A note on behaviour and heart rate in horses differing in facial hair whorl

Abstract

The relationship between facial hair whorl position and reactivity, as assessed by behavioural measures (handling score = HS; startle reaction to a suddenly appearing novel object = SR; latency to touch a novel object = LNO) and heart rate measures (mean HR; increase in heart rate = IHR) were studied using 55 Konik horses reared either under conventional stable conditions or in the forest reserve. Horses were classified into four groups according to the whorl position and/or shape: (1) high, single whorl above the top eye line, n = 9; (2) medium, single whorl between the top and the bottom eye line, n = 30; (3) low, single whorl below the bottom eye line, n = 10; and (4) elongated or double whorl, n = 6. Horses with a high whorl position demonstrated a lesser degree of manageability as expressed by a lower HS compared to individuals with medium (P = 0.002) or low whorl positions (P = 0.016). Horses with different whorl positions did not differ significantly in their startle response to a suddenly appearing novel object (P = 0.685). The horses with an elongated or double whorl, which appeared only in the forest group, took significantly longer to approach the novel object than horses with medium (P = 0.006) or low (P = 0.005) whorl positions. No significant differences in mean HR and IHR between groups (HR: P = 0.629 and IHR: P = 0.214) were found. In conclusion, this study supports the relationship between the position of the hair whorl on the horses’ head and their manageability during handling, as well as the latency to approach an unknown object.

Introduction

Anecdotally, a relationship exists between morphological traits or body conformation and temperament traits in domestic animals (Sumiński, 1930, Grandin et al., 1995, Tellington-Jones and Taylor, 1995). Recently, the position of hair whorl patterns on the forehead was suggested to be related to breeding soundness measures in cattle (Meola et al., 2004). As the displacement of the scalp line occurs in a number of syndromes (Wade and Sinclair, 2002), a common ectodermal embryonic origin has been suggested as the rationale for a possible interrelationship between nervous reactivity and hair patterns (Smith and Gong, 1974). Several reports concerning the relationship between whorl characteristics and specific behaviours in cattle have been published (Grandin et al., 1995, Randle, 1998, Lanier et al., 2001). To our knowledge, no similar studies have been conducted in horses, with the exception of a questionnaire comprising of 1500 different horses collected in 1965 by Tellington-Jones and Taylor (1995). Although a behaviour of great number of horses was characterised in the latter study, no statistical evidence was presented to support authors’ conclusions.

The aim of the present study was to determine more precisely if horses of the same breed and being handled in the same way, but having different facial hair whorl placement, would differ in their reactivity, as assessed by behavioural tests and heart rate. The results may have practical implications in the early prediction of horses’ reactivity and/or behavioural characteristics, which are important at handling, or while riding or driving horses.