title: Human-lamb bonding: oxytocin, cortisol and behavioural responses of lambs to human contacts and social separation.
abstract: 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.
authors.affiliation: INRA, UMRH1213 Herbivores, Site de Theix, 63122 Saint-Genès Champanelle, France. marjoriecoulon82@yahoo.fr
authors.forename: Marjorie
authors.initials: M
authors.lastname: Coulon
authors.forename: Raymond
authors.initials: R
authors.lastname: Nowak
authors.forename: Stéphane
authors.initials: S
authors.lastname: Andanson
authors.forename: Christine
authors.initials: C
authors.lastname: Ravel
authors.forename: Pierre Guy
authors.initials: PG
authors.lastname: Marnet
authors.forename: Alain
authors.initials: A
authors.lastname: Boissy
authors.forename: Xavier
authors.initials: X
authors.lastname: Boivin
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005260:Female; D001841:Human-Animal Bond; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D010121:Oxytocin / Q000097:blood*; D012756:Sheep / Q000097:blood* / Q000502:physiology* / Q000523:psychology; D012934:Social Isolation / Q000523:psychology*
chemical_list: D010121:Oxytocin; D006854:Hydrocortisone