Moreover, genetic correlations between vigour traits were significant and positive. However, with the available dataset, we could not evidence any genetic correlation between lamb mortality and vigour scores.

Mutations in MC1R. Mutations found in MC1R region in Noire du Velay, Romanov and Suffolk sheep. (PDF 187Â kb)

Principal component analysis. PCA using 500Â K SNP genotypes of all French breeds in this study except MĂŠrinos de Rambouillet and Ouessant sheep. (PDF 19Â kb)

PCR and sequencing primers for sequencing MC1R gene. (PDF 185Â kb)

La sélection d’animaux efficaces est un enjeu majeur pour les filières animales, que ce soit pour des raisons économiques, mais aussi agro-environnementales. En effet, sélectionner des animaux efficaces permet de limiter les quantités ingérées et les émissions de polluants (gaz à effet de serre et résidus azotés). Chez les ovins allaitants, nous avons montré que la consommation résiduelle (CR) est un critère de sélection héritable (h²=0,41) corrélé génétiquement à la quantité de concentré ingérée par jour (rg=+0,73). La mise en place de lignées divergentes sur la CR (mesurée avec une alimentation concentrée) en race Romane permet 1) de mieux comprendre les mécanismes biologiques impliqués dans l’efficacité alimentaire et 2) d’évaluer les conséquences de la sélection génétique de ce critère d’efficacité alimentaire sur une diversité d’autres caractères (croissance, engraissement, développement musculaire, …) mais aussi lorsque les animaux ont une ration fourragère. Après deux générations de sélection, la divergence est marquée puisqu’elle s’élève à 1,9 écart-type génétique. Nous avons montré que les animaux efficaces (CR-) avec une ration concentrée mangent également moins de fourrage (103 g en moins par jour par animal) que les animaux peu efficaces (CR+) tout en ayant des niveaux de croissance équivalents. Des différences significatives entre CR- et CR+ se retrouvent au niveau du microbiote ruminal, Selecting efficient animals is a major concern for livestock production, not only for economic but also for agro-environmental purposes. The selection of efficient animals leads to a decrease of feed intakes and limits pollutant emissions (greenhouse gases and nitrogen). In meat sheep, we demonstrated that Residual Feed Intake (CR) is a heritable selection criteria (h²=0.41) which is genetically correlated to average daily feed intake (rg=+0.73) under a concentrated diet. We setup a divergent selection experiment on CR (under a concentrated diet) in the Romane breed in order to 1) have a better understanding of biological processes underlying feed efficiency and 2) to evaluate the consequences of the genetic divergence on feed efficiency over a panel of traits (growth, fattening, muscular development,…), also when animals are fed with forages. After two generations of selection, the divergence is marked since it reaches 1.9 genetic standard deviations. Efficient animals (CR-) under a concentrated diet also have a lower daily feed intake with a forage-based diet (103 g less) than less efficient animals (CR+) while displaying similar growth. Significant differences between CR- and CR+ animals were also described at the level of the rumen microbiota.

FLK results. FLK regions under selection, SNP frequencies, haplotype cluster frequencies and SNP and haplotype local trees. (PDF 14210Â kb)

F3 test results for migration events detected in the population tree estimated using treemix. (PDF 111Â kb)

International audience

International audience; The overall sustainability and innovative capacity of the sheep and goat sector in Europe have tobe improved to cope with current and future economic, environmental and societal challenges. Innovations ingenetic resource management and breeding for sheep and goat populations will be explored in the iSAGE Eu-ropean project (WP5) in order to help the industry to cope with such future challenges. In France, genetic eval-uation for small ruminants is performed in a large variability and poorly characterized environments. In this re-gard, we will consider multi-generation data from existing French breeding programs and experimental fieldstudies. Effects of herd for traits under genetic selection will be investigated in commercial farms in order tobetter characterize the production environment, particularly using meteorological data but also feeding, breed-ing system and economic criteria. Such characterization will enable to follow-up trends in animal performancesaccording to weather changes. This work could also contribute to characterize farm typologies to which a setof sustainability indicators will be tested. Then, contrasted environments will be identified and genotype by en-vironment interactions studies will be carried out aiming to improve genetic selection efficiency in a variety ofenvironments. In addition to existing data, we will explore new phenotypes considered as key functional traitsfor robustness and for which stakeholders are particularly interested. These new phenotypes will be also explored in combination with feed efficiency in experimental facilities under contrasted environments or under feedshortage challenges. Genetic and genomic studies will be performed for new phenotypes used to assess in-dividual robustness. The total merit indices will be revisited from the technical and economic point of view inorder to evaluate economic weights of each trait in the “breeding goal”, for diversified production systems.; En France, l’évaluation génétique des petits ruminants estime simultanément la valeur génétique des reproducteurs ainsi que les effets d’environnement dont le plus important est l’effet troupeau. Cette évaluation est réalisée dans des environnements variés et mal caractérisés faisant l’hypothèse d’absence d’interaction GxE. Pour tester cette hypothèse et disséquer les composantes des effets troupeaux, les environnements de production seront caractérisés à partir des données collectées en fermes (disponibles dans les systèmes nationaux d’information génétique ou collectées ponctuellement) décrivant les systèmes d’élevages et des données météorologiques. La discrimination des types d’environnements de production établis par la typologie des élevages permettra d’analyser les interactions GxE pour différentes races ovines et caprines en France. Par ailleurs, l’adaptation des petits ruminants à ces environnements variés et changeants implique entre autre leur efficacité d’utilisation des ressources et leur capacité biologique à mobiliser et reconstituer leurs réserves énergétiques sous forme de lipides. Des travaux expérimentaux seront conduits pour étudier les mécanismes biologiques et le déterminisme génétique de la dynamique des réserves corporelles en lien avec l’efficacité alimentaire. Cette approche permettra d’identifier de nouveaux phénotypes pour l’amélioration génétique de la robustesse des petits ruminants.

En France, l’évaluation génétique des petits ruminants estime simultanément la valeur génétique des reproducteurs ainsi que les effets d’environnement dont le plus important est l’effet troupeau. Cette évaluation est réalisée dans des environnements variés et mal caractérisés faisant l’hypothèse d’absence d’interaction GxE. Pour tester cette hypothèse et disséquer les composantes des effets troupeaux, les environnements de production seront caractérisés à partir des données collectées en fermes (disponibles dans les systèmes nationaux d’information génétique ou collectées ponctuellement) décrivant les systèmes d’élevages et des données météorologiques. La discrimination des types d’environnements de production établis par la typologie des élevages permettra d’analyser les interactions GxE pour différentes races ovines et caprines en France.Par ailleurs, l’adaptation des petits ruminants à ces environnements variés et changeants implique entre autre leur efficacité d’utilisation des ressources et leur capacité biologique à mobiliser et reconstituer leurs réserves énergétiques sous forme de lipides. Des travaux expérimentaux seront conduits pour étudier les mécanismes biologiques et le déterminisme génétique de la dynamique des réserves corporelles en lien avec l’efficacité alimentaire. Cette approche permettra d’identifier de nouveaux phénotypes pour l’amélioration génétique de la robustesse des petits ruminants., The overall sustainability and innovative capacity of the sheep and goat sector in Europe have to be improved to cope with current and future economic, environmental and societal challenges. Innovations in genetic resource management and breeding for sheep and goat populations will be explored in the iSAGE European project (WP5) in order to help the industry to cope with such future challenges. In France, genetic evaluation for small ruminants is performed in a large variability and poorly characterized environments. In this regard, we will consider multi-generation data from existing French breeding programs and experimental field studies. Effects of herd for traits under genetic selection will be investigated in commercial farms in order to better characterize the production environment, particularly using meteorological data but also feeding, breeding system and economic criteria. Such characterization will enable to follow-up trends in animal performances according to weather changes. This work could also contribute to characterize farm typologies to which a set of sustainability indicators will be tested. Then, contrasted environments will be identified and genotype by environment interactions studies will be carried out aiming to improve genetic selection efficiency in a variety of environments. In addition to existing data, we will explore new phenotypes considered as key functional traits for robustness and for which stakeholders are particularly interested. These new phenotypes will be also explored in combination with feed efficiency in experimental facilities under contrasted environments or under feed shortage challenges. Genetic and genomic studies will be performed for new phenotypes used to assess individual robustness. The total merit indices will be revisited from the technical and economic point of view in order to evaluate economic weights of each trait in the "breeding goal", for diversified production systems.

En France, la sélection des aptitudes bouchères est menée exclusivement en bergerie, que la sélection ait lieu sur performances individuelles ou sur descendance. L’utilisation de ce type de conduite en sélection est parfois remise en cause par les producteurs d’agneaux d’herbe doutant de la capacité des béliers sélectionnés en bergerie à être performants pour une production d’agneaux d’herbe. Pour vérifier cela, un essai mené à la ferme expérimentale de FEDATEST a permis de comparer les performances bouchères de deux lots d’agneaux issus de béliers sélectionnés selon le protocole du testage sur descendance : un lot conduit en bergerie et l’autre conduit à l’herbe. Huit béliers de race Rouge de l’Ouest ont été mobilisés pour réaliser deux lots d’IA en 2010 et huit autres mâles ont réalisé deux lots d’IA en 2012. En 2010, 379 inséminations réalisées en octobre – novembre ont permis d’obtenir 314 carcasses exploitables : 205 issues d’agneaux de bergerie et 109 d’agneaux menés à l’herbe. En 2012, 382 IA ont été mises en place, permettant l’exploitation de 175 carcasses d’agneaux de bergerie et 103 d’herbe. Pour atteindre un même poids vif d’abattage, les agneaux d’herbe ont dû être élevés en moyenne 8 jours de plus que les agneaux de bergerie. Sur des critères de conformation, rendement en carcasse et gras de couverture, les performances des agneaux élevés à l’herbe étaient inférieures à celles des agneaux élevés en bergerie. Sur la base des index semi-synthétiques conformation et gras estimés dans le cadre du testage boucher sur descendance, deux groupes de béliers ont été distingués : les « détériorateurs » et les « améliorateurs ». La comparaison des performances corrigées des descendants élevés à l’herbe et en bergerie a permis de démontrer que les meilleurs béliers pour la production d’agneaux de bergerie sont aussi les meilleurs pour la production d’agneaux d’herbe. En effet, les agneaux d’herbe issus de pères « améliorateurs » ont déposé moins de gras que ceux issus de pères « détériorateurs » avec des différences de moyennes statistiquement significatives de 0,3 mm de gras dorsal et 3 g de gras de rognon en moins. De même pour la conformation des agneaux menés à l’herbe, un tiers de classe EUROP sépare les performances des descendants issus de pères « améliorateurs » de ceux issus de pères « détériorateurs ». En conclusion, la production d’agneaux d’herbe, avec un niveau de performances satisfaisant, est possible à partir de béliers sélectionnés classiquement en bergerie sur performances propres et sur descendance.