How Studying Interactions Between Animal Emotions, Cognition, and Personality Can Contribute to Improve Farm - Genetics and the Behavior of Domestic Animals - page 85

avoidance (immobility) ( Erhard and Mendl, 1999 ). Subtle expressions can
also be regarded as fear indicators; for example, expressive movements like
head postures and facial expressions, alarm calls, and the release of alarm
odors or pheromones. These fear-related responses play important social
roles by serving as alerting signals for conspecifics. Few studies that have
been recently carried out in ruminants provide some insight that ear postures
may be useful in assessing emotions in farm animals. In cattle, a high occur-
rence of pendulous ear postures was used as an indicator of the animals' pos-
itive rating of their favorite grooming sites ( Schmied et al.,2008 ). We found
that sheep point their ears backward when they face an unfamiliar or an
unpleasant event and they react to a sudden event by an asymmetric posture
of their ears ( Boissy et al., 2011 ). These first results offer a promising step
in the characterization of specific emotion-related facial expressions in farm
animals since measuring ear postures constitutes a reliable non-invasive
method for monitoring the emotional reactions in animals.
Fear-eliciting events can also affect the activity in which the animal is
engaged: low levels of fear can enhance activity (e.g., attention, investigation)
whereas intense fear can disturb or terminate an ongoing activity. Indeed,
fear inhibits all other behavior systems including feeding, exploration, sexual
and social interactions ( Jones and Boissy, 2010 ). Finally, conflict between a
negative emotional state and a positive motivation may generate a compulsive
behavior; for example, a disturbed or hungry pig bites a chain or bar. Activation
of the sympathetic nervous system, including the adrenal medulla, and the
hypothalamic adrenal system are major neuroendocrine responses

associated with negative emotions ( Morm`de et al., 2007; von Borrell et al.,
2007 ) but they also accompany positive rewards such as food delivery, sexual
interaction. Frightening stimulation also elicits a range of complex changes
in central nervous mechanisms, such as neural pathways and neurotransmitters
( Gray, 1987; Phillips et al., 2003; Rosen, 2004 ).

pituitary

Various Ways of Assessing Fear and Anxiety
Varied experimental situations have been designed to study fear in farm
animals and most of them were originally developed for laboratory species
(for a review, see Forkman et al., 2007 ). Since Hall's classic work (1936),
the open-field or novel arena test has been extensively used in rodents.
Generally, a single animal is placed in a large novel arena and the amount of
defecation and activity is interpreted as reflecting the emotional response
to novelty. Later work showed that this test also incorporates many other
threatening stimuli, such as absence of shelter and landmarks, human contact,
social isolation, and bright light. Many other paradigms devised to assess fear
in rodents, for example exposure to a predator or a novel object, confinement,
handling, inescapable noxious stimulation, and passive or active avoidance
conditioning ( Ramos et al.,1997 ) have also been used in farm animals from