The horse’s back (loin) area is a good indicator of the horse’s condition. In a healthy horse, the spine is level and there is no crease along the back. At a condition score below 5, the spine will be prominent and a crease will start to appear. Fat will begin to accumulate in the loin area as the condition score increases above 5. The withers and ribs are other good indicators of a horse’s condition.
When a horse’s flanks collapse, it is often due to a low energy/protein diet. Collapsed flanks can also be caused by a lack of muscle. Adding exercise that requires the horse to rock on to its back end and push off the ground, such as bouncing exercises, can help build muscle.
Another common cause of collapsed flanks is excessive feeding of hard feed. Horses should not be fed more than one kilogram per 100 kg of body weight of hard feed each day. A horse that receives too much hard feed will have to work very hard to digest the food and will not have any reserve to take in additional feed when it is needed.
A horse that is prone to collapsing flanks can be helped by feeding a low fiber, high protein hay or alfalfa based feed. This type of feed is easier for the horse to digest and will prevent sand accumulation in the stomach.
If a horse has a recurring problem of collapsed flanks, it is important to monitor the horses’ respiration rate. This can be done by observing the rise and fall of the ribcage area, or more accurately, by palpating an artery to feel the pulse of blood flow. A good method is to place your middle finger and either the index or ring finger on the artery located under the jawbone, the radial artery at the inside of the knee, or the digital artery at the fetlock. Count the number of heartbeats that you can feel in a thirty-second period and multiply by two to find the horse’s normal breathing rate.