Tuesday, August 30, 2011

COLIC QUIZ: Test YOUR knowledge about this common killer

            Colic, a term used for any kind of abdominal pain originating in the horse’s gastro-intestinal tract, is one of the most common and most feared of any equine emergency. The high incidence of colic can be attributed to a number of factors including feeding strategies, environmental variables, and the physiology of the horse’s digestive system.  The fear factor is due to colic’s well-deserved reputation as a killer of horses, and because many horse owners feel helpless when faced with the prospect of a colicking horse. However, despite its fearsome reputation, colic is usually not fatal, and most cases resolve without surgical intervention. A major study conducted by the USDA’s National Animal Health Monitoring System found that the incidence of colic was 4.2 events/100 horses per year, with a fatality rate of 11 percent. That means that less than one out of every 200 horses will die in any given year from colic.
Still, horse owners who have experience with this ailment know that each case is like an earthquake: when it starts, you simply have no way of knowing if it is “the big one”. Therefore, it is essential to understand the signs of colic – and what steps to take (and not take) until the vet arrives.  It is also imperative to be familiar with the causes of colic, as some colics are preventable if the proper measures are taken.
Here is a quiz to help you test your knowledge of colic. Don’t worry, we’ve given you the answers, too – some of which may surprise you!

1. True or false:  Curling the upper lip (flehmen) can be a sign of colic.

True. Most of us are familiar with the “classic” signs of colic – repeated or violent rolling, pawing, biting or kicking at the flank, and lack of bowel movements. However, colic can present with a whole host of symptoms, some of which often go unrecognized. These include:

-  Decrease or total lack of appetite
-  Listlessness or depression
-  Kicking, biting or looking at belly or flank
-  Pawing
-  Swishing tail
-  Sweating
-  Rolling, especially violent rolling.
-  Lying down with reluctance to get up, or repeatedly lying down and getting up.
-  Groaning/Bruxism (grinding teeth)
-  Lack of bowel movements
-  Standing stretched out as if trying to urinate but not doing so
-  Resting heart rate of more than 44 beats per minute
-  Respirations greater than 30 breaths per minute
-  Flared nostrils
-  Lack of or reduced digestive sounds
-  Excessive digestive sounds
-  Pale, blue, or very red gums
-  Abdominal distension (bloating)
-  Curling the upper lip (flehmen)
-  Increased or uncontrollable activity

2. True or false:  I can reliably test my horse for sand accumulation in the gut by performing a fecal sand sedimentation test.

False.  Sand accumulation is a major cause of colic in horses. Horses ingest sand from grazing, especially on overgrazed pastures, and also from being fed off the ground. Many veterinarians and diligent horse owners regularly perform fecal sand sedimentation tests to try to see if the horse has a large amount of sand in the gut. To perform this test, you take five or six fresh manure balls (ones that haven’t touched the ground), dissolve them in water (some use a large mason jar, while others prefer a bucket or large plastic bag), shake the slurry up, wait several minutes, then carefully pour out the floating and cloudy stuff. After repeating this process several times, you should be able to see any sand that has sunk to the bottom of your container. More than a teaspoon is generally thought to indicate a problem. However, as Charles Ley, Dipl ACVIM, PhD, of Uppsala University in Sweden explains, “Sand excretion in healthy horses has been studied by fecal sand sedimentation testing, but the method is flawed for two reasons: it does not provide a quantification of the intestinal sand content, and it has a low sensitivity as a test for intestinal sand accumulation with a large number of false negatives. Due to these factors, it should not be used as a gold standard for diagnosing sand impactions or other sand-related problems.” Therefore, not finding sand doesn’t mean your horse is free from sand accumulation, but if you test repeatedly and do find sand consistently, this would indicate a problem.

3. True or false: Switching from one type of hay to another can cause colic.

True:  Rapid changes in feed are a common cause of colic in domestic horses. This is due in part to the fact that a significant portion of the equine digestive process is accomplished with the help of microbes that live in the GI tract, and different types of hay, grass and grain require a different balance of microbes in order to be broken down effectively. It takes time for the horse’s gut to cultivate a new “garden” of microbes, so most veterinarians recommend introducing any kind of new hay, grain or grass gradually over a period of two weeks.  Rapid increases or decreases in the amount of feed can also lead to colic, as well as other problems. Increasing concentrates quickly is a proven risk factor for colic (as well as laminitis), while cutting a horse’s diet down suddenly can lead to ulcers, which are another common cause of colic.  Any increase or decrease should therefore also be made gradually.

4. True or false:  Poor dentition (tooth problems) can lead to weight loss, but does not increase the risk of colic.

            False. Hay and grass are full of tough fiber called cellulose. In order to digest cellulose adequately, horses must first grind the fiber into smaller size fragments with their teeth.  Horses with inadequate dentition are unable to properly masticate (chew) the hay – and this can lead to colic.  States Elizabeth Carr, DVM, PhD, Dipl. ACVIM, ACVECC, assistant professor in Michigan State University's Department of Large Animal Clinical Sciences, “Poorly ground fiber can end up forming a firm mass as the water content is removed in the gut, and it can result in an impaction of the distal intestine (large and small colon)”.  Problems that can prevent a horse from chewing properly include the formation of points, ramps or waves on the teeth, all of which can develop as a result of day to day chewing. Older horses may also have problems with their teeth simply wearing down, as the teeth stop erupting when a horse is in its 20s. Having a veterinarian check your horse’s teeth at least once a year is the best way to avoid dentition-related colic.

5. True or false:  Dehydration can lead to impaction colic, so this type of colic is more likely to occur in the summer, when horses are sweating profusely.

False. Although impaction colic can be seen at any time of year, it occurs more frequently during cold weather. This is often due to lower water consumption, which happens because horses are less thirsty in cold weather and may be reluctant to drink very cold water. Water is critical for normal intestinal function, and any level of dehydration can make it more difficult for the horse to move ingesta through its intestines. Basically, the drier and coarser the feed, the more likely it is to form a blockage.

6.  Colic surgery these days has a very high success rate.

            True. While it used to be true that 50% or more of horses undergoing colic surgery would not survive more than a short time, the reality of colic surgery today is much more positive. Reports L. Chris Sanchez, DVM, PhD, Dipl. ACVIM, Associate Professor at the Island Whirl Equine Colic Research Laboratory at the University of Florida, “Colic surgery typically offers a very good prognosis for survival.  Overall, approximately 85% undergoing surgery for colic survive to discharge from the hospital.  
Many factors contribute to this success, including improvements in anesthesia, surgical technique, and aftercare. Also, transporting horses with surgical lesions to referral centers early clearly plays an important role as well. Of course, Some problems, such as a simple displacement of the large colon, offer a better prognosis than others.”

7.  A colicking horse should be kept walking.

            False. This myth remains widespread today, despite research that has shown that in most cases, the practice is of no benefit and may actually be detrimental. As Dr. Sanchez emphatically states, “It is very important to get the word out that it is absolutely not necessary to force a horse to keep walking. Doing so for long periods of time can actually tire the horse and increase dehydration.  If a horse will lie quietly, it is fine to let it do so.” The only time it is advisable to get a horse up and walking is if the horse is rolling violently or thrashing in such a way that it may harm itself or others, In these cases, walking may help distract the horse from its suffering.

8.  Diets high in concentrates increase a horse’s risk of colic.

            True.  Diets high in concentrates contribute to the extremely high incidence of gastric ulcers seen in domestic horses – and ulcers can lead to colic.  Concentrates are rich in fermentable carbohydrates, which produce volatile fatty acids as they break down, and these can cause cell damage, inflammation, and ulceration in the tender part of the stomach known as the squamous mucosa.  Concentrates also require much less “chew time” than hay, which means the horse produces less saliva to eat them.  Since saliva contains bicarbonates, which act as a natural buffer against hydrochloric acid, less saliva means higher acid concentrations in the stomach. Alfalfa also appears to have a buffering effect, but whether this is due to its calcium content, specific proteins or a combination thereof is still being investigated.

9.  The physiology of the horse’s GI tract makes it vulnerable to colic.

True.  With an overall average length of 100 feet and the ability to hold about 48 gallons of water and ingesta, the horse’s GI tract must pack into a relatively small space. This is accomplished by a series of bends in the intestines known as flexures.  “Unfortunately,” says Dr. Carr, “these flexures are often sites where food or other materials can slow down or accumulate, potentially leading to colic.  Ingesta can also get held up or impacted in the cecum, the large ‘blind-ended’ pouch that takes food in after it passes through the small intestine, then empties it into the large intestine.” An additional source of potential problems is the rather tenuous way the intestines are held in place. Though it seems surprising, the entire mass filling the abdominal cavity is only anchored to the body in a few places, leaving the intestines vulnerable to displacement and torsion (twisting).

10.  A colicking horse should not be allowed to roll, as this can cause a torsion.

            False. This is another widely believed myth that has been disproved by science. Explains Dr. Sanchez, “A twisted segment of intestine is one of the most painful things a horse can endure.  This typically causes severe rolling, rather than the other way around.”  When a torsion does occur, it is often a complication of gas colic. Gas colic, although very uncomfortable for the horse, is generally not serious and the survival rate is very high. However, complications can arise and become life-threatening if a distended bowel twists or becomes displaced. Such complications are not likely to be caused by the horse rolling, but rather from the fact that the portion of the intestine filled with gas will have a tendency to rise to the top of the abdominal cavity. If rolling were likely to cause a torsion, it would be dangerous for a horse to roll at any time – not just during a colic episode.

11.  Horses with colic will usually have an elevated heart rate.

            True.  Most horses with colic pain will have an elevated heart rate, meaning one greater than 44 beats per minute. The severity of the elevation usually correlates with the intensity of the colic.  Heart rates above 60-70 should be considered significantly elevated and a veterinarian should definitely evaluate your horse as soon as possible.  As individual horses may have a higher or lower heart rate than average, it is important to familiarize yourself with what your horse’s normal resting pulse rate is so that you can tell when it is elevated.

12.  If you think your horse might be colicking, you should try to get it to eat something.

False. Some people believe that feeding a colicky horse will help “settle its stomach”. However, if a horse is colicking, it is recommended that you temporarily withhold giving feed and remove any leftover feed until the underlying cause is known or symptoms resolve. Says Dr. Carr, “If there is a serious problem like an impaction, introducing more feed into the horse’s system can make things worse.  In addition, there are some forms of mild colic that may resolve by simply withholding food and giving one dose of pain relief.  Examples include spasmodic or gas colics, which can occur when the horse ingests too much grain or undergoes a stressful event.”

13. Horse owners should keep pain relief medications for colic on hand, but should consult their veterinarian before administering them.

            True. While it is often recommended to have some pain relievers like Banamine (flunixin meglumine) or phenylbutazone available in your first aid kit, it is very important to consult with your veterinarian before administering them to a colicky horse, as you may mask symptoms important to diagnosis and successful treatment. It is also extremely important that you do not overuse these medications. Banamine, Equiox, phenylbutazone and dipyrone are examples of nonsteroidal anti-inflammatory drugs that are used to control pain in the colic patient.  Repeated dosing of these types of drugs can result in toxicity, including ulceration of the GI tract (which may result in further colic signs) and kidney toxicity (which can result in kidney failure).  These toxic effects can be more severe when a horse is dehydrated or the drug is given multiple times in a single day.  Therefore, when giving these types of medications, it is always best to talk to your veterinarian prior to administration.

14.   A rectal exam is the best way for a veterinarian to diagnose colic.

False. Although the rectal exam is an important part of the work up, it is only possible to palpate 25% or less of the abdominal cavity.  Consequently, the rectal exam rarely results in a definitive diagnosis.  Instead, it is useful to help determine the type of colic (large intestine or small intestine), the degree of distension of the intestine and the location of the affected bowel.

15. A horse that is psychologically stressed is at higher risk of colic.

            True.  Explains Dr. Carr, “Psychological stress brought on by changes in a horse’s physical environment (e.g. trailering, showing, moving to a new stable) or social environment (e.g. any change in herd dynamics, a different neighbor in the next stall, the absence of a buddy) has been associated with an increased risk of colic.  This may be due to physiological changes triggered by stress, or to the fact that stressed horses often go off their food and water.” Either way, doing what you can to minimize such stresses will not only keep your horse happier, but may also help in the prevention of colic.

16.  Allowing a hot horse to drink immediately after exercise can cause colic.

            False. Chances are you have heard the old myth that a hot horse should not be allowed to drink after exercising until it has cooled down. However. recent research has shown that withholding water after exercise may be potentially harmful because it prolongs dehydration, and dehydration can lead to colic, as well as other problems. Horses are more likely to drink soon after exercise when their thirst drive is high, and they need that fluid intake to replace fluids lost to sweating. Therefore, it is a good idea to allow the horse to drink in most typical scenarios. If you want to err on the side of caution, provide access to water that is not ice cold, and walk the horse for short periods between allowing him to have a few good gulps. 


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