Equine Science & Technology

Equine Parasites

Equine ParasitesCommon Internal Parasites In North America, horses are affected by more than

80 internal parasites, which inhabit nearly every organ.

Parasites are so widespread that no horse escapes all of them.

Strongyles, ascarids, and bots are generally the most injurious of all internal parasites.

Equine ParasitesAscarids (Large Roundworms) Found in the small intestines of equines. Especially affect foals and young animals. Are damaging to the liver and lungs of the horses. Ascarid eggs pass to the outside with the feces. May cause ruptured intestines, lung damage,

impaired growth, rough hair coats, etc.

Equine ParasitesBotsHighly specialized parasites in their larval stage that

attack horses, mules, and zebras. There are three species of horse Bot flies: Nit fly,

Throat bot, and the Nose bot. Eggs are attached to the hairs of the host. Eggs usually hatch within two to seven days, and the

young larvae soon enter the horse’s mouth.

Equine ParasitesBots Larvae pass to the stomach and intestines. Even though the bot fly does not sting the animal,

horses may toss their heads in the air, strike the ground with their front feet, and rub their noses on any convenient object.

May cause digestive upset, colic, lowered vitality, and reduced work output.

Equine ParasitesPinworms (Rectal Worms) Pinworms are widely distributed in horses throughout

the United States. Horses become infected by swallowing the eggs with

feed or water. The worms mature in the large intestine, principally in

the dorsal colon. Evidence of the pinworms may be seen in the feces. Symptoms include irritation of the anus and tail

rubbing.

Equine ParasitesStomach Worms Stomach worms consist of a group of different kinds

of parasitic worms responsible for inflammation in the stomach or a condition known as stomach sores.

The mature worms in the stomach lay many eggs.

Equine ParasitesStomach Worms Horses become infected after swallowing infested

flies or the larva that escape from the flies. Can lead to intense itching and an inflammatory

reaction.

Equine ParasitesStrongyles (Large Strongyles, Small Strongyles) The most serious threat to the health and life of the

horse. Approximately 40 different species of Strongyle. Found throughout the U.S. wherever horses are

pastured. Heavy infestations may result in marked unthriftiness,

loss in capacity to perform work, and even death.

Equine ParasitesTapeworms Three different species that affect horses. Anoplocephala perfoliata is the most common and

the most damaging of the three. Found in the small intestine

or the cecum.

Equine ParasitesCommon External Parasites

Blow fly Principal breeding ground in dead and putrefying

flesh. Irritate and destroy the ability of the skin to function. Can be identified by three stripes on the back and a

metallic luster.

Equine ParasitesLice A small flattened, wingless insect parasite. Feeds on scales, hair, and skin exudates. Are always more abundant on weak, unthrifty

animals. More troublesome during winter.

Horse-biting Louse

Equine ParasitesMites Produce a specific contagious disease known as

mange (scabies, scab, or itch). Attack members of both the plant and animal

kingdom. Injury from mites is caused by irritation and blood

sucking, the formation of scabs, and other skin problems.

Equine ParasitesMites Heavy infestation results in a characteristic

hairless, scaly appearance.

Equine ParasitesTicks Classified into two groups: hard ticks and the

soft ticks. Most are three-host ticks (they utilize three

hosts during the life cycle). Massive infestations may cause anemia, loss

of weight, and even death.

Equine ParasitesInternal Parasite Prevention Separate the animal from its own excrement. Rotate wormers periodically. Keep pastures clean. Isolate and treat newly added horses before allowing

them to share pastures, pens, stalls with resident horses.

Equine ParasitesInternal Parasite Prevention Take periodic fecal examinations at random. Read and follow all label directions explicitly. If

there are any questions … call the veterinarian. Avoid ground feeding.

Equine ParasitesExternal Parasite Prevention Practice good nutrition and grooming. Avoid too heavy concentrations of horses. Select the right insecticide and apply to the animal in

accordance with the manufacturer’s directions. Keep stalls and paddocks clean.

Equine ParasitesGeneral Horse Health ManagementThe following health program is recommended for all

horses.

1. Feed each horse a nutritious and well-balanced ration.

2. Provide regular dental care and farrier service.

3. Know the signs of ill health and the signs of good health.

4. Have on hand first-aid supplies, and know when and how to use them in case of accident or sudden illness.

Equine ParasitesGeneral Horse Health Management

5. Vaccinate against the most common diseases.6. Avoid public feeding and watering facilities.7. When signs of infectious disease are encountered,

promptly isolate affected animals, provide them with separate water and feed containers,

and follow the instructions and prescribed

treatment of the veterinarians.

8. Prevent and control parasites.

Equine ParasitesBasic first-aid careWoundsAlthough wound treatment will vary according to form

and severity, the following steps may be involved.1. Stop the bleeding. If bleeding is severe pressure

may be applied by placing a pad on the wound and bandaging over it.

2. Clean the wound by washing it with cotton swabs soaked in warm saline salt solution. Remove all foreign material (objects and dirt) hair, and torn tissue.

Equine ParasitesWounds3. Clip or shave long hair. (It is often best not to

remove short hair, because of the damage of contamination) from around the wound to a distance of about ½ in.

4. Apply first-aid powder according to the directions on the label.

5. Suture incised and lacerated wounds if necessary, with the decision being left to, and the work done by a veterinarian. Proper wound drainage should always be established.

Equine ParasitesWounds6. Protect against tetanus by administering

(a) a tetanus antitoxin if the animal is not already on a toxoid program, or

(b) a toxoid booster if the horse has been immunized previously with the product. Also, the veterinarian may inject an antibiotic.

7. Switch from powder to salve. As soon as a scab has formed over the wound, switch from first-aid powder to first-aid salve. Continue to keep wound clean.

Equine ParasitesBruises and Swellings1. Stop the hemorrhage with cold applications

together with firm, even pressure.

2. Use cold water showers and cold water bandages until the swelling stops.

3. Apply heat or liniment after the swelling has stopped.

Equine ParasitesColic Walk the horse slowly and quietly by leading. Keep the animal from rolling. Call your veterinarian for further instructions.

Equine ParasitesFounder (Laminitis) Treatment should be considered an emergency. Pending the arrival of the veterinarian, the horse should

be provided with support to the feet in the form of sand or a well bedded stall. Anti-inflammatory agents such as phenylbutazone are often recommended.

Equine ParasitesCommon Disinfectants

A disinfectant is a bacterial or microbial agent that frees from infection (usually a chemical agent that destroys disease germs or other microorganisms or that inactivates viruses).

Equine ParasitesAlcohol Used primarily for skin disinfectant and for

emergency purposes on instruments. 70% alcohol- the content usually found in rubbing

alcohol. Too costly for general disinfection, ineffective

against bacterial spores.

Equine ParasitesChlorines Kills all kinds of bacteria, fungi, and viruses,

providing the concentration is sufficiently high. Are corrosive to metals and neutralized by organic

materials. Not effective against TB organisms and spores.

Equine ParasitesIodine Extensively used as skin disinfectant for minor cuts

and bruises. Generally used as tincture of iodine, either 2% or

7%. Never cover with a bandage. Clean skin before applying iodine.

Equine ParasitesSoap Soap’s power to kill germs is very limited. Greatest usefulness is in cleansing and dissolving

coatings from various surfaces, including the skin, prior to application of a good disinfectant.

Staphylococci and organisms that cause diarrheal disease are resistant.