Condition scoring is a method of measuring the condition (fat) of a horse. It is the best way to monitor a horse’s weight, and it needs no special equipment. If done correctly, condition scoring works despite conditions which may fool the owner’s eye (such as a horse’s conformation or medical or physical conditions such as a worm burned, pregnancy, grass belly, etc). There are two systems of condition scoring, the European and US versions. The US version is more detailed and is the one covered by this article.

Steps

Get your horse to stand so that it can be examined. Be sure you know which parts you'll be feeling.

Feel along the neck. Run your hand along the area that is usually covered by the mane. Does the neck connect with the body smoothly, or is it bony or fatty in this region? Determine whether the bones are visible or just palpable. Can you feel or see any fat or a crest?
Run your hands along the withers. Feel for bone structures and fat; don’t be fooled by prominent withers, which is due to conformation, or muscle wastage, which is probably due to an ill-fitting saddle.
Move onto the shoulder. If very fat the horse will also have fat deposits behind the shoulder. Is the shoulder smooth? Can you feel or see any fat or bones?
Explore along the ribs by stroking in the direction of the rib with the flat of your hand. At one extreme, the ribs may be protruding; at the other extreme, the ribs are so cushioned in fat that they can't even be felt.
Examine the back by putting one finger on the spine and watch whether your other fingers are above, below or level with that one. Is there a groove along the spine or is it level? How visible are the vertebrae?
Ask someone to hold the tail to one side while you stand behind the horse. Look at the shape of the quarters and the space between the inner buttocks. Feel for bone structures and fat deposits. How much space is there between the buttocks? Are the quarters round or diamond-shaped?
Rate each part according to the table below. Get the average score by adding together all the scores and dividing by six.

Condition Neck Withers Shoulder Ribs Back Quarters
Score 1 (Emaciated) Bones visible Bones visible Bones protruding Bones protruding Bones protruding Individual vertebra can be seen Hips protruding, making quarters look diamond shaped; Large gap between buttocks
Score 2 (Very Thin) Bones easily felt Bones easily felt Bones protruding Bones protruding Bones protruding Hips protruding making quarters look diamond shaped; Large gap between buttocks
Score 3 (Thin) Bones can be felt Bones can be felt Can’t feel any fat Ribs can be seen Some fat can be felt either side of spine Loins and inner buttocks filled in but no obvious fat
Score 4 (Moderately Thin) Not overly thin Not overly thin Not overly thin Faint outline can be seen Spine slightly higher then sides The quarter has some fat but dip in
Score 5 (Moderate) The neck joins the body smoothly Have a rounder appearance Front of shoulder has a smooth appearance Rib can be felt easily Back level Quarters filled out some Some flesh on inner buttocks
Score 6 (Moderately Fleshy) Some fat can be felt Some fat can be felt Some fat can be felt Ribs can be felt Back level Quarters rounder
Score 7 (Fleshy) Fat can be felt Fat can be felt Some fat behind the shoulder Can be felt, can also feel fat in between ribs Slight groove along the spine Small space between buttocks
Score 8 (Fat) A crest begins to form Fat fills out either side Behind the shoulder has a smooth appearance. Difficult to feel Groove along the spine Smooth appearance to hip
Score 9 (Obese) The neck has an obvious crest Bulges fat Bulges fat Can’t feel Obvious groove along the spine No space between buttocks

Tips

Score 4 (moderately thin) to score 6 (moderately fleshy) are healthy. The ideal weight for a horse will depend on the management and workload. A racing or event horse will likely be score 4 while a dressage or show horse will be closer to score 6.
Condition score every 2 weeks and plot your horse’s score on a graph. This can be used with or without a weight tape, but condition scoring is more precise.
Taking photos regularly will also help keep track of your horse’s weight, and are especially helpful while learning to condition score.

Warnings

Never stand directly behind a horse. To view the horse from behind, stand well back out of a range of a kick. Don’t underestimate a horse’s reach.
Stallions, and occasionally geldings, have a crest. This is due to hormones, not fat.
Condition scoring is a measure of fat, not fitness.
Use your hands as well as your eyes.
Condition scoring can only be partially taught, as proficiency with this type of scoring comes mostly with experience. You will become more accurate with practice as you learn what a horse should look and feel like.