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Nowak R.,CNRS Physiology of Reproduction and Behaviors | Nowak R.,University of Tours | Nowak R.,Institute Francais Du Cheval Et Of Lequitation | Boivin X.,French National Institute for Agricultural Research | Boivin X.,VetAgro Sup
Applied Animal Behaviour Science | Year: 2015

Animals develop relationships with intra- and interspecific partners, including humans. In some cases this can lead to strong emotional bonds indicating the existence of attachment. The sheep is well known to develop various forms of social attachment (mothers towards young, lambs towards siblings). The relationship they can develop with humans is much less understood. In this review, based on the attachment theory framework developed in human infants, we outline features and mechanisms that participate in the development and the expression of affiliative behaviours that lambs can develop with their mother or a human. Behavioural tests comparing responses towards a presumed attachment figure with those directed towards unfamiliar or familiar conspecifics demonstrate that lambs do search specifically the proximity of their mother or human caregiver. Differential emotional responses in the presence (calmness) or the absence of the partner (agitation) are also expressed. However, a relationship with a human takes place more easily when lambs are reared without their primary attachment figure, the mother. Human-lamb attachment is then facilitated by positive social contacts (gentling, hand-feeding) provided by a specific caregiver. In the case of attachment with the mother, suckling is the main reward. Although the existence of a sensitive period is still unclear, in both cases attachment develops more rapidly if positive interactions take place immediately after birth. Three neurochemical systems have profound impact on the expression of filial attachment in sheep: the gut peptide cholecystokinin, endogenous opioids, and oxytocin, all known to play a key role in prosocial behaviours in mammals. In addition, positive nutritive or non-nutritive interactions activate specific brain regions that are involved in the expression of social and emotional behaviours. In conclusion, lambs do develop intra- and interspecific attachment but not in a concomitant manner as the presence of the mother strongly reduces their motivation to interact with a human. Nonetheless, under artificial rearing conditions the human becomes a salient attachment figure. © 2014 Elsevier B.V.


Pirault P.,Agro ParisTech | Danvy S.,Institute Francais Du Cheval Et Of Lequitation | Verrier E.,Agro ParisTech | Verrier E.,French National Institute for Agricultural Research | And 2 more authors.
PLoS ONE | Year: 2013

Since horse breeds constitute populations submitted to variable and multiple outcrossing events, we analyzed the genetic structure and gene flows considering horses raised in France. We used genealogical data, with a reference population of 547,620 horses born in France between 2002 and 2011, grouped according to 55 breed origins. On average, individuals had 6.3 equivalent generations known. Considering different population levels, fixation index decreased from an overall species FIT of 1.37%, to an average F̄IS of -0.07% when considering the 55 origins, showing that most horse breeds constitute populations without genetic structure. We illustrate the complexity of gene flows existing among horse breeds, a few populations being closed to foreign influence, most, however, being submitted to various levels of introgression. In particular, Thoroughbred and Arab breeds are largely used as introgression sources, since those two populations explain together 26% of founder origins within the overall horse population. When compared with molecular data, breeds with a small level of coancestry also showed low genetic distance; the gene pool of the breeds was probably impacted by their reproducer exchanges. © 2013 Pirault et al.


Dardente H.,CNRS Physiology of Reproduction and Behaviors | Dardente H.,French National Center for Scientific Research | Dardente H.,University of Tours | Dardente H.,Institute Francais Du Cheval Et Of Lequitation | And 2 more authors.
Frontiers in Endocrinology | Year: 2014

Living organisms show seasonality in a wide array of functions such as reproduction, fattening, hibernation, and migration. At temperate latitudes, changes in photoperiod maintain the alignment of annual rhythms with predictable changes in the environment. The appropriate physiological response to changing photoperiod in mammals requires retinal detection of light and pineal secretion of melatonin, but extraretinal detection of light occurs in birds. A common mechanism across all vertebrates is that these photoperiod-regulated systems alter hypothalamic thyroid hormone (TH) conversion. Here, we review the evidence that a circadian clock within the pars tuberalis of the adenohypophysis links photoperiod decoding to local changes of TH signaling within the medio-basal hypothalamus (MBH) through a conserved thyrotropin/deiodinase axis. We also focus on recent findings which indicate that, beyond the photoperiodic control of its conversion, TH might also be involved in longer-term timing processes of seasonal programs. Finally, we examine the potential implication of kisspeptin and RFRP3, two RF-amide peptides expressed within the MBH, in seasonal rhythmicity. © 2014 Dardente, Hazlerigg and Ebling.


Coulon M.,French National Institute for Agricultural Research | Nowak R.,CNRS Physiology of Reproduction and Behaviors | Nowak R.,French National Center for Scientific Research | Nowak R.,University of Tours | And 7 more authors.
Psychoneuroendocrinology | Year: 2013

Friendly interactions between humans and animals such as gentling or petting have been shown to have positive behavioural and physiological consequences in many species. In primates, rodents and dogs, oxytocin has been associated with tactile contact and anti-stress effects that may influence bonding and responses to stress situations. However the activation of the oxytocinergic system in other human-animal interactions such as with herbivores, had not yet been studied. Sixteen female lambs were reared by artificial feeding reinforced with 3× 30. s daily stroking sessions. At 6 weeks of age, the test consisted in measuring first plasma oxytocin and cortisol responses in lambs during a first 6-min phase in the home pen where the familiar caregiver gently stroked the lamb, and then physiological and behavioural responses in a test pen during a 20-min - phase of social isolation followed by a 20-min - phase of reunion with its familiar caregiver. The lambs expressed behavioural agitation during the whole period of isolation. A strong affiliative response towards the human and a sustained reduction of the agitation behaviour were observed during reunion. Lambs' behaviours when isolated and when in contact with the human were correlated suggesting a response to social separation from the familiar caregiver more than to social isolation from congeners. No significant changes in cortisol levels were observed during the test. Oxytocin levels did not vary during human contact, but increased when the familiar caregiver left the lamb alone in the test pen. In conclusion, lambs displayed affiliative responses towards their caregiver, and the lack of cortisol response during isolation while oxytocin was released suggest an anti-stress effect of oxytocin. © 2012 Elsevier Ltd.


Pillet E.,CNRS Physiology of Reproduction and Behaviors | Pillet E.,French National Center for Scientific Research | Pillet E.,University of Tours | Duchamp G.,CNRS Physiology of Reproduction and Behaviors | And 8 more authors.
Theriogenology | Year: 2011

Hen egg yolk is normally used as a cryoprotective agent in semen freezing extenders, but its use has sanitary and practical disadvantages. Moreover the protection afforded by egg yolk has not yet been completely elucidated. The objective of this study was to compare the egg yolk plasma fraction to whole egg yolk in stallion freezing extender. Plasma contains mainly Low Density Lipoproteins (LDL), which are widely presumed to be the cryoprotective agent in egg yolk. Plasma can be produced on an industrial scale, sterilised by gamma-irradiation and incorporated in a ready-to-use extender (our ultimate objective). Plasma samples were subjected to different doses of gamma-irradiation (3, 5, 10 kGy) without dramatic chemical changes that may affect their cryoprotective properties. Stallion semen was frozen with whole egg yolk as a control and with sterilised egg yolk plasma. A fertility trial was conducted on a total of 70 mares' cycles. Fertility per cycle was 60% after insemination of semen frozen in our control extender containing egg yolk (EY), compared to 69% for the extender containing sterilised egg yolk plasma (EYP) (P > 0.05). Post-thaw motility and membrane integrity of spermatozoa were also analysed. Motility parameters were not significantly different between extenders except for the variable VAP (for EY versus EYP, VAP: 63 μm.s-1 versus 59 μm.s-1, a, b: P < 0.001; PROG: 41% versus 39%, RAP30: 56% versus 54%; RAP40: 51% versus 48%, P > 0.05). Membrane integrity was better preserved in EY than in EYP but the difference between extenders was small (P < 0.05). Our results demonstrated that sterilised egg yolk plasma has the potential to replace egg yolk in stallion freezing extender. This experiment led to the development of a ready-to-use extender called INRA-Freeze® (IMV-Technologies, France). © 2011 Elsevier Inc.

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