Dr. Janice Sojka

email jes@vet.purdue.edu

Horses - Introduction

• Herbivore
• Herd animal- Organized social structure
• Monogastric, ferments cellulose in the cecum and large colons
• Single hoof
• Gestation -11 months
• Reach maturity at 2 years, life span of 30 years

Horse - Equus caballus

• Kingdom Animalia
• Phylum chordata
• Class Mammalia
• Order Perissodactyla
• Family Equidae
• Genus Equus
• Species Equus caballus

• Horses evolved in great plains of USA 58 million years ago
• Horses were the last of the present day farm animals to be domesticated - 3,000 B.C. in central Asia
• Egyptians spread the use of the horse to other ancient civilizations

• OLDEN DAYS
• War
• Transportation
• Food
• Draft Animal- agricultural uses
• Sport
• MODERN TIMES
• Recreational Use
• Sport
• Food

• Live in small bands: up to 15 mares with their offspring and 1 stallion
• Eat forage (grasses) most of the day
• Non-territorial- move to food supplies
• Dominant mare is leader of the group
• Foals born in late spring

• 205 bones in skeleton

• cannon bone = finger

• hoof = fingernail

• Dentistry -- horses have 40 teeth, with continuous eruption throughout the life of the horse
• Large lung capacity and lots of muscling- horses are natural athletes
• Small stomach and large colons- horses evolved to eat small amounts continuously and to digest cellulose in the colons
• Horses are seasonally anestrus- cycle in spring and summer, not in fall and winter

• Horses now used primarily for recreation.
• Horses are bred if they are good athletes or have desirable conformation
• Spend many hours per day in a stall, turn out for exercise
• Fed hay and grain, often 2 large meals a day with hours in between with nothing to eat
• Horses mixed with strange horses frequently

Reproduction

• Animals retained for breeding if they have been successful on the race track, in show rings, or as performance animals. Animal’s fertility is NOT a factor.
• Many breed registries use Jan 1 as the universal birthday, thus many want foals born in January and February
• NET RESULT- Poor reproductive efficiency

Feeding Practices

• Consuming two calorically dense meals rather than nibbling constantly throughout the day; may lead to several severe problems:
• Stable vices
• Founder
• Colic

Stable Vices

• Horses are happiest when then are chewing. If this drive is not met they can begin to develop bad habits. These are called stable vices. Examples would include:

• The laminae are the areas of the hoof which hold the hoof wall onto the bone.
• Eating high grain or rich diets predisposes a horse to "laminitis" or founder which is swelling of the laminae
• This results in severe pain in the hoof, lameness, and may result in permanent injury to the hoof

Laminitis - Signs

• Horse attempts to get weight off feet- "camped under" stance, lies down excessively
• Will not not walk, trot, or turn willingly
• Abnormal growth to the hoof- characteristic rings
• In severe cases hoof may fall off

Laminits- Results

• If bone in hoof becomes detached from the hoof wall - life long severe lameness and death may result.  As the bone (P-3) detaches, the tendons at the back cause it's ventral rotation, so that it is no longer aligned parallel to the hoof wall.  For a radiographic demonstration of this, check the University of Pennsylvania School of Veterinary Medicine website
• If bone not detached but severe injury occurs - hoof wall will be damaged and require corrective trimming and shoeing for the life of the horse.

Laminitis Prevention

• No sudden changes in diet
• Limit access to green pasture in spring
• Limit amount of concentrate in a meal
• Lock up feed; make sure they cannot get into concentrate if loose
• Maintain good overall health

Laminitis Treatment

• Painkillers
• Medicine to lower blood pressure
• Prevent absorption of toxins by giving oral mineral oil
• Trimming and corrective shoeing of hooves

• Colic is the term used by horsemen to describe abdominal pain -"stomach ache" in horses.
• Colic is a very common disease of horses
• Horses with many parasites or on high grain diets are predisposed to developing colic
• Colic can range from mild discomfort to deadly - killing in hours

Why is colic so deadly in horses?

• Horses can not vomit. If excess gas or fluid builds up in the stomach, the stomach will rupture. This will lead to the death of the horse.
• All the large intestines are attached to the body via one main stalk. Thus they can act as pendulums and swing around in the body leading to twisted intestine.

Types of Colic

• Gas Colic
• Spasmodic Colic
• Impaction
• Thromboembolic
• Strangulation obstruction
• "False" colic

Colic - Prevention

• Teeth care
• Good quality feed, diet balanced between fiber and grain
• Make feed changes slowly
• Parasite control
• Access to potable water

Colic- Treatment

• Treatment of colic depends on the cause. In most instances a dose of pain killer is all that is necessary. In some instances major abdominal surgery is required.
• A veterinarian should be called if a horse shows either severe colic or low grade colic for more than several hours.

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