Comparison of head–neck positions and conflict behaviour in ridden elite dressage horses between warm-up and competition

Abstract

The use of specific head–neck positions (HNPs) in horse riding have been identified to directly affect wellbeing of horses. In the rulebook of the International Equestrian federation (FEI), HNPs with the nasal plane in front of the vertical are mandatory, as well as ensuring horses to be “happy athletes”. Deviations from this should be reflected in the scoring of dressage competitions. We investigated ridden elite dressage horses in warm-up areas and during competition, and hypothesised a relationship between the HNP, behavioural indicators and the scores. Forty-nine starters (83%) of an international dressage competition (Grand Prix Special (CDIO5*) at CHIO (Aachen (Germany) in 2018 and 2019) were examined. We analysed HNPs (angle at vertical, poll angle and shoulder angle) as well as conflict behaviour (CB), e.g. unusual oral behaviour (OB) and tail swishing (TS), in the warm-up area and during competition in 3 min-videos (6571 frames). Conflict behaviour was evaluated using the Observer XT with the focus animal method according to an ethogram. Scores given by judges in the competition were noted. Data were analysed with six linear mixed effects models, where phase of competition and year (both factors with two levels) were fixed effects, and the horse was a random effect. Dependent variables were poll angle, angle at vertical, shoulder angle, TS, OB and total CB. Further, we evaluated another three models to evaluate if the vertical angle affected the response variables (TS, OB or CB). Hereby, angle at the vertical (continuous) and year (factor with two levels) were fixed effects, and the horse was considered as a random effect. The horses’ nasal plane was behind the vertical more often during warm-up than during competition (−11° vs. −5°; P<.01). Further, the poll angle was larger during competition than during warm-up (28° vs. 24°; P<.01). Horses showed more total CB and OB during warm-up than during competition (count: 163 and 107 vs. 120 and 78; P<.01). Horses tended to show more CB and OB when their nasal plane was behind the vertical. Tail swishing was not affected by angle at the vertical. Scores given by the judges correlated with HNPs during competition (R = 0.38; P<.05). These results undermine animal welfare concerns during world class dressage competitions.