title: Valence of physical stimuli, not housing conditions, affects behaviour and frontal cortical brain activity in sheep.
abstract: Modulation of short-term emotions by long-term mood is little understood but relevant to understand the affective system and of importance in respect to animal welfare: a negative mood might taint experiences, whilst a positive mood might alleviate single negative events. To induce different mood states in sheep housing conditions were varied. Fourteen ewes were group-housed in an unpredictable, stimulus-poor and 15 ewes in a predictable, stimulus-rich environment. Sheep were tested individually for mood in a behavioural cognitive bias paradigm. Also, their reactions to three physical stimuli thought to differ in their perceived valence were observed (negative: pricking, intermediate: slight pressure, positive: kneading). General behaviour, activity, ear movements and positions, and haemodynamic changes in the cortical brain were recorded during stimulations. Generalised mixed-effects models and model probabilities based on the BIC (Bayesian information criterion) were used. Only weak evidence for mood difference was found. Sheep from the unpredictable, stimulus-poor housing condition had a somewhat more negative cognitive bias, showed slightly more aversive behaviour, were slightly more active and moved their ears somewhat more. Sheep most clearly differentiated the negative from the intermediate and positive stimulus in that they exhibited more aversive behaviour, less nibbling, were more active, showed more ear movements, more forward ear postures, fewer backward ear postures, and a stronger decrease in deoxyhaemoglobin when subjected to the negative stimulus. In conclusion, sheep reacted towards stimuli according to their presumed valence but their mood was not strongly influenced by housing conditions. Therefore, behavioural reactions and cortical brain activity towards the stimuli were hardly modulated by housing conditions.
authors.affiliation: Centre for Proper Housing of Ruminants and Pigs, Federal Food Safety and Veterinary Office FSVO, Agroscope, Institute for Livestock Sciences, Tänikon, CH-8356 Ettenhausen, Switzerland; Animal Behaviour, Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
authors.forename: Sabine
authors.initials: S
authors.lastname: Vögeli
authors.affiliation: Centre for Proper Housing of Ruminants and Pigs, Federal Food Safety and Veterinary Office FSVO, Agroscope, Institute for Livestock Sciences, Tänikon, CH-8356 Ettenhausen, Switzerland; Animal Behaviour, Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
authors.forename: Janika
authors.initials: J
authors.lastname: Lutz
authors.affiliation: Biomedical Optics Research Laboratory, Division of Neonatology, University Hospital Zurich, Frauenklinikstrasse 10, CH-8091 Zurich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Wolf
authors.affiliation: Centre for Proper Housing of Ruminants and Pigs, Federal Food Safety and Veterinary Office FSVO, Agroscope, Institute for Livestock Sciences, Tänikon, CH-8356 Ettenhausen, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Wechsler
authors.affiliation: Centre for Proper Housing of Ruminants and Pigs, Federal Food Safety and Veterinary Office FSVO, Agroscope, Institute for Livestock Sciences, Tänikon, CH-8356 Ettenhausen, Switzerland. Electronic address: lorenz.gygax@agroscope.admin.ch.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Gygax
mesh_terms: D000339:Affect / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001696:Biomechanical Phenomena; D002560:Cerebrovascular Circulation / Q000502:physiology; D004423:Ear / Q000502:physiology; D004644:Emotions / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply / Q000502:physiology*; D006799:Housing, Animal; D009043:Motor Activity / Q000502:physiology; D010812:Physical Stimulation; D011581:Psychological Tests; D011897:Random Allocation; D034561:Sheep, Domestic / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D055698:Touch Perception / Q000502:physiology
keywords: Cognitive bias; Ear movements; Emotion; Functional near-infrared spectroscopy (fNIRS); Mood