Equine Behavior

A Guide for Veterinarians and Equine Scientists

Paul McGreevy

• Editorial: Saunders Ltd.
• Año: 2012
• ISBN:
  9780702052927
• Edición: 2
• Categoría: Médecine
• Categoría: Sciences vétérinaires équines

Equine Behavior: A guide for Veterinarians and Equine Scientists is the quintessential reference for all who really want to know what makes horses tick.Research in horse behavior has made great strides in recent years. This book examines the truth behind modern trends and ancient traditions. Full of insight, it rounds up the latest findings of practitioners and researchers from all over the world, drawing on both cutting-edge research and best practice. With more than 1, 000 references, the book explores equine behavior from first principles, by considering the behavior of free-ranging horses and focusing on ways in which management and training influence the responses of their domestic counterparts. Equine physicians, trainers, handlers and owners all need to be students of equine behavior, because the first sign of a problem is often a change in behavior. So, whether you own, ride, lead, groom, feed or heal horses, what you observe is vital to your understanding.Behavioral problems in the stable and under saddle are a grave concern for equine veterinarians worldwide, because they can lead to poor performance, welfare issues, abuse and, ultimately, wastage. Traditionally, veterinarians gave priority to the physical health of their equine patients. This book is a unique attempt to demonstrate the way science can throw light on how and why problems and unwelcome behaviors arise. It also offers ways to bring about change for the better.Beautifully illustrated with more than 500 photographs and line diagrams, Equine Behavior: A guide for veterinarians and equine scientists is an essential resource for practising veterinarians, students and enthusiasts with a specific interest in horses, ponies, and donkeys. Professional trainers and handlers, equine scientists and behavior therapists will also find its contents invaluable.Paul McGreevy is Senior Lecturer in Animal Behavior at the University of Sydney's Faculty of Veterinary Science

• Features a practical, hands-on approach to all aspects of equine behavior
• Discusses all factors that effect equine behavior
• Contrasts normal behavior with abnormal behavior
• Reviews all behavioral problems
• Lists and reviews the latest drug therapies
• Addresses difficult-to-treat clinical problems such as head-shaking, with insights from the leading researcher in this area
• Provides a brief clinical evaluation of 'horse-whispering'
• Illustrates the key behavioral differences between horses and donkeys

Chapter 1 Introduction

Chapter contents

Evolution and classification

Evolutionary background

Classification of equids

Changing roles

Domestication

Current status

The horse’s future

Stable management

Traditional stable management

Modern stable management

Management practices

Behavior

Normal behavior in stabled horses

Abnormal behavior in stabled horses

Stereotypic behaviors

Introduction to evaluating behavior problems

References

Evolution and classification

Because the evolution of the horse has been dealt with many times elsewhere, I shall spare the reader detailed descriptions of three-toed forest-dwelling dog-like creatures. Suffice it to say that we have been left with a most remarkable animal that can exploit impoverished grazing niches by foraging on very poor fibrous material and digesting it quicker than ruminants. Various anatomical, physiological and behavioral features of the modern horse mean that it is useful to humans in many ways (Fig. 1.1).

Figure 1.1 Humans and horses have had a long association. From depictions in cave paintings such as in Lascaux, France (A), we know that horses were originally hunted as a source of food, but since then the relationship has been developed through teamwork (B) and companionship (C).

((C) Courtesy of Francis Burton.)

Evolutionary background

A plains feeder that does not disperse and defend territories individually or in pairs as foragers of richer resources tend to, the horse has a long nose that allows it to graze while maintaining surveillance above the sward. As an animal without horns or antlers it relies largely on caution, speed and agility as its chief means of self-preservation. A social herbivore that capitalizes on companions for added safety, mutual comfort and probably enhanced food detection, this is a creature that is likely to feel insecure when isolated. The social skills of horses account for some of the species’ pre-adaptation to the domestic context.

To digest material ruminants generally ignore, the horse needs a large fermentation chamber, the cecum. Obliged to carry this voluminous digestive vat, the successful horse must therefore have tremendous muscular power to shift its necessary and considerable bulk from rest to top speed in the event of danger, so it has developed the ability to use minimal physical effort to rest while standing. With its small stomach this ‘trickle feeder’ is obliged to forage frequently and has not evolved to eat and then ruminate in one spot. Instead it eats and moves and eats and moves. Restricting movement and imposing periods of fasting are therefore likely to be more profound insults to equids than to members of many other species.

Classification of equids

Prior to the beginning of domestication, in the late Pleistocene, long-term geographic isolation of equid populations occurred.¹ This led to the distinct species that exist today (Table 1.1). True horses (Equus caballus) occupied the Eurasian lowlands north of the great mountain ranges, while the asses occupied the arid zones of Asia. Crosses with asses, zebras and onagers are possible but the hybrids are normally sterile.

Order: perissodactyla (odd-toed ungulates)

Suborder: hippomorpha

Super-family: equoidea

Family: equidae.

Despite their sometimes great morphological differences, all the breeds, groups and types of domestic horses belong to one species, E. caballus. Populations such as ‘mustangs’ and ‘brumbies’ found roaming in North America and Australia are feral representatives of this species. Within the E. caballus the occurrence of isolated environmental niches has given rise to the types we see among modern horses. Equine remains found in the Siberian permafrost suggest the presence of two distinct types of E. caballus: a small, heavily set type and a finer-boned ‘Oriental’ type of up to 14.3 hands (150 cm). The latter, less sturdy version was probably swifter and most likely the forebear of our modern ‘hot-blooded’ animals (so named because of their adapted suitability to hotter climes), the Arabians and Thoroughbreds. Reactivity and athleticism are the core characteristics of the hot-bloods that have led to their being favored as race, performance and sports horses. To respond rapidly to pivotal stimuli such as the opening of the starting stalls and the impact of the whip, racehorses have been selected for heightened reactivity to environmental changes. It seems likely that this is why they are over-represented in surveys of abnormal behaviors in stables, behaviors that are seen by many as responses to aversive stimuli. The least reactive equids are the so-called ‘cold-bloods’, the heavy horses and solid ponies. In between the two groups are the ‘warmbloods’. These can be described as crosses between hot and cold bloods and are exemplified by European performance horse breeds such as the Hannoverian. The domestication process is ongoing. It is important to recognize that selection for reactivity and speed in modern racehorses and extraordinary gaits in dressage horses may run counter to durability and rideability, respectively.

Equus caballus and Equus przewalskii

Mitochondrial deoxyribonucleic acid (mtDNA) studies suggest that a divergence occurred as long ago as a million years,^2,3 between the modern horse (E. caballus) and its more numerous and diverse predecessors. The link between them was thought to be the pony-shaped Mongolian Wild Horse, Przewalski’s Horse (E. przewalskii). Apart from Caspian ponies that appear to be polymorphic in the diploid number (some having 64 chromosomes while others have 66),⁴ E. caballus has 64 chromosomes. Equus przewalskii, on the other hand, has 66 chromosomes in the diploid state. However, the recent publication of the horse genome⁵ has shown that E. caballus is not only related to E. przewalskii, they are essentially the same species.

Table 1.1 Classification of equidae

Common name	Species	Diploid chromosome number
Przewalski’s horse ([Mongolian] wild horse)	Equus przewalskii	66
Horse (domestic)	Equus caballus	64
African wild ass (and domestic donkey)	Equus asinus	62
Nubian wild ass	Equus asinus africanus
Somali wild Ass	Equus asinus somalicus
Asian ass	Equus hemionus	56
Mongolian wild ass	Equus hemionus hemionus
Onager	Equus hemionus onager
Indian wild ass	Equus hemionus khur
Kiang	Equus hemionus kiang
Grevy’s zebra	Equus grevyi	46
Common zebra	Equus burchelli	44
Chapman’s zebra	Equus burchelli antiquorum
Grant’s zebra	Equus burchelli boehmi
Selous’s zebra	Equus burchelli selousi
Mountain z...