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Previously, we have discussed small intestinal colic and gastric ulcers.  However, when discussing colic, we have to determine if it is small intestinal in origin or large intestinal. 
Below is a brief list of problems associated with the large colon.  Typically, these are non-surgical and can be resolved with some medical management.  That's not ALWAYS the case, but for the most part it is.  (Part 2 will focus on more severe types of large intestinal colic.)

The large intestine begins as the ileum (the last section of the small intestine) enters the cecum and is approximately 40 feet long.  The cecum is a blind sac that is shaped like a "C" and is a big fermentation vat.  The curvaceous colon then takes a bunch of twists and turns after it exits the cecum.  First, it becomes the right ventral colon.  It changes into the left ventral colon and takes a big, narrow turn (the pelvic flexure) into the left dorsal colon.  It then turns again to become the right dorsal colon.  But we're not done yet!  From here, the intestine narrows into the small colon and finally the rectum, which is the last foot or so of the colon.  Whew!  With all of that crammed into a space about the size of a 33 gallon trash can (along with all the other organs!), what could possibly go wrong?  Let's find out!
Gas/Spasmodic Colic:  With all of the fermentation that goes on within the large intestine, a lot of gas is produced.  Occasionally, the colon can become a little distended and uncomfortable.  These will often correct themselves with a little bit of time and maybe some pain meds.  Please remember to contact your veterinarian and discuss this with them, as it could be something more serious.  Sometimes, simply walking horses for a bit can help things move along and uh, expel the gases.  Just remember, we want to walk them for a bit then let them rest.  Walking non-stop does nothing more than exhaust yourself and your horse. 

PicturePelvic Flexure (
Impactions:  Another common finding are pelvic flexure impactions.  These occur because this is an area of the LI that narrows significantly.  When horses become a little dehydrated, the feed material binds together more easily and gets stuck.  We find these happen more frequently during cold weather as horses tend to drink less. 

Other types of impactions include cecal impactions, where a large amount of feed material becomes trapped within the cecum, and small colon impactions, which tend to be more common in miniature horses.  These can be more difficult to treat, but still follow the same pattern as pelvic flexure impactions. 

The mainstay of treatment for any of these is fluids, fluids, and more fluids. Absolutely no food should be given to horses with an impaction (or any colic for that matter), as it will continue to build up and make the impaction harder to move.  Many times we can pass a tube and administer oral fluids to get everything moistened up and moving again.  Other times, we may need to re-hydrate the patient with a combination of IV and oral fluids.  Occasionally, these can become severe enough to require surgery. 

Horse in sandy pasture
Sand Colic:  Sand colic occurs when horses are fed on sandy ground.  As they eat their hay, they also take in sand particles.  This sand then sediments out in the ventral colon and sits there.  While laying against the wall of the intestine, it can cause severe irritation and lead to diarrhea. The more that builds, the more uncomfortable they can become.  The sand can even become impacted, which may require surgery.  The best bet for these is prevention, by either feeding in a hay feeder or placing a rubber mat over sandy ground and feeding on that. 

If you're not sure if your horse has ingested sand, here's a simple way to find out!  Grab a couple of fecal balls (make sure there's no obvious sand stuck to them) and put them in a ziploc bag.  Add water and mash up the fecal balls.  Then hang the bag on an angle, so one corner points down.  After 5-10 minutes, come back and check it.  The sand, if present, will sediment into the corner of the bag.  Sometimes you can see a thin layer of it, other times you nee to squeeze the corner between your fingers and feel the gritty texture.  If you notice any, you may want to consult your vet for treatment options and consider changing where/how you feed.
As already mentioned, if you think your horse is colicking, all food should be pulled.  We don't want to make a bad situation worse.  Horses can be off feed for quite a long time with few ill effects.  The next thing to do is contact your veterinarian.  We don't recommend administering medications prior to calling.  This is because if we do need to come out, medications can mask signs that might help with a diagnosis. 

Stay tuned for Part 2 where we'll discuss more serious and surgical types of large intestinal colic. 
Colic is a scary word to horse owners and veterinarians.  However, some types of colic are much worse than other types.  While 90% of colic cases resolve with minimal treatment on the farm, some require more intensive care.  One such type of more serious colic  is small intestinal strangulation, which is an obstruction of the blood supply and the lumen (the inside of the tube, where food passes through) of the small intestine. 
GI Anatomy1. Stomach 2. Small intestine 3. Cecum
The horse's gastrointestinal system is quite lengthy - it spans approximately 120 feet, and the majority (70-80 feet) of that is small intestine.  Furthermore, it's mostly floating freely in the abdomen, with minimal attachments to the body wall and surrounding organs.  This conformation gives lots of opportunities for something to go wrong, whether that's a twist, or some other way that the intestine ends up in the wrong spot. 
The small intestine (or SI, for short)  is the same in horses as it is in dogs, cats or humans.  It's made up of 3 segments - the duodenum, the jejunum and the ileum.  The duodenum is the first section, just after it leaves the stomach and for about the next 12-16 inches (that's it - so, not much goes wrong with the duodenum!)  The jejunum makes up the bulk of the small intestine, and the ileum comprises the last foot or so before it enters the cecum.  There are minor variations in these structures, but we don't have to worry about them here.  All this SI is suspended within the abdomen by a sheet of connective tissue called "mesentery".  (If you laid a garden hose straight across a towel, then picked the towel up at all 4 corners it would create the same effect.)  The mesentery brings blood supply to the intestines. 

The equine digestive tract is always a concern for horse owners - and veterinarians!  Colic can be caused by many different things, and one possibility is EGUS - Equine Gastric Ulcer Syndrome.  Gastric ulcers are actually quite common in horses.  There are a variety of reasons for this, but have no fear!  While they are common, they are rarely life-threatening and can be cured with appropriate treatment.
First, let's start with an anatomy overview.  The equine stomach is divided into two sections - the non-glandular (or squamous) section, and the glandular area.  The line dividing these areas is known as the "margo plicatus".  Stomach acid is secreted by the glandular area.  We typically see ulcers along the margo plicatus on the squamous side of the stomach, but we can also see ulcers throughout the non-glandular and glandular regions.  Oh yeah, and just to be clear, gastric ulcers are erosions in the normal lining of the stomach.  Pretty simple so far, right?

The eye is a very delicate organ, and horses specifically have eyes which are in a very precarious position.  In order to allow for a nearly 360 degree view around them, horse eyes are placed well on the outsides of their heads.  This anatomic location combined with a horse's normal "flight" response makes eye injuries quite common.  One of the most common things we see are corneal ulcers. 

Every so often it happens – your horse just doesn’t seem right and you need to call the vet.  When you do, it’s important to have as much information as possible so your vet can get a good picture of what’s going on.  Here are five of the most common questions we ask horse owners – know these, and you’re one step ahead of the game!

With the warm fall we've been enjoying, it may be hard to remember that winter is just around the corner.  Soon enough, however, we'll be battling snow and frozen ground as we take care of our equine companions.  It's important to put some thought and time into preparing your horse and your property before winter sneaks up on us completely.  We've outlined a few things to keep in mind to help this transition time be as seamless as possible. 

Recently, mosquitoes infected with EEE (Eastern Equine Encephalomyelitis virus) were found in Voluntown, CT.  Not only that, but there have been 2 confirmed cases of EEE positive horses in Massachusetts.  While it would be nice to hide from it, the fact is that it is in our backyard.  But what do we really know about it? 
USDA map Oct. 2012
EEE is mainly found in the US east of the Mississippi river, and throughout areas of Central and South America.  The virus persists in “reservoirs” – wild animals that carry the disease such as bats, rodents, and birds.  A vector (such as a mosquito) becomes infected when it feeds on one of these animals.  Most often, EEE is maintained through a transmission cycle between birds and mosquitoes.  The mosquito then carries the virus for life and can transmit it through its saliva.  If a horse happens to be the source of the next blood meal, then they can become infected and quickly begin to show signs. 

Once infected, it takes approximately 5-15 days for signs to show up.  These signs can be very mild such as a fever and depression; or severe including blindness, stumbling, seizures or death.  Any neurologic signs could be indicative of EEE, however other diseases such as rabies must be considered as well, and a diagnosis should be confirmed via testing.  Unfortunately, a diagnosis is often obtained post-mortem.  If EEE is suspected, the state veterinarian must be contacted and the disease needs to be reported.

When it comes to the equine eye, we often discuss common diseases such as corneal ulcers, conjunctivitis or uveitis.  We do treat these conditions quite a bit, however there are some  serious uncommon diseases that we do have to think about when considering an inflamed eye.  One of these diseases is glaucoma, which can be set off by any of the above listed issues, or by another underlying problem.

This time of year, it's good to be a horse vet.  The weather is delightful, and we get to see lots of healthy patients for routine things - vaccines, dentistry, reproductive work.  Foals have been arriving for a few months now, and you have to admit, there is not much cuter than a newborn foal.  Cuteness aside, however, deciding to breed horses is a big decision, and not one to be taken lightly.  If this is something you have been considering for your mare or stallion, read on.

Feeding off of our last post on nutrition (pun intended), we thought we would talk briefly about the amount that horses are fed.  When talking to clients about nutrition, we often ask "How much are you feeding your horse?"  Usually the answer is something along the lines of  "A half a scoop twice a day."  But what exactly is a scoop and is it an appropriate amount to be feeding? 

Scoops come in a variety of sizes, and we use the term pretty loosely.  It can be applied to anything from a 1/2 cup measuring cup, to a #10 coffee can, or even a shovel!  That can make it difficult to communicate to your vet  exactly how much you're feeding.  Knowing the volume of your scoop can be helpful, however different feeds have different densities.  One scoop of sweet feed does not necessarily equal one scoop of pellets. 


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Twin Pines Equine Veterinary Services, LLP