Tests or procedures used by your vet to determine what is wrong with your horse, in order to reach a diagnosis.

Cost: $100 to $500

These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.


Ultrasound, Trans-Abdominal for Colic, Generally

Cost: $100 to $500

These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.


Ultrasound is extremely useful for imaging the horse's abdomen in cases of abdominal pain or suspected abdominal disease.

Ultrasound produces sound waves that pass through the tissues and bounce back to the transducer at different speeds, depending on the density of the tissues it passes through. This pattern is converted into an image by a computer.

The hair is wet well with alcohol to allow the ultrasound beam to penetrate the hair coat. The ultrasound probe is placed in particular locations and through a particular exam sequence to visualize the accessible structures. Horses with heavy coats may need to be clipped. The size, location and tissue appearance all are evaluated.

The left and right kidneys, liver, spleen, stomach, small intestine, large intestine, bladder, body wall, peritoneal space can all be evaluated to some degree. Findings might include increases in wall thickness indicating swelling, abnormal positioning of a particular segment, overfilling (distention) with gas or fluid. In addition, peritoneal fluid amounts and character (cellular, clear, containing debris) can also be determined. Normal peritoneal fluid appears black on ultrasound- clear fluid.

Why A Vet Chooses This Diagnostic


Diagnoses Your Vet May Consider

This test could rule out or confirm any of the following diagnoses.

Very Common
Less Common
more diagnoses
Ultrasound is a fast and noninvasive test that allows a detailed view of soft tissue structures.

Easily differentiates fluid from different tissues and may show intestinal movement in real time, which can be very helpful.


Even the most powerful, penetrating ultrasound machines and probes can only penetrate about 40cm into the abdomen - about 15". Most give good resolution at only about half that. Because of this, much of the abdomen cannot be visualized.

Lower power machines with high frequency probes may only penetrate a few inches and provide limited information.

Ultrasound cannot penetrate gas (air) or bone. If the intestine has large amounts of gas in it, it may block the ultrasound beam from deeper structures.

Some horses and donkeys have thick abdominal fat. Fat can interfere with the ultrasound's penetration, and may limit it's usefulness in a particular patient and case.

your role

Questions To Ask Your Vet:
  • Would ultrasound add to your diagnostic understanding of my horse's abdominal disease?

further reading & resources

Author: Doug Thal DVM Dipl. ABVP