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The Way Humans Behave Modulates the Emotional State of Piglets.

Brajon S, Laforest JP, Schmitt O, Devillers N - PLoS ONE (2015)

Bottom Line: Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray).The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10).However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Agriculture and Agri-Food Canada, Dairy and Swine Research and Development Centre, 2000 College Street, Sherbrooke, Quebec, J1M 0C8, Canada; Université Laval, Department of Animal Science, 2325 Rue de l'Université, Quebec city, Quebec, G1V 0A6, Canada.

ABSTRACT
The emotional state can influence decision-making under ambiguity. Cognitive bias tests (CBT) proved to be a promising indicator of the affective valence of animals in a context of farm animal welfare. Although it is well-known that humans can influence the intensity of fear and reactions of animals, research on cognitive bias often focusses on housing and management conditions and neglects the role of humans on emotional states of animals. The present study aimed at investigating whether humans can modulate the emotional state of weaned piglets. Fifty-four piglets received a chronic experience with humans: gentle (GEN), rough (ROU) or minimal contact (MIN). Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray). Independently of the treatment (P = 0.82), 59% of piglets completed the training. Successfully trained piglets were then subjected to CBT, including ambiguous cues in presence or absence of a human observer. As hypothesized, GEN piglets showed a positive judgement bias, as shown by their higher percentage of go responses following an ambiguous cue compared to ROU (P = 0.03) and MIN (P = 0.02) piglets, whereas ROU and MIN piglets did not differ (P > 0.10). The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10). However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001). This study originally demonstrates that the nature of a chronic experience with humans can induce a judgement bias indicating that the emotional state of farm animals such as piglets can be affected by the way humans interact with them.

No MeSH data available.


Related in: MedlinePlus

Overview of the testing arena and the apparatus.(A) Sketch of the testing arena viewed from the top, including the apparatus and the speakers; (B) Sketch of the apparatus viewed from the side, including the camera, the light, the plastic tube and the trough. In bold topography, a part of the material used for punishments, including the tennis ball relied on a fishing line, the air compressor relied on an air spray gun and a water spray gun; (C) Picture of the apparatus viewed from the front; (D) Picture of the apparatus viewed from the top with a piglet at the trough.
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pone.0133408.g001: Overview of the testing arena and the apparatus.(A) Sketch of the testing arena viewed from the top, including the apparatus and the speakers; (B) Sketch of the apparatus viewed from the side, including the camera, the light, the plastic tube and the trough. In bold topography, a part of the material used for punishments, including the tennis ball relied on a fishing line, the air compressor relied on an air spray gun and a water spray gun; (C) Picture of the apparatus viewed from the front; (D) Picture of the apparatus viewed from the top with a piglet at the trough.

Mentions: The testing arena was located in an experimental room separated from housing rooms and consisted of a 2.30 m2 arena made of plastic-coated expanded metal flooring with an apparatus on the narrow side (Fig 1). Two digital video cameras (Panasonic WV-CP 480, Panasonic, Mississauga, ON, Canada), one fixed above the apparatus, the other fixed above the testing arena, were used to record behaviour of piglets at 15 FPS and behaviour was analysed using a specialised recording and viewing software (Omnicast, Genetec Inc., Montréal, QC, Canada). The apparatus consisted of a wooden box (50.5 x 73 x 122 cm) opened at the top and fitted with a trap door (38 x 60 cm) that can be opened using a rope and a pulley system. The apparatus contained a black plastic tube opening onto a green porcelain trough. A light was fixed above the apparatus. A tennis ball was fixed at the top of the apparatus and linked up to a fishing line. A tube linked up to an air compressor and another one linked up to a water gun (itself linked up to the air compressor) opened onto the trough. Auditory cues were played using a computer linked up to two speakers positioned on each side of the testing arena. The testing arena was cleaned at the end of daily experiments.


The Way Humans Behave Modulates the Emotional State of Piglets.

Brajon S, Laforest JP, Schmitt O, Devillers N - PLoS ONE (2015)

Overview of the testing arena and the apparatus.(A) Sketch of the testing arena viewed from the top, including the apparatus and the speakers; (B) Sketch of the apparatus viewed from the side, including the camera, the light, the plastic tube and the trough. In bold topography, a part of the material used for punishments, including the tennis ball relied on a fishing line, the air compressor relied on an air spray gun and a water spray gun; (C) Picture of the apparatus viewed from the front; (D) Picture of the apparatus viewed from the top with a piglet at the trough.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526664&req=5

pone.0133408.g001: Overview of the testing arena and the apparatus.(A) Sketch of the testing arena viewed from the top, including the apparatus and the speakers; (B) Sketch of the apparatus viewed from the side, including the camera, the light, the plastic tube and the trough. In bold topography, a part of the material used for punishments, including the tennis ball relied on a fishing line, the air compressor relied on an air spray gun and a water spray gun; (C) Picture of the apparatus viewed from the front; (D) Picture of the apparatus viewed from the top with a piglet at the trough.
Mentions: The testing arena was located in an experimental room separated from housing rooms and consisted of a 2.30 m2 arena made of plastic-coated expanded metal flooring with an apparatus on the narrow side (Fig 1). Two digital video cameras (Panasonic WV-CP 480, Panasonic, Mississauga, ON, Canada), one fixed above the apparatus, the other fixed above the testing arena, were used to record behaviour of piglets at 15 FPS and behaviour was analysed using a specialised recording and viewing software (Omnicast, Genetec Inc., Montréal, QC, Canada). The apparatus consisted of a wooden box (50.5 x 73 x 122 cm) opened at the top and fitted with a trap door (38 x 60 cm) that can be opened using a rope and a pulley system. The apparatus contained a black plastic tube opening onto a green porcelain trough. A light was fixed above the apparatus. A tennis ball was fixed at the top of the apparatus and linked up to a fishing line. A tube linked up to an air compressor and another one linked up to a water gun (itself linked up to the air compressor) opened onto the trough. Auditory cues were played using a computer linked up to two speakers positioned on each side of the testing arena. The testing arena was cleaned at the end of daily experiments.

Bottom Line: Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray).The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10).However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Agriculture and Agri-Food Canada, Dairy and Swine Research and Development Centre, 2000 College Street, Sherbrooke, Quebec, J1M 0C8, Canada; Université Laval, Department of Animal Science, 2325 Rue de l'Université, Quebec city, Quebec, G1V 0A6, Canada.

ABSTRACT
The emotional state can influence decision-making under ambiguity. Cognitive bias tests (CBT) proved to be a promising indicator of the affective valence of animals in a context of farm animal welfare. Although it is well-known that humans can influence the intensity of fear and reactions of animals, research on cognitive bias often focusses on housing and management conditions and neglects the role of humans on emotional states of animals. The present study aimed at investigating whether humans can modulate the emotional state of weaned piglets. Fifty-four piglets received a chronic experience with humans: gentle (GEN), rough (ROU) or minimal contact (MIN). Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray). Independently of the treatment (P = 0.82), 59% of piglets completed the training. Successfully trained piglets were then subjected to CBT, including ambiguous cues in presence or absence of a human observer. As hypothesized, GEN piglets showed a positive judgement bias, as shown by their higher percentage of go responses following an ambiguous cue compared to ROU (P = 0.03) and MIN (P = 0.02) piglets, whereas ROU and MIN piglets did not differ (P > 0.10). The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10). However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001). This study originally demonstrates that the nature of a chronic experience with humans can induce a judgement bias indicating that the emotional state of farm animals such as piglets can be affected by the way humans interact with them.

No MeSH data available.


Related in: MedlinePlus