Intestinal or gut sounds (borborygmi), are caused by the propulsive action of the equine intestines that contain gas, water and feed.
These rumblings and gurgles are normal in healthy horses, and suggest proper function of the gastrointestinal tract (normal motility). Cause for concern arises when these noises are lessened (hypomotile) or completely absent, or when they are greatly increased (hypermotile).
When assessing gut sounds, I divide the equine abdomen into 4 quadrants: upper left, lower left, upper right, and lower right. These areas roughly correspond to different segments of the gastro-intestinal tract.
To assess gut or intestinal sounds, start by haltering and adequately restraining the horse. Be sure the earpieces of your stethoscope are pointing forward before you insert them into your ears. Make contact with the left shoulder and move down the side of the horse.
Place your stethoscope head behind the last rib and at the mid-height of the abdomen. Listen to the upper left quadrant. Drop the stethoscope down about 8 inches and listen to the lower left quadrant. Record the motility you heard and switch sides.
Listen to the upper right quadrant where gas is often heard since this roughly corresponds to the base of the cecum. Move down to the lower right quadrant. Again, record the motility you heard. Be sure you listen to each individual quadrant for at least 30 seconds. Each of these quadrants corresponds roughly to different segments of the gastrointestinal tract.
I also listen far forward at the lowest point of the abdomen if I suspect that there is sand in the intestine. You may need to wait several minutes for a major wave of contraction in order to hear sand, which sounds like waves breaking on a shoreline, a faint hissing sound.
Tips for safety & Success
The best way for you to know what is abnormal, is to have listened to your horse's gut sounds in health. Listen during feeding time and compare to the middle of the day when there is no feed around. Listen to each quadrant for at least 30 seconds, or even longer. There may be periods of quiet that are interspersed with gut sounds.
There are many ranking methods. I rank motility by number:
0 - Silent, no motility heard during 30 seconds.
1 - Less than normal motility.
2 - Normal motility.
3 - Hypermotile, more gut sounds than usual.
Motility is usually lessened in horses in abdominal pain. Horses that have not been offered feed in hours will also have reduced motility. There will be little intestinal movement in horses that have been sedated with xylazine type drugs.
Be careful, as some horses that are tickled by a stethoscope placed in the fold of the flank may kick.