Equine Behavioral Medicine

Bonnie V. Beaver

• Publisher: Academic Press
• Year: 2019
• Print ISBN: 9780128121061
• eBook ISBN: 9780128122457
• Topic: Ciencias biológicas
• Subtopic: Medicina veterinaria

Equine Behavioral Medicine provides an essential resource for those who work with, study, and provide care to horses. It provides critical knowledge to help users understand the complex aspects of their behavior in order to benefit the animal, observe safe practices, and advance research in this area. The book includes current information on normal horse behavior and problem behaviors, particularly those associated with medical conditions, changes in the nervous system, and the use of drug therapy. Readers will gain a comprehensive understanding of the differences of the sensory systems and the concepts of learning that are helpful for successful treatments and safety.With the use of psychopharmacology becoming increasingly common by veterinarians, including for abnormal behaviors, is important to understand the rationale for the use of these medications. Understanding the intimate relationship between behavior, physiology, and health is key to practitioners, students, professionals, and others who work with, or care for, horses.- Pulls together the current published science on equine behavior into chapters covering a variety of specific behavioral topics- Features discussion based on an extensive review of the literature- Includes a thorough reference list in each chapter for those who might be interested in further research

Chapter 1

The History of Horses and Their Relationship to Humans

Abstract

The history of how the horse came to be is one of the best researched histories of all animals and includes DNA evidence going back even further than for humans. Modern horses, both tamed and free-roaming, are common sights around the world. While horses were the last of our livestock species to be domesticated, their longtime association with humans has changed the ancient world in more ways than any other animal. Even today, the human-horse relationship is evolving, as are the techniques we use to work with the horse. They are pets and pests; draft animals and beasts of burden. The more we understand about them, the better is the bond between us.

Keywords

Equine evolution; Equine genetics; Human-animal bond; Ancestor; Domestication

Horses Throughout History

Throughout human history, humans have been fascinated by the horse, and this creature and its ancestors have held a fascination for scientists as well. The evolution of the horse is the best known of all animal species because of a rich archive of prehistoric fossil bones. How the equine species came to be is still somewhat up for debate because of the many subspecies that developed over time, but there is no debate about the major contributions this animal has made to the development of the world.

Evolution

The boney records of horse relatives are rich, and they show the skeletal and tooth adaptations that led to the modern horse. Because changes occurred slowly, scientists have a fairly good picture of how the modern horse came to be, at least until about 25 million years ago (mya). Then, the family tree started to change rapidly, developing many branches. This branching led to a variety of theories as to the exact lineages. While modern DNA analysis of ancient bones would be desirable, it is nearly impossible because of bone mineralization and soft tissue degradation or replacement. The oldest sample analyzed to date is approximately 750,000 years old, from a foot bone preserved in the Canadian permafrost.^1–3 While this date is 9–10 times older than analyses of archaic humans, it is nowhere near the age of the oldest horse relative or most of the branching. Comparisons, then, rely on physical features, and for ancient horses, those features are primarily in the skull, feet, and teeth. Modifications in these structures accompany adaptation to the environmental changes.^4–6 Tropical forests became dry plains, and tender plants growing on soft ground gave way to coarse grasses on hard earth. Feet changed from four or five digits to one. Legs grew longer to travel farther for food, and necks got longer as the animal got taller to allow it to reach grass as it changed from browser to grazer. Successive ancestors also became larger in body mass.^7,8 The general description of body size suggests there was a relatively constant increase over time, although that description is a little oversimplified. The earliest ancestors gradually increased in weight, topping out around 110 lb (50 kg). This remained fairly constant from 57 mya until approximately 25 mya. After that, the increase tended to be steeper.⁷ The cheek teeth of horse ancestors also changed over time. They became more adept for grinding the harsher grasses instead of chewing tender browse by developing flatter, grinding surfaces and taller crowns.^6,9,10 Internal casts from ancient horse skulls show that size and complexity of the brain also continued to develop.^6,11 Although physical proof is lacking, it is reasonable to assume that soft tissue structures would also change, particularly the gastrointestinal tract.⁵

For the most part, the ancestors of the horse evolved on the North American continent. Occasional branches crossed the Bering Strait land bridge when it was exposed, and some moved into South America after the Isthmus of Panama joined the two continents between 12 and 15 mya. It was not until several thousand years ago that the horse completely left North America.

Eocene (56–33.9 mya)

Eohippus (also known as Hyracotherium) is considered the “grandfather” in the horse’s lineage, dating back to about 55 mya (Figure 1-1).^14,21 This was a tiny mammal typically described as the size of a large house cat but estimated to weigh about 50 lb (25 kg).^6,7 The head and neck were relatively short, but the legs were slightly longer than would be expected. The feet of the Eohippus had five toes on each forelimb, with digits 2–4 having small protohooves instead of claws, and the first digit, corresponding to the human thumb, was off the ground. On the hind limbs the second, third, and fourth digits had small hooves. The first and fifth digits were vestigial and did not touch the ground. Like ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• About the Author
• Acknowledgments
• Chapter 1: The History of Horses and Their Relationship to Humans
• Chapter 2: Equine Behavior of Sensory and Neural Origin
• Chapter 3: Learning
• Chapter 4: Equine Communicative Behavior
• Chapter 5: Equine Social Behavior
• Chapter 6: Equine Reproductive Behavior
• Chapter 7: Equine Maintenance Behaviors
• Chapter 8: Equine Locomotive Behavior
• Chapter 9: Equine Behavioral Medicine
• Chapter 10: Equine Behavior Problems
• Chapter 11: Equine Welfare
• Index