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International audience; In sheep, the bond between the dam and her lambs is established during the first hours of a lamb's life. Genetic variability for behavioural reactivity of ewes assessed in an arena test performed 24 hr after lambing has already been reported. However, there is no evidence that this reactivity represents the ewe's maternal reactivity at lambing in outdoor conditions. The objective of this study was to investigate whether or not the behavioural reactivity of ewes in the arena test is genetically related to their maternal reactivity measured at lambing. A total of 935 Romane ewes were studied. The maternal reactivity of ewes at the outdoor lambing site was recorded in response to a human approach and to the handling of the lambs. Their behavioural reactivity was also recorded 24 hr post-lambing in the arena test that involved a separation from the litter and a human presence. Flight distance, aggressive reaction, time to restore contact with the litter, maternal behaviour scores and vocalizations recorded at the lambing site were heritable (0.12-0.34). All of these behaviours were genetically correlated with the behavioural reactivity in the arena test. The highest genetic correlations (from 0.60 to 0.90) were found amongst maternal behavioural scores, flight distance and high-pitched bleats. In conclusion, behavioural reactivity in the arena test can be used to assess early maternal reactivity in standardized conditions. Phenotyping of ewes' behavioural reactivity with a simplified arena test can be performed for genetic improvement in maternal behaviour in sheep.

Among the adaptive capacities of animals, the management of energetic body reserves (BR) through the BR mobilization and accretion processes (BR dynamics, BRD) has become an increasingly valuable attribute for livestock sustainability, allowing animals to cope with more variable environments. BRD has previously been reported to be heritable in ruminants. In the present study, we conducted genome-wide studies (GWAS) in sheep to determine genetic variants associated with BRD. BR levels and BR changes over time were obtained through body condition score measurements at eight physiological stages throughout each productive cycle in Romane ewes (n=1034) and were used as phenotypes for GWAS. After quality controls and imputation, 48,513 single nucleotide polymorphisms (SNP) were included in the GWAS. Among the QTLs identified, a major QTL associated with BR levels during pregnancy and lactation was identified on chromosome 1. In this region, several significant SNPs mapped to the leptin receptor gene (LEPR), among which one SNP mapped to the coding sequence. The point mutation induces the p.P1019S substitution in the cytoplasmic domain, close to tyrosine phosphorylation sites. The frequency of the SNP associated with increased BR levels was 32%, and the LEPR genotype explained up to 5% of the variance of the trait. These results provide strong evidence for involvement of LEPR in the regulation of BRD in sheep and highlight it as a major candidate for improving adaptive capacities.

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International audience; Breeding for resilience requires a better understanding of intra-flock variability and the related mechanisms responsible for robustness traits. Among such traits, the animals’ ability to cope with feed fluctuations by mobilizing or restoring body reserves (BR) is a key mechanism in ruminants. The objective of this work was to characterize individual variability in BR dynamics in productive Romane ewes reared in extensive conditions. The BR dynamics profiles were characterized by combining individual longitudinal measurements of BW and body condition scores (BCS) over several production cycles. Historical data, including up to 2628 records per trait distributed in 1146 ewes, underwent cluster analysis. Two to four trajectories were observed for BW depending on the cycle, while three trajectories were found for BCS, whatever the cycle. Most trajectories suggested that BR dynamics were similar but the level of BR may differ between ewes. Nevertheless, some trajectories suggested that both BR dynamics and levels were different for a proportion of ewes. Clustering on BW and BCS profiles adjusted for individual level trends, resulted in differences only in the level of BW or BCS, rather than differences in trajectories. Thus, the overall shape of trajectories was not changed considering or not the individual level trend across cycles. In addition to individual variability, the ewe’s age at first lambing and litter size contributed to the distribution of the ewes between the trajectories. Regarding the entire productive life, three trajectories were observed for BW and BCS changes over three productive cycles. Increase in BW at each cycle suggested that ewes kept growing up until 3 to 4 years old in our conditions. Similar alternation of BCS gains and losses across cycles suggested BR dynamics might be repeatable. Many individual trajectories remained the same throughout a ewe’s life, whatever the age at first lambing, parity or litter size. Our results demonstrate the relevance of using BW and BCS changes for characterizing the diversity of BR mobilization–accretion profiles in sheep in a long timespan perspective.

Animal robustness may be defined as a complex trait characterizing the ability of an individual to be adapted, productive and healthy under contrasted and fluctuating environmental situations. Such a trait is now considered an essential criterion in order to meet the more ambitious goals of farming sustainability. In ruminants, one of the key mechanisms via which robustness is expressed is the capacity to mobilize or restore body reserves (BR) to cope with the challenges of negative energy balances. The objectives of this work were as follows: 1) to estimate the genetic parameters related to BR dynamics in ewes over successive production cycles and 2) to investigate BR management relationships between different physiological stages. For this, historical individual BW and BCS data from 2,920 phenotyped ewes were used for genetic analysis. The changes in BW (∆BW) and BCS (∆BCS) over time were analyzed. Eight physiological stages were considered to investigate these changes over time: mating, early pregnancy, mid-pregnancy, lambing, early suckling, mid-suckling, weaning, and postweaning. The estimated heritability were low for both ∆BW (h2 = 0.13 to 0.18) and ∆BCS (h2 = 0.04 to 0.16). Moderate to high positive genetic correlations (from 0.48 to 0.91) were obtained between BR mobilization phases and between BR accretion phases. Similarly, moderate to high negative genetic correlations (from -0.36 to -0.75) were estimated between the BR mobilization and accretion periods, suggesting that mechanisms driving BR mobilization and accretion processes were genetically correlated. This is the first study in ruminants that demonstrate that the extent and temporal changes in profiles of BR mobilization and accretion are heritable and genetically linked, indicating that such traits could be considered in genetic programs aimed at improving robustness. Nevertheless, further research is needed for a more comprehensive understanding of BR dynamics, notably by including other physiological parameters (i.e., metabolites and hormones) and additional information on the productive and reproductive life of the ewe.

In livestock, improving maternal reactivity towards the litter is an important issue in breeding strategies to promote production and animal welfare. As of yet, no studies have investigated the within-breed genetic variation of maternal reactivity in sheep. The objective of this study was to estimate the genetic parameters of maternal reac-tivity traits. A total of 1,095 primiparous and 1,441 multiparous Romane ewes were phenotyped 24hr postlambing using a behavioural test (arena test, AT) over a 10-year experimental period. The test consisted of three successive phases evaluating the ewe's attraction to her litter, reactivity to separation from her litter, and reactivity to a conflict between attraction to her litter and avoidance of a motionless human. The ewes were reared exclusively on rangelands (South of France) and lambed outdoors in the spring. High-pitched bleating and low-pitched bleating in the AT were mostly highly heritable (0.39‒0.46). Heritabilities were moderate for proximity to the litter in the presence of a human (0.27) and low for locomotion and vigilance in the AT (0.09‒0.15). The measurements of a given behaviour in the three phases of the AT were highly genetically correlated. Few genetic correlations were found between the different behavioural traits in the AT, the highest correlations being between high-pitched bleating and low-pitched bleating (−0.43 to −0.77). In conclusion, our find-ings demonstrate moderate-to-high heritability for maternal reactivity traits. These traits could be included in genetic selection schemes to enhance maternal attachment provided there is no unfavourable link with other production traits.

The main objective of this work was to study the relationships between body reserve (BR) dynamics and rearing performance (PERF) traits in ewes from a Romane meat sheep flock managed extensively on “Causse” rangelands in the south of France. Flock records were used to generate data sets covering 14 lambing years (YR). The data set included 1,146 ewes with 2 ages of first lambing (AGE), 3 parities (PAR), and 4 litter sizes (LS). Repeated measurements of the BW and BCS were used as indicators of BR. The ewe PERF traits recorded were indirect measurements for maternal abilities and included prolificacy, litter weight and lamb BW at lambing and weaning, ADG at 1, 2, and 3 mo after lambing, and litter survival from lambing to weaning. The effects of different BW and BCS trajectories (e.g., changes in BW and BCS across the production cycle), previously been characterized in the same animals, on PERF traits were investigated. Such trajectories reflected different profiles at the intraflock level in the dynamics of BR mobilization–accretion cycles. Genetic relationships between BR and PERF traits were assessed. All the fixed variables considered (i.e., YR, AGE, PAR, LS, and SEX ratio of the litter) have significant effects on the PERF traits. Similarly, BW trajectories had an effect on the PERF traits across the 3 PARs studied, particularly during the first cycle (PAR 1). The BCS trajectories only affected prolificacy, lamb BW at birth, and litter survival. Most of the PERF traits considered here showed moderate heritabilities (0.17–0.23) except for prolificacy, the lamb growth rate during the third month and litter survival which showed very low heritabilities. With exception of litter survival and prolificacy, ewe PERF traits were genetically, strongly, and positively correlated with BW whatever the physiological stage. A few weak genetic correlations were found between BCS and PERF traits. As illustrated by BW and BCS changes over time, favorable genetic correlations were found, even if few and moderate, between BR accretion or mobilization and PERF traits, particularly for prolificacy and litter weight at birth. In conclusion, our results show significant relationships between BR dynamics and PERF traits in ewes, which could be considered in future sheep selection programs aiming to improve robustness.

In sheep, social reactivity and reactivity to humans are relevant behavioral responses that are used to investigate the behavioral adaptation of farm animals to various rearing conditions. Such traits were previously reported as heritable and associated with several QTLs. However, few behavior-related genotype by environment (G × E) interactions have been reported to date. The experiment was performed on 2,989 male and female lambs issued from 30 sires. Every sire had progeny reared under both intensive and extensive conditions. After weaning, all lambs were individually exposed to two standardized behavioral tests. A broad range of behaviors including vocalizations, locomotion, localization, vigilance, and flight distance were assessed. Two complementary statistic approaches, with and without assumptions on the biological significance of behaviors, were performed to investigate social reactivity and reactivity to humans. G × E interactions were investigated based on the genetic correlations estimated for each factor or trait between farming conditions; those significantly different from 1 indicating a G × E. Environmental effects showed that social reactivity and reactivity to humans were higher in intensively reared lambs. The heritability of factors or traits used to measure social reactivity and reactivity to humans was similar in both rearing conditions. Estimated heritabilities were high for vocalizations in response to social isolation, moderate for locomotion and vigilance in response to social isolation, and low for both flight distance to an approaching human and proximity to a motionless human. No significant G × E interaction was found for vocalizations. G × E interactions were found for locomotion, vigilance and flight distance. Genetic correlations between both environments were low to moderate for vigilance, locomotion and flight distance. Vocalization in response to social isolation with or without human presence was identified as a robust trait and could be used to improve sheep sociability, independently of the environment. A G × E interaction was observed for behavioral reactivity to humans. Although moderate, the genetic correlation for this trait between intensive and extensive conditions could be used to select sires in the same environment by taking into account the G × E and to produce in different environments progenies that are less reactive to humans.

Polyethylene glycol (PEG) measured with NIRS is known to be a valuable faecal marker when used in indoor experiments. In order to verify whether it can be used at pasture, an experiment was conducted with two trials. In trial 1, six Romane breed adult dry ewes placed in metabolism cages were fed daily with natural, freshly cut rangeland from a fertilised or unfertilised paddock for 6 weeks. Three ewes did not receive PEG and the three others were dosed with 10 g of PEG in solution form once daily until the end of the experiment to measure in vivo dry matter digestibility and PEG recovery rate for each forage quality. At the same time (trial 2), 15 ewe lambs and 14 lactating adult ewes suckling one or two lambs were allowed to graze together on the same herbage as that cut for indoor ewes. All animals were initially equipped with faecal bags emptied twice daily for collecting total faeces, and eight ewe lambs and seven adults were dosed once daily with 10 g of PEG. Faecal grab samples were collected for 4 to 5 days for each forage quality grazed. Indoor trial 1 showed that PEG had no effect on dry matter intake (DMI) or on digestibility. PEG recovery rates measured on fertilised (77.7%) and unfertilised (82.1%) forage were not different ( P>0.05). PEG recovery rates measured at pasture did not differ( P>0.05) between pasture quality and animal type with an average value of 68.9%. Faecal output measured with bags or estimated with PEG and calculated DMI were not different ( P>0.05) when PEG recovery rate measured at pasture was used. Conversely, using indoor PEG recovery values, significantly ( P

Background Current trends in sheep farming practices rely on animals with a greater level of behavioral autonomy than before, a phenotype that actively contributes to the sustainability of animal production. Social reactivity and reactivity to humans are relevant behavioral traits in sheep, known for their strong gregariousness and weak tolerance to handling, which have previously been reported with moderate to high heritabilities. To identify loci underlying such behaviors, we performed a genome study in Romane lambs. Results The experiment was carried out on 934 male and female lambs allocated into 9 half-sib families (average of 103 lambs per family) and reared outside. After weaning, all the lambs were individually exposed to 4 standardized behavioral tests combining social isolation, exposure to humans or handling, confinement and novelty (i.e. arena test, corridor test, isolation box test, shearing test). A broad range of behaviors including vocalizations, locomotion, vigilance and flight distance, as well as the cortisol response to handling, were collected. All lambs were genotyped using the Illumina OvineSNP50 BeadChip. QTL detection was performed by linkage, association and joint linkage and association analyses using the QTLmap software. Five main QTL regions were identified on sheep chromosomes (Ovis Aries Region, OAR) 12, 16, 19, 21 and 23 among many other QTLs with small to moderate effects. The QTLs on OAR12, 16 and 21 showed significant associations with social reactivity. The QTLs on OAR19 and 23 were found to be associated with reactivity to humans. No overlapping QTLs were identified for the different traits measured in the behavioral tests, supporting the hypothesis that different genetic factors influence social reactivity and tolerance to humans. Conclusion The results of this study using ovine SNP data suggest that in domestic sheep the behavioral responses to social separation and exposure to humans are under polygenic influence. The most relevant QTLs reported in the present study contain interesting candidate genes previously described to be associated with various emotional and social behaviors in mammals. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-778) contains supplementary material, which is available to authorized users.

International audience; The Romane sheep breed proved to be adapted to harsh conditions with high prolificacy and lamb survival in outdoor farming, even under bad climate conditions. This breed shows large variability in its fleece type at birth and it has been suggested that lamb survival could be related to birthcoat type. The aim of the present study was to: i) characterize the coat of the lamb at birth and quantify lamb survival in relation to the birthcoat type and its protective properties concerning heat loss in the Romane breed raised under permanent exposure outdoors from birth, and ii) estimate genetic parameters of birthcoat type in relation to lamb survival and live body weight. A total of 7,880 lambs from 104 sires and 1,664 dams were used in a 14-yr experiment. The pedigree file included 9,625 individuals over 15 generations. Birthcoat type, coat surface temperature, coat depth, lamb survival, and growth were measured from birth to weaning. Weather data (temperature, wind speed, relative humidity, and precipitation) were recorded daily during lambing time. Two types of coats were observed at birth: hairy coat (62.9% of lambs) with a long coat depth (average 23.3 mm) or woolly 1 (37.1% of lambs) with a short coat depth (average 8.3 mm). Birthcoat type was an important factor affecting lamb survival and growth from birth in the Romane breed. Total mortality rate was significantly less in hairy-bearing coat lambs than in short-woolly coat ones: 7.0% vs. 9.6%, 11.6 % vs. 14.8%, and 15.7 % vs. 20.1 % at 2, 10, and 50 d, respectively, and the relative risks of death increased by 37%, 67%, and 46 % at 2, 10, and 50 d of age, respectively, in short-woolly lambs. At birth, a significant lower coat surface temperature, indicating less heat loss, was observed in long-hairy coat lambs compared with others (21.1°C vs. 26.1°C). Heavier body weights and better growth performances up to the age of 50 d were observed in long-hairy-bearing coat lambs. Lamb survival was positively correlated to weather conditions at lambing time in short-woolly lambs, whereas no relation was observed in hairy-coat lambs. Heritability estimate of birthcoat type (hairy or woolly) is high (0.88). Genetic correlations between birthcoat type, lamb survival, and live body weight at birth were positive and moderate, suggesting that it would be beneficial to take birthcoat into account as an adaptive trait in any genetic strategies for sheep production in harsh conditions on rangelands.

International audience; Biomass production in grasslands, a key component of food provision for domestic herbivores, is known to depend on climate, resource availability, and on the functional characteristics of communities. However, the combined effects of these different factors remain largely unknown. The aim of the present study was to unravel the causes of variations in the standing biomass of plant communities using a long-term experiment conducted in a Mediterranean rangeland of Southern France. Two management regimes, sheep grazing and grazing associated with mineral fertilization, were applied to different areas of the study site over the past 25 years. Abiotic (temperature, available water, nutrients) and biotic (components of the functional structure communities) factors were considered to explain interannual and spatial variations in standing biomass in these rangelands. Standing biomass was highly predictable, with the best model explaining approximate to 80% of variations in the amount of biomass produced, but the variation explained by abiotic and biotic factors was dependent on the season and on the management regime. Abiotic factors were found to have comparable effects in both management regimes: The amount of biomass produced in the spring was limited by cold temperatures, while it was limited by water availability and high temperatures in the summer. In the fertilized community, the progressive change in the functional structure of the communities had significant effects on the amount of biomass produced: the dominance of few productive species which were functionally close led to higher peak standing biomass in spring.

We thank the technical staff of La Fage experimental farm for assisting with animal care and data collection, the technicians at the biochemistry laboratory Carlos Trives and Gaelle Rocco (UMR SELMET, Montpellier) for their work in plasma metabolites and hormones assays, Benoit Persyn (Agroclim Unit, INRA Domaine St Paul Site, Agroparc, Avignon) for providing us with the meteorologic data, and Philippe Hassoun (UMR SELMET) for the conserved feedstuffs chemical composition data. We also thank the 3 anonymous reviewers for their helpful comments and suggestions that contributed to the quality of the paper. This project was financially supported by a research grant of the Department of Animal Physiology and Animal Production Systems (Physiologie Animal et Systemes d'Elevage, PHASE) of INRA.; Throughout an entire year, 41 Romane ewes reared in an extensive rangeland were used to investigate temporal changes in body reserves (BRs) and profiles of related metabolites and metabolic hormones. Ewes were allocated to homogeneous groups according to BW and BCS and were distributed by parity (primiparous [PRIM], n = 21; multiparous [MULT], n = 20) and litter size (LSi; lambing singletons [SING], n = 21 or TWINS, n = 20). The feeding system was based on rotational grazing of rangeland paddocks and progressive supplementation with hay, silage, and barley at late pregnancy during the winter. Individual BW, BCS, plasma NEFA, beta-hydroxybutyrate (beta-OHB), glucose, insulin, leptin, and triiodothyronine (T-3) were monitored at -56, -12, 8, 49, 76, 107, 156, 195, 216, 246, and 301 d relative to lambing. The BR mobilization was observed from late pregnancy to the end of suckling and varied as a function of the ewe energy balance but also because of transitions from fertilized to native rangeland paddocks and by supplementation. Contrarily, BR accretion occurred from weaning, during the dry-off, and until the start of the next pregnancy. Lipolysis was well reflected by NEFA, beta-OHB, and T-3 kinetics. Mean BW (but not mean BCS) was affected by parity (MULT > PRIM), whereas both BW and BCS were influenced by LSi (SING > TWINS) but only for MULT. The most drastic BW loss was observed during the mid-suckling period (49 d in milk [DIM]) in all ewes. The lack of effects of LSi in PRIM but not in MULT was also evident in the majority of blood plasma kinetics, which were affected (P < 0.0001) by physiological stage in all ewes. A tendency to ketosis (beta-OHB) was found in ewes nursing TWINS around lambing, irrespective of parity. Glucose concentrations were greater during suckling and dry-off, and a peak (0.96 +/- 0.05 g/L) was attained at 156 DIM in MULT nursing TWINS. The highest plasma leptin concentration was observed during the start and the middle of the next pregnancy in MULT (107-216 DIM; 9.6 +/- 0.44 ng/mL). In all ewes the physiological stage affected T-3, which was affected by LSi just in MULT (from late pregnancy, MULT by SING > MULT by TWINS; 99.91 vs 85.52 ng/dL) and during suckling (111.7 +/- 4.18 ng/dL). Lamb BW was affected at birth and weaning by parity (MULT > PRIM) and LSi (SING > TWINS). Overall, temporal changes in BR were directly affected by the transition of physiological states and feeding levels, whereas individual responses were predetermined by parity. In MULT, the reactivity and magnitude of response was influenced by LSi. The whole set of parameters allowed us to detect sensitive and critical periods throughout the entire annual cycle. We thus identified opportunities for improved nutritional management, for example, during physiological states usually underestimated such as early and mid-pregnancy. This work indicates the applicability of long-term studies about BR dynamics in ruminants as a potential component contributing to farm economic resilience. (C) 2014 Elsevier Inc. All rights reserved.

Chantier qualité GA; International audience; The present study aimed to evaluate an experimental approach to individually assess social reactivity among sheep. INRA401 male lambs (n = 163) were reared together outdoors as part of a larger flock. Fifteen days after weaning the animals were individually exposed to an arena test of 2 phases (1-social attraction, 2-social isolation) during which proximity toward conspecifics and vocal and locomotor reactivity were measured. One day after the test their inter-individual distances were measured when grazing over a 2-h period in order to estimate their sociability on pasture. This was made using scan sampling recording the identity of the nearest neighbour for each individual, which led to the establishment of a sociability index. Overall, we found that high-pitched bleats recorded during the attraction phase (r = 0.22) and the isolation phase (r = 0.23) of the arena test as well as the locomo-tor activity measured during the isolation phase (r = 0.27) were positively correlated with the sociability index. Furthermore, the behaviour of lambs during the isolation phase of the arena test (i.e. vocal and locomotor agitation) appeared to be a significant predictor explaining 13% of the variance of the sociability on pasture. The behavioural reactivity measured through the arena test thus reflects at least to some extent the sociability of sheep. Those results are very encouraging as they suggest that the sociability of lambs could indeed be evaluated through a short experimental test, which is less time consuming than field ethological observations.

International audience; From the ancestral pelage of the domestic sheep which looks like the protective double coat of the wild sheep, changes following domestication and the development of textile industry resulted in the development of the modern woolled sheep with a large decrease in the tendency to moult and extension of wool fibre at the expense of coarse hair leading to a single coat where all fibres are similar in dimension and grow permanently. Wool production is still the main purpose of sheep farming in the southern hemisphere, but in Europe wool production is often unprofitable and there is an interest in the use of breeds that have no wool or shed their wool due to the relative value of meat and wool, and increasing shearing costs. In the present paper investigations were made to evaluate genetic variability of moulting or fleece shedding including QTL detection in the French Romane, the Martinik Hair, a hairy sheep without wool close to Barbados-Black-Belly and a Martinik Hair-Romane backcross population. In the Romane breed, 43.2% of adult ewes shed at least part of their fleece once a year during spring. Heritability estimate of moulting aptitude is high (0.46) but prevalence of total fleece shedding is low (1.5% of ewes shed all their fleece). In the Martinik Hair-Romane backcross population 72% of animals shed their fleece. It was proposed to introgress gene pool from the Martinik Hair in the Romane breed through an experimental design combining QTL detection and introgression of QTL for fleece shedding in the Romane breed.