Lesson 7

Digestive System and Colic

Digestive System

CHOKE

Obstruction of the esophagus. (This is an emergency situation.)

Clinical signs – Coughing, gagging, discharge from nose and mouth. The horse has difficulty breathing.

What to do: Call a veterinarian. Keep the horse walking and allow the horse to lower his head.

Do not use high pressure water hose. Carefully clean out horse’s mouth if possible. Massage the left side of neck over the obstruction (lump). Try to keep the horse calm.

What the veterinarian will do: Tranquilize the horse. Pass a stomach tube in an effort to gently dislodge the obstruction. The veterinarian may give medication to help the esophagus muscles to function more efficiently and give the horse time to get the obstruction through. Antibiotics and anti-inflammatory agents are usually indicated.

STOMACH ULCERS

Foals as well as adults can be prone to developing stomach and intestinal ulcers. Stress plays a major role in the cause. Performance horses are at greater risk due to stress of training and performance, and high grain diets. NSAID’s (Bute or banamine) can also be a cause.

Clinical signs – recurring colic, poor appetite, weight loss.

Diagnosis – Many veterinarians have long gastro scopes that can actually be passed down to the stomach and identify these ulcers.

Treatment and control – It has been shown that horses kept in stalls have fewer problems with ulcers when they are offered free choice hay. Grazing prevents the formation of ulcers. New studies show Alfalfa hay in the diet actually helps prevent the development of ulcers.

Treatment can include Gastrogaurd or Tagamet (to inhibit acid production in the stomach), Maalox or Mylanta to help protect the lining of the stomach.

COLIC

1. Colic

2. Non-strangulating Colic – Colic that won’t require surgical intervention to cure.

a. Spasmodic colic – spasms of the intestines causing mild abdominal pain.

b. Simple gas colic – Gas distention of the intestines causing abdominal pain.

c. Impaction colic – feed which impacts and causes a temporary lack of movement along the digestive tract, also causing abdominal pain. This includes sand accumulation from feeding in areas where soil is sandy.

Any of the above normally initiates as mild colic signs, but depending on the amount of gas buildup or the severity of the spasms, can show up as significantly painful to horses. Any colic in the horse should be considered an emergency, because it is much easier to prevent colic from becoming more severe by treating it appropriately as soon as possible.

Prevention:

1. Feed at same time everyday.

2. Examine your feeds closely and never feed spoiled feed or moldy, musty hay.

3. Keep feed amounts and quality consistent. Increase feed amounts gradually, and change feed types gradually.

4. Offer horses clean fresh water continuously.

5. Good horse management practices.

6. Regular psyllium in the diet (1 –2 cups per 1,000 lbs daily for 1 week a month) will prevent sand accumulation in the intestinal tract and prevent sand colic.

What to do before the vet comes:

Keeping the horse up and moving is helpful in easing the pain and preventing the horse from rolling. If the horse is lying down and is still, forced walking is not a necessity. Follow the instructions of your vet.

What the vet will do:

An initial exam to try and determine the nature of the colic. Usually pain relievers, antispasmotics, and possibly mild sedatives may be used to control the pain. The vet will most likely pass a stomach tube in an attempt to relieve any gas accumulated in the stomach, or possibly even siphon accumulated fluids off the stomach. If an impaction is suspected, mineral oil or other lubricants may be administered into the stomach via the stomach tube. Rectal palpation may be performed to aid in diagnosis.

Strangulating vs. non-strangulating colic. When the intestines are twisted or displaced surgical correction will usually be the only way to save the horse. It is usually not possible for the vet to determine, during the early stages of the colic, whether the horse will require surgery or not in order to cure the colic. The vet will monitor the horse closely using various diagnostic aids to determine whether surgery will be necessary. The costs of colic surgery can run upwards from $5,000, including pre and post surgical care. If surgery is contemplated it is wise to understand your horse’s chances of survival. The veterinarian should be able to give you an educated guess as to the chances of the horse surviving the surgery.

Other Specific Types of Colic

Blister Beetles

Blister beetles are found in alfalfa hay occasionally. They are very toxic to the horse and cause a deadly colic when ingested. These blister beetles are trapped in the hay during the bailing process.

Enteroliths

Hard concretions that can form in the intestine and cause blockage of the intestinal tract.

Enteroliths have been linked to pastures or water that is high in calcium or phosphorous (high

alkaline sources of water or feed). These stones can also occur from the horse ingesting a piece of string or nylon as may be found in halters, lead ropes, hay bags, and even old tires used as feed tubs.

Prevention in high alkaline areas of the country consists of adding vinegar (acidic) to the diet (4 oz per day).

DIARRHEA

Although horses will develop a loose stool on certain occasions, when a horse has a persistent or a foul smelling watery diarrhea, you should consider it a definite emergency.

Colitis - Inflammation of the colon (large intestine) which can be caused by bacteria (like salmonella), Potomac Horse Fever or other causes.

Vital signs should be taken and communicated to the vet during the initial call.

The vet will examine the patient, probably take blood and other laboratory samples, and may initiate treatment with re-hydrating fluids as well as other therapies.

Keeping the horse hydrated is one of the most critical parts of the treatment in cases of colitis, because the horse can dehydrate so rapidly when they develop diarrhea.

Prevention:

In areas where Potomac horse fever is a factor, vaccination is wise. Regarding other forms of infectious diarrhea, the horseman must keep in mind that over work or other forms of physical stress (physically overstressing the horse’s system) can lower the horse’s natural immunity and can lead to changes in the colon which could lead to colitis. Over use of certain antibiotics or anti-inflammatories (bute or banamine) can lead to acute colitis.

Internal and External Parasitic Diseases

and

Their Prevention and Treatment

Equine Internal Parasites

Parasite	Site of Infection	Life Cycle	Symptoms	Treatment	Control
Habronema (Stomach worm)	Stomach	Typical, but fly involved	Typical & wound contamination	Ivermectins, Quest, Strongid, or benzimidazoles	Good Mgmt., Fly control
Ascarids (large roundworms)	Small Intestine	Typical & larvae migrate through lung & liver	Typical & Young horses – cough, snotty nose, impaction	Same as above	Good Mgmt.
Small Strongyles	Large Intestine	Typical & cysts in mucosa	Typical & Colics in spring when cysts mature	Same as above *Quest and Ivermectins effetive against cysts	Good Mgmt.
Large Strongyles (Bloodworms)	Large intestine	Typical & larve migrate through intestinal blood vessels	Typical & anemia and thromboembolic colic	Same as above *Quest and Ivermectins effective against migrating larvae	Good Mgmt.
Threadworms	Large intestine	Typical & mares milk to foal	Foal diarrhea (7 days to 3 weeks of age)`	Ivermectins, quest, strongid, benzimadazols	Good Mgmt& Prevention- Ivermectins or quest to mare day of foaling
Pinworms	Large Intestine	Typical & eggs sticky found on rectum and anus	Typical & tail itching and rubbing	Ivermectins, quest, strongid, benzimidazoles (can give when see tail rubbing)	Good Mgmt.
Bots	Stomach	Part of life cycle of Bot Fly (larval stage in stomach)	Typical & see bots in manure, Seasonal – Bot eggs (nits) on chest and upper leg hair	Ivermectins, Quest	Fly control. Razor to nits. Warm water to nits
Tapeworm	Sml. Int.	Typ.&mite	Colic	Strongid X 2`	Good Mgmt

Bots

Typical Life Cycle – Adults in intestines pass eggs into manure, eggs hatch and become infective larvae, ingested by horse and become egg laying adults in intestines.

Typical Symptoms of severe infestation- poor hair coat, pot belly, poor doer, unthrifty, poor appetite, no energy, anemia, pale mucous membranes.

Good management practices

1. Well fed horses have fewer parasite problems.

2. Clean up manure: A. from stalls daily B. from paddocks every other day C. from pastures regularly (if possible).

3. Pasture rotation.

4. Good worming program ( worm all horses on premises at same time).

5. Strongid C daily.

6. Don’t feed off the ground.

7. Manure management:

A. compost pile - heat kills worm eggs)

B. Haul off manure

C. manure spreader – exposes eggs to sun (hot and dry) which kills eggs during certain season

D. horses won’t graze where they have droppings.

DEWORMING PROGRAM

Readily Available Dewormers:

Ivermectins: Eqvalen, Zimecterin, & Quest - These will get all worms and bots.

Benzimidazols: Anthelcide, Panacur - These will get everything, but the bots

Pyrantel: Strongid, Strongid C – These products will get everything, but bots. They are also available as a daily feed additive for constant control of parasites (except bots).

Praziquantel: This is a recently available compound that controls tapeworms. It is found as an addition to Ivermectin wormers (Zimecterin Gold), Quest (Quest Plus) and other combinations, as well as by itself in some products.

Deworming Schedules

Foals – Every 2 months until 1 year of age then deworm as an adult horse.

Adult Horse – Every 3 months - fall (after first frost) and spring. Deworm for bots and all roundworms. (Quest or ivermectins)

Summer and winter – deworm for all roundworms. (Strongid, pyrantel, benzimidozoles)

Daily worming - Very effective – about 70 cents a day per horse. Strongid C - Still must worm for bots fall and spring.

Care must be taken when worming a heavily infected young horse. Large roundworms may cause impaction colic.

Other control measures

1. Feed in troughs or pails (not off the ground).

2. Clean stalls and paddocks at least every other day.

3. Compost piles will kill larvae.

4. Stalled horses and dry lot horses have fewer problems with parasites.

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