More than a Gut Feeling – Investigating Colic

In a new series of Horse Welfare articles for this season, our UKPA Chief Horse Welfare Officer, Dr Jo Gale (BVetMed CertLAS MRCVS), discusses colic, what to look out for, and what options your vet will have.

The saying “no foot, no horse” is well known, but an equally good phrase might be “no gut, no horse”. The horse’s gastrointestinal system is enormous and complex – measuring up to 30m in total and suspended within the abdomen by connective tissue. It’s perhaps not surprising that colic is so common in horses and has the potential to be so dangerous.

Most horse owners will have seen a horse with colic. The initial signs can vary but most relate to pain in the abdomen; restlessness, pacing, pawing the ground, sweating, rolling, and looking at – or biting at – the flanks can all be signs, although some horses may simply be listless and withdrawn or just behaving oddly. The colicky horse usually does not want to eat much or even to eat at all. Droppings may be passed as normal but also may be fewer in number or absent and either dry or loose depending on the cause of colic.

Colic is always a reason to call the vet because the cause can vary from straightforward to catastrophic with a prognosis to match. Simple colics include spasmodic colic – the gut becomes over-active causing cramp like pains. More serious causes include impactions (blockages), displacements (movement of a piece of intestine from its correct place to another part of the abdomen where it becomes stuck or trapped), strangulations (where something wraps around the gut cutting off blood supply) and torsions (a twist in the gut itself).

When the vet visits your colicking horse it can be frightening and stressful. In this article I aim to relieve some of the fear by providing information on the checks and tests your vet may do.

Colic cases can be divided into medical (which respond well to drugs and management) and surgical (which need an operation to resolve) and when your vet first examines your horse they will be aiming to decide which of these it is. Sometimes it’s not clear, and after their initial visit your vet may advise you to continue to monitor your horse before a re-examination later or bring them to the veterinary hospital for further investigations. Usually the vet will give your horse some injectable pain relief in this period, not only to ease their distress but because their response to this can be a valuable indicator as to how serious their condition is.

Heart rate and respiratory rate

Your vet will record your horse’s rate of breathing and listen to your horse’s heart and/or take their pulse. Horses in pain breathe more rapidly and have an increased heart rate. A normal heart rate is around 32 beats per minute and in colics can rise to around even 60 or 80 beats per minute. In more serious colics the heart rate can go much higher, signifying serious pain or metabolic disturbances.

Gut sounds

A stethoscope is not just useful for listening to the heart but will also be used on each side of the abdomen to listen for the sounds made by the intestines. It’s normal for the guts to bubble and gurgle as they digest food (these sounds have the cool scientific name “borborygmi”) but in colic these sounds can be increased, decreased or even completely absent. Your vet will mentally divide your horse’s abdomen into four quarters or quadrants and describe the level of gut sounds in each quadrant (left upper and lower, and right upper and lower quadrant).

Rectal examination

It’s the butt of many veterinary jokes (pardon the pun) but there’s a very good reason why your vet may put on the infamous arm length plastic gloves and perform a rectal exam on your horse. Despite the vet’s arm and hand being contained within the rectum, it’s possible for them to feel around the caudal (rear) 1/3rd of the abdomen and identify certain segments of the intestines this way and check whether they are in the right position. It’s sometimes – though not always – possible to feel an intestinal impaction (usually fibrous material like straw but can also be caused by ingested foreign material like string, haynets, plastic bags or sand) or to feel if intestinal loops are dilated due to gas build up. It’s important to note that this procedure does carry risk of injury to both horse and vet and may require sedation and for the horse to be restrained safely in order to be carried out

** Mucous membranes**

The gums and other mucous membranes should be a light/mid pink colour in healthy, well-hydrated horses. In colic they may be normal but can also be pale, white, deep red, blue tinged or even purple, so your vet will look at the gums and note the colour, also noting whether the gums are moist or dry and whether the colour returns quickly to the gums after they are pressed (capillary refill time or CRT)

Abdominocentesis

Often known as a “belly tap” this involves inserting a needle into the horse’s abdomen at its lowest point and collecting a sample of the fluid which sits around the intestines. Analysing this fluid can help to determine the condition of the intestines and whether infection or inflammation is present

** Nasogastric tubing**

Passing a long plastic or rubber tube into one of your horse’s nostrils, up their nose and down their oesophagus into the stomach can be very useful to assess the stomach contents, both the type and amount. It can also be used to pass fluids or lubricants such as mineral oil into the stomach, which should travel into the intestines and may help soften small or simple impactions. Most horses tolerate this fairly well, although it’s not unusual for some blood to be seen as the tube can easily scrape the delicate nasal mucosa

** Other tests**

Other tests such as ultrasound scans and blood tests may be carried out, but these usually take place at the equine hospital after an initial examination.

Many cases of colic resolve with simple medical treatment but a veterinary examination is always warranted as spotting the more serious cases early results in a better chance of success.