Could Work Be a Source of Behavioural Disorders? A Study in Horses

Abstract

Stress at work, as shown by a number of human studies, may lead to a variety of negative and durable effects, such as impaired psychological functioning (anxiety, depression…). Horses share with humans this characteristic of working on a daily basis and are submitted then to work stressors related to physical constraints and/or more “psychological” conflicts, such as potential controversial orders from the riders or the requirement to suppress emotions. On another hand, horses may perform abnormal repetitive behaviour (“stereotypies”) in response to adverse life conditions. In the present study, we investigated whether the type of work the horses are used for may have an impact on their tendency to show stereotypic behaviour (and its type) outside work. Observations in their box of 76 horses all living in the same conditions, belonging to one breed and one sex, revealed that the prevalence and types of stereotypies performed strongly depended upon the type of work they were used for. The stereotypies observed involved mostly mouth movements and head tossing/nodding. Work constraints probably added to unfavourable living conditions, favouring the emergence of chronic abnormal behaviours. This is especially remarkable as the 23 hours spent in the box were influenced by the one hour work performed every day. To our knowledge, this is the first evidence of potential effects of work stressors on the emergence of abnormal behaviours in an animal species. It raises an important line of thought on the chronic impact of the work situation on the daily life of individuals.

Detecting and Measuring Back Disorders in Nonverbal Individuals: The Example of Domestic Horses

“…Being restrained in an unnatural posture during working time is also pointed out both as a potential source of emotional and behavioral disturbance (Hausberger et al, 2009von Borstel et al, 2009) and back disorders (Kobluk & Gross, 1996;Rhodin et al, 2005). Thus, both headshaking and unnatural postures at work might be considered as a warning of potential back disorders' presence or at least as risk factors of their development.…”

“…Teeth grinding, groaning, and "abnormal exploratory behaviors" were reported in horses with back pain (Driessen & Zaruco, 2007;McGreevy et al, 2010), however no details are available on the behavioral patterns included in the "abnormal exploration behaviors," preventing their identification by other observers. Hausberger et al (2009) investigated the impact of the discipline on the expression of stereotypic behaviors. Their observation of horses of the same facility, differing only in the discipline performed, highlighted that the type and occurrences of stereotypic behaviors differed according to the discipline: voltige horses (that turn in circles around a lunging person, carrying some gymnasts) appeared to be the least prone to stereotypic behaviors and performed relatively ''mild types'' such as tongue play, whereas dressage/high-school horses presented the highest incidence and most disabling types of stereotypic behaviors (cribbing/ windsucking: The horse grasps a fixed object with its incisors, pulls back, and draws air into its esophagus while emitting a characteristic pharyngeal grunt; head shaking: The horse bobs repetitively its head up and down or tosses its head in recurrent and sudden bouts; Mills, 2005).…”

“…Several authors also suggested that emotions are a possible source of back disorders (humans: Dionne et al, 2005;Houtman, Bongers, Smulders, & Kompier, 1994; horses: Ridgway & Harman, 1999). Riding per se may be both a source of emotion (Schmidt, Aurich, Möstl, Müller, & Aurich, 2010) and of physical constraints, leading to a double potential effect on the emergence of back disorders (Hausberger et al, 2009. The type of training may also affect back tension through emotional impacts.…”

Plasma cortisol and faecal cortisol metabolites concentrations in stereotypic and non-stereotypic horses: do stereotypic horses cope better with poor environmental conditions?

“…In addition to the “classical” repetitive behaviours, following previous studies performed in other species and in horses, repetitive licking/biting (walls, grids, feeding trough) were recorded as further abnormal repetitive behaviours ( e.g. [3,26]). Note that we use here the term “stereotypic behaviours” as a broad descriptive term encompassing all repetitive behaviours observed, as they all typically appear in captive sub-optimal conditions that induce motivational frustration and/or physical discomfort.…”

Animal Welfare: Could Adult Play be a False Friend?

“…The prevalence of stereotypies and other ARB in horses has been shown to relate to frustration related to restricted roughage availability, space and social restriction, in addition to early stresses (such as early weaning) or to working conditions (e.g., Hausberger, Gautier, Biquand, Lunel, & Jégo, 2009;McGreevy, Cripps, French, Green, & Nicol, 1995;Mills, 2005). Thus, we performed observations of the horse's behavior in their stall.…”