Impaction Colic

What is impaction colic?
Impaction colic occurs when a blockage develops in the intestines, usually at the pelvic flexure. This is because at this site the large intestine changes size significantly and goes around a bend. Impactions can be small eg the size of a grapefruit or can involve several feet of the intestine. The impaction is usually made up of poorly digested fibre although sand can cause a special type of impaction.

Causes

• Increased fibre in diet -especially a sudden increase
• Reduced drinking – this can be common when troughs are cold
• Poorly chewed fibre – older horses and horses requiring a dental
• Horses not moving around as much – increased stabling or horses huddling behind a hedge or barn to keep warm may not exercise as much.

Signs to look for that may occur prior to colic

• Reduced faecal output with smaller, harder, darker faecal balls, sometimes with mucous on them.
• Reduced water intake
• Reduced food intake or a change in eating behaviour

Early colic signs

• Quieter than normal
• Picking at food
• Lying down more than normal
• Playing with water

Colic signs
Whilst there are not specific signs for different types of colic, impaction colic often begins with low grade pain. Horses may be seen lying down more than normal. Standing stretched out or lying stretched out making occasional groaning signs. They may still be eating at this point but as more food packs up against the blockage the intestine is stretched which becomes violently painful. In severe cases your horses gut can rupture, causing them to go into shock resulting in a high risk of death. 

What should you do?
If you suspect your horse has even mild colic, you should arrange for them to be seen as soon as possible.

• Don’t allow your horse to eat but they can drink if they wish to.
• Monitor your horses faecal output.
• If your horse wants to lie down, ensure they have somewhere safe to do so.
• If your horse will walk gently this is one of the types of colic this is beneficial for.
• Decide if you will be willing to send your horse to a referral facility if it is recommended. If so ensure you have transport ready.

What your vet will do?
Your vet will perform a colic examination on your horse. This may include all or some of the following and may require sedation. Particularly if your horse is sore.

• A general examination eg heart rate, respiratory rate, temperature and check colour of mucous membranes and capillary refill time (a measure of dehydration).
• Listen to heart, lungs and gut sounds.
• Perform a rectal examination
• Pass a stomach/nasogastric tube
• Adminstration of fluids +/or laxatives via the stomach tube
• Adminstration of fluids through an intravenous catheter.
• Testing the faeces for sand – you can do this yourself and should do if you feed your horses hay on the ground and they are kept on sandy soils (see below for method).
• Take a blood sample to measure levels of dehydration and possibly white blood cells to check for infection.
• Perform an abdominal ultrasound examination
• Collect fluid from the abdomen.
• Administer pain relieving injections if they have identified the type of colic involved.
• Refer your horse for further diagnostics or for treatment.

How to test faeces for sand:

1. Take a rectal glove or clear plastic bag.
2. Place a faecal ball and water in it.
3. Crush up the faecal ball in the water.
4. Hang up the glove – fingers down
5. Hang the plastic bag at an angle with 1 corner lower than another.
6. Check in 30m and sand will have either settled into the fingers of the glove or the corner of the plastic bag.

If your horse has a mild/small impaction they can often be treated at home by your vet

• Pain relief
• Withholding food especially long fibre
• Administering fluids by nasogastric tube with or without intravenous fluids – This may require several visits depending on the size of the impaction
• Regular assessment of horses heart rate and level of hydration
• Monitoring of faecal output
• Small wet feeds containing salt.

If your horse has a large impaction referral for oral and intravenous fluids will be recommended, in some cases, surgical emptying of the impaction may be required. This will be discussed further by your vet if required.