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International audience; Milk somatic cell count (SCC) is commonly higher in goats than in cattle and sheep. Furthermore, the ability of milk SCC to predict mastitis is considered lower in goats than in cattle and sheep, and the relevance of somatic cell score (SCS)-based selection in this species has been questioned. To address this issue, we created 2 divergent lines of Alpine goats using artificially inseminated bucks with extreme estimated breeding values for SCS. A total of 287 goats, 158 in high- and 129 in low-SCS lines, were scrutinized for mastitis infections. We subjected 2,688 milk samples to conventional bacteriological analyses on agarose and bacterial counts were estimated for positive samples. The SCS, milk yield, fat content, and protein content were recorded every 3 wk. Clinical mastitis was systematically noted. A subset of 40 goats (20 from each line) was subsequently challenged with Haemonchus contortus and monitored for anemia (blood packed cell volume) and fecal egg counts to see if SCS-based selection had an indirect effect on resistance to gastrointestinal nematodes. Milk production traits, including milk quantity, fat content, and protein content, were similar in both goat lines. In contrast, the raw milk SCC almost doubled between the lines, with 1,542,000 versus 855,000 cells/mL in the high- and low-SCS lines, respectively. The difference in breeding value for SCS between lines was 1.65 genetic standard deviation equivalents. The Staphylococcus spp. most frequently isolated from milk were S. xylosus, S. caprae, S. epidermidis, and S. aureus. The frequency of positive bacteriology samples was significantly higher in the high-SCS line (49%) than in the low-SCS line (33%). The highest odds ratio was 3.49 (95% confidence interval: 11.95-6.25) for S. aureus. The distribution of bacterial species in positive samples between lines was comparable. The average quantity of bacteria in positive samples was also significantly higher in high-SCS goats (69 ± 80 growing colonies) than in low-SCS goats (38 ± 62 growing colonies). Clinical cases were rare and equally distributed between high- (n = 4; 2.5%) and low-SCS (n = 3; 2.3%) lines. Furthermore, the larger the amounts of bacteria in milk the higher the SCS level. Conversely, goats with repeatedly culture-negative udders exhibited the lowest SCC levels, with an average of below 300,000 cells/mL. We therefore confirmed that SCS is a relevant predictor of intramammary infection and hygienic quality of milk in goats and can be used for prophylactic purposes. After challenge with H. contortus, goats were anemic with high fecal egg counts but we found no difference between the genetic lines. This result provides initial evidence that resistance to mastitis or to gastrointestinal nematodes infections is under independent genetic regulation. Altogether, this monitoring of the goat lines indicated that SCS-based selection helps to improve udder health by decreasing milk cell counts and reducing the incidence of infection and related bacterial shedding in milk. Selection for low SCC should not affect a goat's ability to cope with gastrointestinal nematodes.

Milk somatic cell count (SCC) is commonly higher in goats than in cattle and sheep. Furthermore, the ability of milk SCC to predict mastitis is considered lower in goats than in cattle and sheep, and the relevance of somatic cell score (SCS)-based selection in this species has been questioned. To address this issue, we created 2 divergent lines of Alpine goats using artificially inseminated bucks with extreme estimated breeding values for SCS. A total of 287 goats, 158 in high- and 129 in low-SCS lines, were scrutinized for mastitis infections. We subjected 2,688 milk samples to conventional bacteriological analyses on agarose and bacterial counts were estimated for positive samples. The SCS, milk yield, fat content, and protein content were recorded every 3 wk. Clinical mastitis was systematically noted. A subset of 40 goats (20 from each line) was subsequently challenged with Haemonchus contortus and monitored for anemia (blood packed cell volume) and fecal egg counts to see if SCS-based selection had an indirect effect on resistance to gastrointestinal nematodes. Milk production traits, including milk quantity, fat content, and protein content, were similar in both goat lines. In contrast, the raw milk SCC almost doubled between the lines, with 1,542,000 versus 855,000 cells/mL in the high- and low-SCS lines, respectively. The difference in breeding value for SCS between lines was 1.65 genetic standard deviation equivalents. The Staphylococcus spp. most frequently isolated from milk were S. xylosus, S. caprae, S. epidermidis, and S. aureus. The frequency of positive bacteriology samples was significantly higher in the high-SCS line (49%) than in the low-SCS line (33%). The highest odds ratio was 3.49 (95% confidence interval: 11.95-6.25) for S. aureus. The distribution of bacterial species in positive samples between lines was comparable. The average quantity of bacteria in positive samples was also significantly higher in high-SCS goats (69 ± 80 growing colonies) than in low-SCS goats (38 ± 62 growing colonies). Clinical cases were rare and equally distributed between high- (n = 4; 2.5%) and low-SCS (n = 3; 2.3%) lines. Furthermore, the larger the amounts of bacteria in milk the higher the SCS level. Conversely, goats with repeatedly culture-negative udders exhibited the lowest SCC levels, with an average of below 300,000 cells/mL. We therefore confirmed that SCS is a relevant predictor of intramammary infection and hygienic quality of milk in goats and can be used for prophylactic purposes. After challenge with H. contortus, goats were anemic with high fecal egg counts but we found no difference between the genetic lines. This result provides initial evidence that resistance to mastitis or to gastrointestinal nematodes infections is under independent genetic regulation. Altogether, this monitoring of the goat lines indicated that SCS-based selection helps to improve udder health by decreasing milk cell counts and reducing the incidence of infection and related bacterial shedding in milk. Selection for low SCC should not affect a goat's ability to cope with gastrointestinal nematodes.

The growing range of drug resistant parasitic nematode populations threatens the sustainability of ruminant farming worldwide. In this context, nutraceuticals, animal feed that provides necessary dietary requirements while ensuring parasite control, could contribute to increase farming sustainability in developed and low resource settings. In this study, we evaluated the anthelmintic potential of lupin seed extracts against the major ruminant trichostrongylids, Haemonchus contortus and Teladorsagia circumcincta. In vitro observations showed that seed extracts from commercially available lupin varieties could significantly but moderately inhibit larval migration. This anthelmintic effect was mediated by the seed alkaloid content and was potent against both fully susceptible and multidrug resistant H. contortus isolates as well as a susceptible T. circumcincta isolate. Analytical chemistry revealed a set of four lupanine and sparteine-derivatives with anthelmintic activity, and electrophysiology assays on recombinant nematode acetylcholine receptors suggested an antagonistic mode of action for lupin alkaloids. An in vivo trial in H. contortus infected lupin-fed ewes and goats failed to demonstrate any direct anthelmintic effect of crude lupin seeds but infected lupin-fed goats suffered significantly less parasite-mediated blood losses. Altogether, our findings suggest that the anthelmintic potential of lupin remains limited. However, the potent alkaloids identified could lead to the development of novel drugs or may be used in combination with current anthelmintics to improve their efficacy.

National audience

La maîtrise de la saisonnalité de la reproduction est un enjeu pour les filières ovines et caprines. De nouvelles approches pour induire et synchroniser les chaleurs et les ovulations hors saison sexuelle en alternative à l’utilisation d’hormones ou faisant appel à l’élevage de précision sont développées, tant pour l’agriculture conventionnelle (AC) que pour agriculture biologique (AB). Dans le projet REPROBIO, à partir d’enquêtes réalisées auprès d’intervenants en élevage et d’éleveurs ovins et caprins en AB et en AC, nous avons dressé un état des lieux des pratiques de gestion de la reproduction mises en œuvre dans les principaux bassins de production en France. Puis nous avons évalué l’acceptabilité par les acteurs de terrain de deux outils innovants associés à la gestion de la reproduction et développés dans le cadre des travaux de R&D du projet : i) l’utilisation de phéromones impliquées dans l’effet mâle (comme alternative aux traitements hormonaux pour l’induction et la synchronisation des ovulations et des chaleurs) et ii) la détection automatisée des chaleurs, pour optimiser la mise à la reproduction par insémination artificielle (IA) ou pour la lutte en main (détecteur électronique de chevauchements (Alpha-D®) chez la brebis et colliers-accéléromètres (Heatime®) chez la chèvre)., A major concern for small ruminant productions is to control the seasonality of the reproduction. Alternatives to hormonal treatment for the induction and the synchronization of oestrus or approaches based on precision livestock farming are developed both for conventional and organic farms. In the REPROBIO project, we established the current state of reproduction management practices implemented in the six French main production areas from surveys of farm holders and sheep and goat breeders under both conventional and organic farming. Then, we evaluated the acceptability of the actors for two innovative tools related to the reproduction management in farms, and developed in the frame of this R & D project: i) the use of pheromones involved in the male effect (an alternative to the hormonal treatment for induction and synchronization of oestrus) and ii) the automated oestrus detection, to optimize the mating time for artificial insemination (AI) or natural service (automated oestrus detector (Alpha-D®) for sheep, automated activity monitoring collars (Heatime®) for goat)

National audience

Staphylococcus aureus is the major cause of very severe mastitis of dairy goats. The initial objective of our study was to fine-tune an experimental model of infection of the goat mammary gland with two strains of S. aureus and two lines of goats (low and high somatic cell score lines). Following the challenge, the 10 infected goats divided in two clear-cut severity groups, independently of the S. aureus strain and the goat line. Five goats developed very severe mastitis (of which four were gangrenous) characterized by uncontrolled infection (UI group), whereas the other five kept the infection under control (CI group). The outcome of the infection was determined by 18 h post-infection (hpi), as heralded by the bacterial milk concentration at 18 hpi: more than 107/mL in the UI group, about 106/mL in the CI group. Leukocyte recruitment and composition did not differ between the groups, but the phagocytic killing at 18 hpi efficiency did. Contributing factors involved milk concentrations of α-toxin and LukMF' leukotoxin, but not early expression of the genes encoding the pentraxin PTX3, the cytokines IL-1α and IL-1β, and the chemokines IL-8 and CCL5. Concentrations of TNF-α, IFN-γ, IL-17A, and IL-22 rose sharply in the milk of UI goats when infection was out of control. The results indicate that defenses mobilized by the mammary gland at an early stage of infection were essential to prevent staphylococci from reaching critical concentrations. Staphylococcal exotoxin production appeared to be a consequent event inducing the evolution to gangrenous mastitis.

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018; A major concern for small ruminant productions is to control the seasonality of the reproduction.Alternatives to hormonal treatment for the induction and the synchronization of oestrus or approachesbased on precision livestock farming are developed both for conventional and organic farms. In the REPROBIO project, we established the current state of reproduction management practicesimplemented in the six French main production areas from surveys of farm holders and sheep and goatbreeders under both conventional and organic farming. Then, we evaluated the acceptability of theactors for two innovative tools related to the reproduction management in farms, and developed in theframe of this R & D project: i) the use of pheromones involved in the male effect (an alternative to thehormonal treatment for induction and synchronization of oestrus) and ii) the automated oestrusdetection, to optimize the mating time for artificial insemination (AI) or natural service (automatedoestrus detector (Alpha-D®) for sheep, automated activity monitoring collars (Heatime®) for goat); La maîtrise de la saisonnalité de la reproduction est un enjeu pour les filières ovines et caprines. Denouvelles approches pour induire et synchroniser les chaleurs et les ovulations hors saison sexuelle enalternative à l’utilisation d’hormones ou faisant appel à l’élevage de précision sont développées, tantpour l’agriculture conventionnelle (AC) que pour agriculture biologique (AB).Dans le projet REPROBIO, à partir d’enquêtes réalisées auprès d’intervenants en élevage et d’éleveursovins et caprins en AB et en AC, nous avons dressé un état des lieux des pratiques de gestion de lareproduction mises en œuvre dans les principaux bassins de production en France. Puis nous avonsévalué l’acceptabilité par les acteurs de terrain de deux outils innovants associés à la gestion de lareproduction et développés dans le cadre des travaux de R&D du projet : i) l’utilisation de phéromonesimpliquées dans l’effet mâle (comme alternative aux traitements hormonaux pour l’induction et lasynchronisation des ovulations et des chaleurs) et ii) la détection automatisée des chaleurs, pouroptimiser la mise à la reproduction par insémination artificielle (IA) ou pour la lutte en main (détecteurélectronique de chevauchements (Alpha-D®) chez la brebis et colliers-accéléromètres (Heatime®) chezla chèvre).

Dans les troupeaux ovins allaitants, l’allaitement artificiel strict avec un lait reconstitué est fréquemment utilisé pour sauver des agneaux surnuméraires mais peut entrainer des performances décevantes. L’objectif de cette étude est d’évaluer, chez des agneaux de race Romane, l’impact de ce mode d’élevage sur leurs performances et sur leurs réponses immunitaire et comportementale à court et moyen terme. Trois traitements d’allaitement sont comparés : agneaux maternés (un agneau par mère), agneaux mis en allaitement artificiel à 3 jours d’âge et nourris soit avec du lait commercial reconstitué ou avec du lait de brebis Lacaune traites quotidiennement. Au sevrage à 45 jours, les agneaux des différents traitements ont été réallotés par sexe et alimentés avec du foin et du concentré. Les agneaux nourris avec l’aliment d’allaitement ont une croissance avant 22 jours significativement plus faible que les agneaux maternés, ceux nourris au lait de brebis étant intermédiaires. Au-delà, il n’apparait plus de différence et le poids final est équivalent. Ces agneaux allaités artificiellement, quel que soit le lait, apparaissent plus actifs en case d’élevage et moins craintifs vis-à-vis de l’homme en situation de test à J21. Lorsqu’ils sont nourris avec l’aliment d’allaitement, l’aspect de leur arrière train a tendance à être plus sale que celui des agneaux nourris au lait de brebis sans pour autant qu’ils soient plus infectés par des pathogènes intestinaux. Le stress oxydant est plus faible chez les agneaux en allaitement artificiel, malgré un statut antioxydant global moins favorable, probablement en rapport avec leur meilleure familiarisation à l’homme lors des prélèvements. Par contre le lait de brebis Lacaune prépare mieux les agneaux au stress du sevrage. De même, la réponse immunitaire à une vaccination contre la chlamydiose est plus forte pour ce traitement. Dans les conditions de cette étude avec un faible taux de mortalité et un effectif d’agneaux limité, l’allaitement artificiel strict pénalise la croissance et le statut antioxydant et favorise la relation à l’homme uniquement dans la période d’allaitement. Les différences s’estompent rapidement après le sevrage., In sheep production, artificial rearing with commercial milk is frequently used to save lambs born from large litters but is usually connected with poor animal performance. The objective of this study was to estimate the impact of this rearing method on the performance of lambs from the Romane breed, but also their short and medium-term immune and behavioual responses. Lambs were assigned to three rearing treatments: left with the mother (one lamb per dam), or separated at 3 days of age and fed either with a commercial milk substitute or with milk from Lacaune ewes milked daily. When weaned at 45 days, the lambs of the three treatments were mixed, reared in single sex groups and fed with hay and concentrate. Lambs fed commercial milk had significantly lower growth rate before 22 days than mothered lambs, those fed Lacaune milk being intermediate. No difference was detectable later on and the final weight was similar. Artificially reared lambs, regardless of the type of milk, seemed more active in their rearing pens and less afraid of humans in tests performed at 21 days. The fleece around the perianal area of lambs fed commercial milk tended to be dirtier than in lambs fed with ewe’s milk without any increase on the presence of pathogens in the faeces. Consumption of artificial milk was associated with lower antioxidant status and higher level of stress at 30 days of age compared to mothered lambs. The immune response following vaccination against chlamydiosis was not different between lambs fed artificial milk and those nursed by their mother. In this study where mortality rate was low, artificial rearing was seen to impair growth rate and antioxidant status and to promote a lamb human relationship only during the artificial rearing period.

International audience; 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 x 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 x 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 x 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 x E interaction was found for vocalizations. G x 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 x 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 x E and to produce in different environments progenies that are less reactive to humans.

International audience

Nous cherchons à développer chez les caprins de nouveaux protocoles d’induction des ovulations pendant l’anoestrus saisonnier, associant effet mâle et traitements photopériodiques, et permettant une synchronisation des ovulations compatible avec l’utilisation de l’insémination artificielle. Dans ce cadre, nous avons étudié chez des chèvres de race Alpine les effets d’une supplémentation énergétique à court-terme (basée sur l’utilisation de propylène-glycol) sur le degré de synchronisation de la réponse ovulatoire après effet bouc. Les résultats observés, concernant à la fois le moment d’apparition du pic pré-ovulatoire de LH et la montée de progestéronémie après introduction des boucs, suggèrent i/ un avancement des ovulations induites par l’effet mâle au moment du cycle normal, et ii/ une plus grande synchronie de ces ovulations chez les chèvres supplémentées et présentant une réponse ovulatoire de type cycle court – cycle normal après effet mâle., We aim to develop new protocols for goats that associate the male effect and photoperiodic treatments to induce ovulations during the anoestrus season, and that also synchronize ovulations allowing the use of artificial insemination. Using Alpine goats, we studied the effects of a short-term dietary energy supplementation (based on propylene-glycol) on the synchronization of ovulations induced by bucks. The results concerning both the time of the pre-ovulatory LH peak and the time when plasma progesterone began to rise after buck introduction, suggest i/ that ovulations in normal cycles occur earlier and ii/ are better synchronized in supplemented goats presenting a “short cycle – normal cycle” response after the male effect.

National audience; We aim to develop new protocols for goats that associate the male effect and photoperiodic treatments to induce ovulations during the anoestrus season, and that also synchronize ovulations allowing the use of artificial insemination. Using Alpine goats, we studied the effects of a short-term dietary energy supplementation (based on propylene-glycol) on the synchronization of ovulations induced by bucks. The results concerning both the time of the pre-ovulatory LH peak and the time when plasma progesterone began to rise after buck introduction, suggest i/ that ovulations in normal cycles occur earlier and ii/ are better synchronized in supplemented goats presenting a “short cycle – normal cycle” response after the male effect.; Nous cherchons à développer chez les caprins de nouveaux protocoles d’induction des ovulations pendant l’anoestrus saisonnier, associant effet mâle et traitements photopériodiques, et permettant une synchronisation des ovulations compatible avec l’utilisation de l’insémination artificielle. Dans ce cadre, nous avons étudié chez des chèvres de race Alpine les effets d’une supplémentation énergétique à court-terme (basée sur l’utilisation de propylène-glycol) sur le degré de synchronisation de la réponse ovulatoire après effet bouc. Les résultats observés, concernant à la fois le moment d’apparition du pic pré-ovulatoire de LH et la montée de progestéronémie après introduction des boucs, suggèrent i/ un avancement des ovulations induites par l’effet mâle au moment du cycle normal, et ii/ une plus grande synchronie de ces ovulations chez les chèvres supplémentées et présentant une réponse ovulatoire de type cycle court – cycle normal après effet mâle.

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