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In this paper examinations of high-temperature wetting tests of 3 systems of liquid alloy – cast iron in contact with ceramic materials: magnesia ceramics in combination with natural graphite were presented. After wettability testing, the microscopic observations of the morphology of the sample surface and the cross-section microstructure with the chemical composition in micro-areas were examined. One of the objective of this work was also to verify whether the graphite content would affect the wettability of the magnesia ceramics. The study of high-temperature wetting kinetics of the liquid alloy in contact with the ceramic material, by the "sessile drop" method with capillary purification (CP) procedure was conducted. Under the test conditions, at a temperature of 1450°C and time 15 minutes, all 3 experimental systems showed a non-wetting behaviour. The average contact angle for the system with cast iron drop on magnesia ceramics was 140°, on magnesia ceramics with 10 parts per weight of graphite was 137° and on magnesia ceramics with 30 parts per weight of graphite - 139°. Microscopic observations revealed that in the case of the sample consisting of the cast iron drop on the substrate with magnesia ceramics, the formation of fine separations was not observed, unlike the systems with the substrate with magnesia ceramics and the addition of natural graphite. Numerous, fine droplets accumulate on the graphite flakes and consist mainly of Si as well as Fe and O. On the other hand, the rough MgO grains have a gray, matt surface, without fine separations. The conducted observations indicate the mechanical nature of the bonding - liquid metal penetrates into the pores of the rough ceramics of the substrate. However, in the case of systems of cast iron drop with magnesia ceramics and addition of graphite, probably the adhesive connection and the physical attraction of elements derived from cast iron drop with the flake graphite appeared as well.

Abstract Background The heterogeneous oceanographic conditions of continental shelf ecosystems result in a three-dimensionally patchy distribution of prey available to upper-trophic level predators. The association of bio-physical conditions with movement patterns of large marine predators has been demonstrated in diverse taxa. However, obtaining subsurface data that are spatio-temporally relevant to the decisions made by benthically-foraging species can be challenging. Methods Between 2009 and 2015, grey seals were captured on Sable Island, Nova Scotia, Canada during summer and fall and instrumented with high-resolution archival GPS tags. These tags recorded location data as well as depth (m), temperature (°C), and light level measurements during dives, until animals returned to the haulout site to breed. Hidden Markov models were used to predict apparent foraging along movement tracks for 79 individuals (59 females, 20 males) every 3 h. In situ measurements were used to estimate chlorophyll-a concentration (mg m− 3) and temperature within the upper-water column (50 m) and temperature and depth at the bottom of dives. As chlorophyll-a could only be estimated from 10:00 to 14:00 AST for dive depths ≥50 m, we formulated two generalized linear mixed-effects models to test the association of predicted grey seal behavioural states with oceanographic conditions and phytoplankton biomass: the first representing conditions of the upper-water column likely to influence primary productivity, and a second model including environmental conditions encountered by grey seals at the bottom of dives, when seals were more likely to be foraging. Results Predicted grey seal behavioural states were associated with fine-scale chlorophyll-a concentrations and other environmental conditions they encountered across the continental shelf. In the Water Column Model, season had no influence on the probability of observing apparent foraging, but chlorophyll-a, upper-water column temperature, and sex did, with females having a greater probability of foraging than males. In the Bottom Conditions Model, again season had no influence on the probability of apparent foraging, but females were over twice as likely as males to be foraging. Conclusions The results of this study highlight the value of in situ measurements of oceanographic properties that can be collected at high temporal resolution by animal-borne data loggers. These data provide insight into how inferred behavioural decisions made by large marine predators, such as the grey seal, may be influenced by fine-scale oceanographic conditions.

Although sheep are known to be seasonal breeders and give birth in winter, not all of them follow this trend. A few breeds can be mated and give birth all year round, meaning that mothers and neonates will have to face contrasting climatic conditions. The aim of this study was to test whether lambing season affects maternal and neonatal behaviors in D’man sheep. During four different lambing seasons (winter, autumn, summer and spring), periparturient ewes (n = 111) and their lambs (n = 213) were kept under 24-h-video surveillance in order to record postpartum behaviors. Mother-young preference was tested around 48 h after parturition. Lamb vigor was studied by the determination of birth weight, early postnatal behavior and rectal temperature at birth and 48 h later. Litter expulsion time was not affected by lambing season, but birth weight was biased against summer and winter born lambs. Ewes provided a higher intensity of care to their offspring in winter: latency for grooming was shorter and time spent grooming was longer compared to lambing in spring and summer (P = 0.01 in all cases). On the other hand, lambs were the most active in spring as they were faster to extend their hind legs (P = 0.01), stand up (P = 0.04) and reach the udder (P = 0.04). Rectal temperature at 48 h was affected by season of birth (P < 0.001) with higher values observed in summer. Glycemia variation between birth and 48 h was the lowest in spring born lambs and plasma levels increased less in spring born lambs than in winter (P < 0.0001), autumn (P < 0.0001) and summer born lambs (P < 0.0001). In the choice test, mothers clearly preferred their own young and no season effect was detected except that in the first minute of the test they spent less time near their own young in winter than in the other seasons (P = 0.04). Lambs also chose their mother successfully without any major effect of the season however, but winter born lambs were the least vocal (P = 0.01). Overall, this study show that maternal care, lamb behavior and vigor vary lightly according to seasons, albeit not in a consistent manner. In conclusion, a season is no more detrimental than another for the onset of mother-young relationships.

The common practice of artificially rearing lambs from prolific meat breeds of sheep constitutes a welfare issue due to increased mortality rates and negative health issues. In this multidisciplinary study, we investigated the possible short- and mid-term advantages of artificially feeding fresh ewe's milk instead of commercial milk replacer on lambs' growth, health and welfare. Romane lambs were either separated from their mothers on D3 and fed with Lacaune ewes' milk (LAC, n = 13) or milk replacer (REP, n = 15), or they were reared by their mothers (MOT, n = 15). On D45, they were weaned, gathered in single-sex groups until the end of the study on D150. Lamb performance and biomarkers of overall health were assessed by measuring: growth, dirtiness of the perianal area, enteric pathogens in the faeces, total antioxidant status and redox status assessed by plasma reduced glutathione/oxidised glutathione ratio, and immune response after vaccination against chlamydiosis. As an exploratory approach, blood cell transcriptomic profiles were also investigated. Last, qualitative behaviour assessment (QBA) was performed as an integrated welfare criterion. Lacaune ewes' milk and REP never differed in their average daily gain but grew less than MOT lambs in the early suckling period and just after weaning. No effect was detected afterwards. On D30, LAC and REP lambs had lower total antioxidant and higher redox status than MOT lambs but did not differ among themselves. Lacaune ewes' milk and MOT had a cleaner perianal area than REP lambs on D21, while faecal pathogen infection did not vary between the treatment groups. After vaccination, LAC also had a stronger immune response on D90 compared to REP lambs. Transcriptome analysis performed on D150 showed differential gene expression, mainly in relation to inflammatory, immune and cell cycle response, between male lambs of the LAC group and those of the MOT and REP groups. Based on QBA, LAC lambs never differed from MOT lambs in their general activity and varied from REP only on D21; REP lambs were always more agitated than MOT lambs. In conclusion, artificial milk feeding impaired early growth rate, health and emotional state mainly during the milk feeding period and at weaning. Feeding artificially reared lambs with fresh ewe's milk partly mitigated some of the negative effects induced by milk replacer but without achieving the full benefit of being reared by the mother.

Currently, a trend toward the commercialization of dromedary milk associated with recent intensive rearing systems has starting worldwide which impose constraints on animals affecting their behavioral repertoires and welfare status. The aim of this study was to investigate the effects of dam parity and calf sex on parturition, neonatal, and maternal behaviors in stabled Maghrebi dairy camels (Camelus dromedarius). Thirty-six (primiparas N = 10; multiparas N = 26) periparturient females were kept under video surveillance using a digital IR camera and 24-h sessions were chosen to assess calving, maternal, and neonatal behaviors in calving pens. Duration of restlessness, process of giving birth, and expulsion of fetal membranes were assessed. After first suckling, dams and their calves were moved into an individual enclosure to assess maternal behavior at 12 h, 24 h, 48 h, 72 h, and 7d postpartum. Behavior was assessed using a camcorder for 30 min after 1 h of young separation in an adjacent enclosure. Results showed an effect of parity on the duration of the birth process which was longer for primiparous than multiparous camels (P = 0.034). During this stage, primiparous females tended to raise their tails more often (P = 0.054) and spent more time standing (P = 0.001) than multiparous camels. Neonatal behavior was affected by calf sex. Female newborns took less time to raise their heads (P = 0.041) and to stand up (P = 0.048) for the first time and were the earliest to suckle their dams (P = 0.032). Multiparous dams stood up sooner (P = 0.019) after calving and suckled their calves earlier (P = 0.043) than primiparous dams. They emitted more bleats and exhibited more sniffing during the first week postpartum than primiparas. During the first postpartum week, both primiparas and multiparas showed a decrease in the total number of bleats (P

Hsp70 chaperones interact with substrate proteins in a coordinated fashion that is regulated by nucleotides and enhanced by assisting cochaperones. There are numerous homologues and isoforms of Hsp70 that participate in a wide variety of cellular functions. This diversity can facilitate adaption or specialization based on particular biological activity and location within the cell. In this review, we highlight two specialized binding partner proteins, Tim44 and IRE1, that interact with Hsp70 at the membrane in order to serve their respective roles in protein translocation and unfolded protein response signalling. Recent mechanistic data suggest analogy in the way the two Hsp70 homologues (BiP and mtHsp70) can bind and release from IRE1 and Tim44 upon substrate engagement. These shared mechanistic features may underlie how Hsp70 interacts with specialized binding partners and may extend our understanding of the mechanistic repertoire that Hsp70 chaperones possess.

Controlled drug delivery is a matter of interest to numerous scientists from various domains, as well as an essential issue for society as a whole. In the treatment of many diseases, it is crucial to control the dosing of a drug for a long time and thus maintain its optimal concentration in the tissue. Heart diseases are particularly important in this aspect. One such disease is an obstructive arterial disease affecting millions of people around the world. In recent years, stents and balloon catheters have reached a significant position in the treatment of this condition. Balloon catheters are also successfully used to manage tear ducts, paranasal sinuses, or salivary glands disorders. Modern technology is continually striving to improve the results of previous generations of stents and balloon catheters by refining their design, structure, and constituent materials. These advances result in the development of both successive models of drug-eluting stents (DES) and drug-eluting balloons (DEB). This paper presents milestones in the development of DES and DEB, which are a significant option in the treatment of coronary artery diseases. This report reviews the works related to achievements in construction designs and materials, as well as preparation technologies, of DES and DEB. Special attention was paid to the polymeric biodegradable materials used in the production of the above-mentioned devices. Information was also collected on the various methods of producing drug release coatings and their effectiveness in releasing the active substance.

The endoplasmic reticulum (ER) is an important site for protein folding and maturation in eukaryotes. The cellular requirement to synthesize proteins within the ER is matched by its folding capacity. However, the physiological demands or aberrations in folding may result in an imbalance which can lead to the accumulation of misfolded protein, also known as “ER stress.” The unfolded protein response (UPR) is a cell-signaling system that readjusts ER folding capacity to restore protein homeostasis. The key UPR signal activator, IRE1, responds to stress by propagating the UPR signal from the ER to the cytosol. Here, we discuss the structural and molecular basis of IRE1 stress signaling, with particular focus on novel mechanistic advances. We draw a comparison between the recently proposed allosteric model for UPR induction and the role of Hsp70 during polypeptide import to the mitochondrial matrix.

Neonatal mortality in small ruminant livestock has remained stubbornly unchanging over the past 40 years, and represents a significant loss of farm income, contributes to wastage and affects animal welfare. Scientific knowledge about the biology of neonatal adaptation after birth has been accumulating but does not appear to have had an impact in improving survival. In this paper, we ask what might be the reasons for the lack of impact of the scientific studies of lamb and kid mortality, and suggest strategies to move forward. Biologically, it is clear that achieving a good intake of colostrum, as soon as possible after birth, is crucial for neonatal survival. This provides fuel for thermoregulation, passive immunological protection and is involved in the development of attachment between the ewe and lamb. The behaviour of the lamb in finding the udder and sucking rapidly after birth is a key component in ensuring sufficient colostrum is ingested. In experimental studies, the main risk factors for lamb mortality are low birthweight, particularly owing to poor maternal nutrition during gestation, birth difficulty, litter size and genetics, which can all be partly attributed to their effect on the speed with which the lamb reaches the udder and sucks. Similarly, on commercial farms, low birthweight and issues with sucking were identified as important contributors to mortality. In epidemiological studies, management factors such as providing assistance with difficult births, were found to be more important than risk factors associated with housing. Social science studies suggest that farmers generally have a positive attitude to improving neonatal mortality but may differ in beliefs about how this can be achieved, with some farmers believing they had no control over early lamb mortality. Facilitative approaches, where farmers and advisors work together to develop neonatal survival strategies, have been shown to be effective in achieving management goals, such as optimising ewe nutrition, that lead to reductions in lamb mortality. We conclude that scientific research is providing useful information on the biology underpinning neonatal survival, such as optimal birthweights, lamb vigour and understanding the importance of sufficient colostrum intake, but the transfer of that knowledge would benefit from an improved understanding of the psychology of management change on farm. Developing tailored solutions, on the basis of adequate farm records, that make use of the now substantial body of scientific literature on neonatal mortality will help to achieve lower neonatal mortality.

The unfolded protein response (UPR) is a key signaling system that regulates protein homeostasis within the endoplasmic reticulum (ER). The primary step in UPR activation is the detection of misfolded proteins, the mechanism of which is unclear. We have previously suggested an allosteric mechanism for UPR induction (Carrara et al., 2015) based on qualitative pull-down assays. Here, we develop an in vitro Förster resonance energy transfer (FRET) UPR induction assay that quantifies IRE1 luminal domain and BiP association and dissociation upon addition of misfolded proteins. Using this technique, we reassess our previous observations and extend mechanistic insight to cover other general ER misfolded protein substrates and their folded native state. Moreover, we evaluate the key BiP substrate-binding domain mutant V461F. The new experimental approach significantly enhances the evidence suggesting an allosteric model for UPR induction upon ER stress.

Les ovins sont bien connus pour développer différentes formes d’attachement social. Le déclenchement de la motivation maternelle et le développement d’un lien mutuel entre la mère et son jeune sont sous l’influence combinée de stimulations hormonales et somato-sensorielles périphériques. Ces stimulations sont fournies par la parturition chez la mère et par les premiers épisodes de tétée chez le nouveau-né. Des changements neurophysiologiques profonds sont observés dans les bulbes olfactifs principaux de la brebis, alors qu’ils sont exposés à des odeurs d’agneau nouveau-né. L’activation de l’hypothalamus consécutive à la mise bas contribue à l’expression de la motivation maternelle et à la mémorisation des odeurs de l’agneau. L’hypothalamus et l’amygdale sont également activés chez le nouveau-né suite à l’ingestion de colostrum. L’ocytocine, un neuropeptide connu pour jouer un rôle clé dans les comportements prosociaux, facilite la construction de la relation mère-jeune. Lorsque des agneaux nouveau-nés sont séparés de leur mère pour être artificiellement nourris, une pratique agricole très commune, ils sont profondément affectés. Les réponses neuroendocrinologiques suggèrent que les agneaux sont dans une situation de détresse. Cependant, si un humain prend soin d’eux, une liaison interspécifique se met en place, facilitée par des contacts sociaux positifs dans lesquels l’allaitement au biberon ou les caresses jouent un rôle clé. De tels contacts activent le système ocytocinergique, comme cela est observé dans la construction du lien mère-jeune. Ainsi, dans des conditions d’élevage artificiel, l’être humain devient une figure d’attachement saillante qui se substitue à la mère et qui peut faciliter la gestion des agneaux.

Temperament influences the expression of maternal behaviour in sheep under experimental field conditions. We investigated whether maternal behaviour between ewes selected for a calm or nervous temperament is independent from environmental conditions. In addition, the level of maternal behaviour expressed by mothers is correlated with the concentration of hormones during the peripartum period. Therefore, we investigated whether the selection for temperament had resulted in hormonal differences between the two lines with regard to the hormones that could be involved in the onset of maternal behaviour. Oestradiol, progesterone and cortisol concentrations from 4 days before parturition to 24 h after parturition were determined from blood samples collected from 10 calm and 12 nervous ewes. Behavioural interactions between ewe and lamb were also recorded for 2 h starting at parturition. Mothers of both temperament lines showed adequate maternal behaviour under the controlled conditions of the study. Therefore, the results of the study do not suggest that selection for a calm or nervous temperament has profoundly affected the intrinsic ability of mothers to display adequate maternal behaviour. Hormonal differences between the two temperament lines were generally small and their possible influence on the display of maternal behaviour in the two temperament lines would have to be demonstrated.

Amniotic fluid (AF) is important for the establishment of maternal behaviour in inexperienced ewes, but its role in experienced mothers remains to be studied. Here, the maintenance of post-partum maternal responsiveness and the establishment of exclusive bonding was investigated in multiparous ewes when AF was removed from the neonate or/and physical contact with the young was precluded for the first 4 h post partum. Maintenance of maternal responsiveness and establishment of exclusive bonding were measured by the proportion of mothers accepting their own lamb and alien lambs that had been either washed or not washed, and by comparing an acceptance score for each type of lamb. The acceptance score was computed by summing standardised variables of acceptance (low bleats, acceptance at udder, nursing and licking time) and subtracting standardised variables of rejection (high-pitched bleats, rejection at the udder and aggressive behaviour). Washing the neonate reduced its acceptance score, but the proportion of mothers rejecting their own lamb was reduced only when washing the neonate and prevention of physical contact for 4 h were combined (7/15 v. 0/10 in controls, P = 0.02). In addition, washing the neonate increased the acceptance score of the washed alien lamb, but not of the unwashed alien. However, washing and privation of physical contact did not increase significantly the proportion of mothers accepting an alien lamb at 4 h post partum. We conclude that AF is important in experienced ewes for the establishment of maternal responsiveness, as already found in primiparous mothers. In addition, our results indicate that AF also carries some chemosensory information facilitating exclusive bonding.

The unfolded protein response (UPR) is an essential cell signaling system that detects the accumulation of misfolded proteins within the endoplasmic reticulum (ER) and initiates a cellular response in order to maintain homeostasis. How cells detect the accumulation of misfolded proteins remains unclear. In this study, we identify a noncanonical interaction between the ATPase domain of the ER chaperone BiP and the luminal domains of the UPR sensors Ire1 and Perk that dissociates when authentic ER unfolded protein CH1 binds to the canonical substrate binding domain of BiP. Unlike the interaction between chaperone and substrates, we found that the interaction between BiP and UPR sensors was unaffected by nucleotides. Thus, we discover that BiP is dual functional UPR sensor, sensing unfolded proteins by canonical binding to substrates and transducing this event to noncanonical, signaling interaction to Ire1 and Perk. Our observations implicate BiP as the key component for detecting ER stress and suggest an allosteric mechanism for UPR induction.

L’élevage des jeunes est une étape importante pour le succès reproductif des mammifères. La survie postnatale dépend de l’activation du comportement maternel et de l’orientation du comportement des nouveau-nés. Les déclencheurs du comportement maternel diffèrent entre les espèces, mais il existe certaines règles générales. Chez certaines espèces, les informations sensorielles fournies par les nouveau-nés suffisent à déclencher un comportement maternel immédiat, mais dans d’autres les facteurs endocriniens maternels et proprioceptifs liés à la parturition sont indispensables. L’aptitude des femelles à s’occuper d’un jeune est généralement améliorée par l’expérience maternelle. Dans toutes les espèces étudiées, la parturition représente une période sensible de réceptivité au nouveau-né accrue, y compris chez les Primates et l’espèce humaine. Les facteurs activateurs internes à la femelle peuvent aussi varier entre espèces. Cependant les estrogènes, la progestérone, l’expulsion du fœtus et la libération intracérébrale d’ocytocine qui l’accompagne, sont les facteurs le plus souvent retrouvés. Les structures nerveuses cibles sont principalement le complexe aire préoptique médiane/noyau de la strie terminale, le noyau paraventriculaire de l’hypothalamus, les bulbes olfactifs et l’amygdale. Enfin, dans la plupart des espèces dont les jeunes sont bien développés à la naissance, la mère apprend à reconnaître son nouveau-né en quelques heures, principalement à son odeur, et rejette alors tout jeune étranger à la mamelle. Cet apprentissage dépend du système olfactif principal et est facilité par le processus d’expulsion du fœtus. Il met également en jeu l’amygdale et plusieurs structures corticales. Quant au comportement du nouveau-né, il est guidé par un certain nombre d’informations sensorielles maternelles. La valeur de certaines de ces informations peut être déjà déterminée à la naissance (phéromone maternelle de la lapine) ou acquise par renforcement lors de la tétée (préférence pour la mère chez l’agneau). Il en résulte des interactions réciproques entre les la mère et son jeune, où chacun des membres de la dyade devient un facteur de contrôle du comportement de l’autre.

Les ruminants d’élevage appartiennent à des espèces grégaires. Leur organisation sociale est basée sur des relations stables de dominance - subordination qui assurent en élevage la résolution de nombreux conflits inhérents à la promiscuité entre les animaux. L’organisation sociale repose également sur des relations d’affinité qui assurent la cohésion du groupe et accroissent la tolérance entre les animaux dans les situations de conflit. En outre, les relations d’affinité participent étroitement à l’adaptation de l’animal à son milieu d’élevage puisque les partenaires influencent la réponse de l’animal aux éléments qui l’entourent. Tout au long de sa vie, l’animal établit des liens privilégiés avec certains de ses partenaires. Dès sa naissance, si la possibilité lui en est donnée, le jeune herbivore développe rapidement avec sa mère une relation préférentielle quasi-exclusive. Par la suite, même si le lien maternel demeure très fort, le jeune se lie également à d’autres membres du groupe, en particulier à sa fratrie ou à ses compagnons de même âge. Plus tard, la séparation maternelle qu’impose le sevrage réalisé par l’homme, exacerbe transitoirement la motivation sociale du jeune à l’égard de ses partenaires, voire à l’égard d’individus d’autres espèces tel l’homme. Une telle plasticité dans les comportements sociaux existe également chez l’animal adulte : en particulier, l’attraction sociale diminue chez la femelle pré-parturiente qui tend à s’isoler du troupeau dans la période de la mise bas. Une meilleure connaissance du comportement social des ruminants d’élevage doit permettre de proposer des aménagements pour mieux adapter la conduite d’élevage aux besoins sociaux des animaux. En outre, la construction dynamique des liens d’affinité laisse entrevoir certaines périodes clefs au cours de l’élevage comme autant de leviers d’action dont une meilleure exploitation en élevage pourrait faciliter l’intégration de l’animal à ses conditions de vie ultérieures. Ainsi, que ce soit par l’aménagement de conduites plus respectueuses des besoins sociaux des animaux ou par l’action sur les périodes de transition sociale, l’adaptation et le bien-être des animaux en élevage s’en trouveront considérablement accrus.

Chez les ruminants, le comportement maternel présente, immédiatement après la mise-bas, un certain nombre de traits communs comme la consommation des membranes et des liquides foetaux (les camélidés font exception), l’intérêt pour le nouveau-né et son léchage. Ces soins focalisent l’attention du nouveau-né vers le corps maternel et favorisent le succès des premières prises de colostrum. Après cette phase initiale qui dure quelques heures, les ruminants se subdivisent en deux groupes distincts : les espèces qui cachent leur nouveau-né pendant une durée variable (ex : cerf, chevreuil, caprins, bovins), et ceux dont le petit suit sa mère dès la naissance (ex : renne, ovins). La relation mère-jeune est, par ailleurs, caractérisée par une reconnaissance interindividuelle bien développée, base de la sélectivité maternelle : rapidement, la femelle n’accepte d’allaiter que son nouveau-né. La formation du lien mère-jeune s’effectue généralement sans problème. Toutefois, dans certaines conditions, le comportement maternel peut, par son absence ou sa sélectivité, devenir un facteur limitant la production.

L’odorat joue un rôle essentiel dans les communications entre les mammifères. La reconnaissance individuelle peut se faire sur la seule base de signaux olfactifs provenant de diverses sécrétions ou excrétions, même isolées. L’odeur d’un individu peut également informer sur son état émotionnel. L’organisation des différentes étapes du comportement sexuel met en oeuvre des odeurs venant du mâle comme de la femelle. Des signaux chimiques permettent d’identifier l’état d’oestrus de la femelle, mais celle-ci est alors très fortement attirée par l’odeur du mâle. Ces signaux interviennent dans le déclenchement des postures d’acceptation et de monte. Les odeurs sexuelles interviennent également dans la régulation physiologique : l’odeur du bélier induit l’ovulation de la brebis en repos sexuel, celle de la femelle en oestrus produit une sécrétion d’hormone gonadotrope et de testostérone chez le mâle. Les différentes phases de la relation de la mère et du jeune font appel aux communications olfactives. Chez la brebis, l’attraction pour le liquide amniotique produit le premier contact et le léchage du nouveau-né. L’odeur individuelle de l’agneau est à la base de la sélectivité de la relation maternelle, et c’est l’odorat qui guide l’agneau dans la première recherche de la mamelle. Cependant, dans tous les cas étudiés, l’odorat agit en interaction avec les autres canaux sensoriels, dans une action cumulative et souvent redondante.