Partners with Bad Temper: Reject or Cure? A Study of Chronic Pain and Aggression in Horses

Abstract

BackgroundExperiencing acute pain can affect the social behaviour of both humans and animals and can increase the risk that they exhibit aggressive or violent behaviour. However, studies have focused mainly on the impact of acute rather than chronic painful experiences. As recent results suggest that chronic pain or chronic discomfort could increase aggressiveness in humans and other mammals, we tested here the hypothesis that, in horses, aggression towards humans (a common source of accidents for professionals) could be linked to regularly reported vertebral problems of riding horses.Methodology/Principal FindingsVertebral examination and standardized behavioural tests were made independently on the same horses. Here we showed that most horses severely affected by vertebral problems were prone to react aggressively towards humans (33/43 horses, chi-square test, df = 1, χ2 = 12.30, p<0.001), which was not the case for unaffected or slightly affected horses (9/16 horses, chi-square test, df = 1, χ2 = 0.25, p>0.05). The more affected they were, the fewer positive reactions they exhibited (rs = −0.31, p = 0.02).Conclusions/SignificanceThis is to our knowledge the first experimental evidence of such a link between chronic discomfort/potential pain (inferred from the presence of vertebral problems) and aggression, suggesting that chronic painful experiences may act in ways similar to those of acute experiences. Chronic discomfort or pain may often be overlooked when facing “bad tempered” individuals, whether humans or animals. This experimental study confirms the importance of including chronic discomfort or pain as a major factor in interpersonal relations and models of aggression.

On the significance of adult play: what does social play tell us about adult horse welfare?

“…Manual palpation was performed from head to tail and data included the percentage of vertebrae affected. Double checking by a second practitioner led to highly correlated results and confirmed reliability of results in the absence of radiographic data, impossible in this field situation (Cauvin 1997;Fureix et al 2010;Lesimple et al 2010). …”

“…An evaluation of the horses' spine was performed by a 20 years experienced licensed chiropractor who was totally blind to the results of other observations and did not know the horses beforehand (all details in Fureix et al 2010;Lesimple et al 2010). Manual palpation was performed from head to tail and data included the percentage of vertebrae affected.…”

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

“…Chronic back pain is identified as a source of irritability and bad temper in humans (Dionne et al, 2005) as well as in horses (Cauvin, 1997;Landman et al, 2004). Fureix et al (2010) submitted 59 riding school horses to five behavioral tests in order to evaluate the human-horse relationship while their spine was examined independently at rest by an experienced practitioner. It appeared that more than 75% of the severely affected horses were aggressive towards the experimenter, while only 50% of the healthy ones were.…”

Animal Welfare: Could Adult Play be a False Friend?

“…Vertebral problems are often underestimated, while they are a major and highly common problem (Fonseca et al, 2006;Jeffcott, 1980;Lesimple, Fureix, Biquand, & Hausberger, 2013). Recent studies, as well as veterinarian reports, showed that horses with more vertebral problems, hence chronic discomfort, are more aggressive towards humans (Fureix, Menguy, & Hausberger, 2010). Aggressiveness reflects altered well-being in humans (Anderson & Bushman, 2002) as well as pigs (Day, de Weerd, & Edwards, 2008;Turner, Ewen, Rooke, & Edwards, 2000).…”