Hoof Angles

by Yvonne Welz ©2006

Why are Dr. Strasser's toe angle recommendations about 45 degrees for front hooves and about 55 degrees for hind hooves? These measurements are taken from the coffin bone itself.

"The hoof capsule can be considered a 'cast' produced by the living tissue (corium) surrounding the coffin bone and lateral cartilages. Therefore, it must have the same angles as those of the coffin bone: about 45 degrees for a front hoof, and 55 for a hind. These angles are based on hooves with sharp toes, not rolled, rounded or abraded ones." -- Dr. Hiltrud Strasser, The Hoofcare Specialist's Handbook, page V-9.

These photographs are not perfect demonstrations, though I laid flat out on the ground to take these photos of coffin bones, from Dr. Strasser's personal collection. There are usually a couple degrees of distortion involved in photos, so it is best to measure in person.

Measure actual coffin bones for yourself. When the bottom is ground-parallel, the front edge of the coffin bone will be very close to that specified angle -- they will all be close to 45 or 55, off by maybe a degree or two for the fronts, with a wider variance for the hinds. The hoof is simply trimmed to follow the internal structures. These measurements are the same for every horse, because their coffin bones do not change. The front and hind coffin bones have very different angles, so the outside hoof should reflect that difference.

Now how does this apply to the outer hoof shape? Here is a correctly-trimmed front hoof below, with the plexi lined up with the 30 degree hairline on this hoof. When the hairline is 30 degrees, the coffin bone sits ground-parallel. The hairline angle is measured in a straight line between 2 points -- from the lowest part of the front of the coronet, direct to a heel hairline point right under where the lateral cartilage dips downwards. This is important to keep in mind, as many hairlines are not straight, or dip down in either the front or the back. This hairline happens to be very straight. This toe angle is parallel to the 45 degree line on this plexiglass square. This horse is sound and ridden.

Above: Front Hoof with 30 degree hairline and 45 degree toe angle.

Below is a hind hoof demonstrating correct angles. The 55 degree angle line on the plexiglass square is parallel with the toe on this hoof (photo is taken a little above, instead of straight on). This horse is also sound and ridden 10 miles plus per day.

Above: Hind Hoof with 30 degree hairline and 55 degree toe angle.

How to Measure

First we have to make sure the hairline is exactly 30 degrees before measuring the toe angle of a horse. Actually, what Dr. Strasser says is that in healthy hooves, there is a 105 degree angle between the toe wall and the hairline on front hooves (95 degrees on hinds). So if the hairline is not 30 degrees, of course the toe angle will be off by the same amount that the hairline is off.


105 degrees for Front Hooves and 95 degrees for Hind Hooves, drawing courtesy Dr. Strasser & Sabine Kells.

Some people believe (though nowhere has any coffin bone position been proven or substantiated in any way) that horses should not have ground-parallel coffin bones, and that instead the coffin bones should be angled at 5 degrees or more, with the coffin bone pointing downward on its tip. When this condition exists, the hairline angle will be off by whatever amount the coffin bone is tipped, and the toe angle will correspond with that. Therefore, it is impossible to compare toe angles between horses that have ground parallel coffin bones (30 degree hairlines) and those that do not. There can also be a question as to whether the coffin bone is actually ground-parallel under full load, or while unweighted, which can make the 5 degree discrepancy non-existant.

Measuring the hairline: the hairline angle is NOT measured by averaging the line of the hair. The hairline angle may not even touch the hairline, believe it or not. The hairline angle is measured between two points, the first point is the lowest spot at the furthest front of the hairline at the toe. The second point is a spot at the heel hairline which is right below where the lateral cartilage dips down. The healthier hooves have straighter hairlines, but many hooves have places where the hairline dips sharply at either the front or the back of the hoof. In those cases, you literally ignore the main part of the hairline to get the correct measurement. Many photos do not clearly show the heel area, so it can be hard to know exactly where that heel spot is on a particular hoof. You really have to measure in person, not from a photograph.

Measuring the toe wall: in hooves that are naturally worn, horses that are ridden over abrasive terrain, etc., you cannot really measure the toe angle from the bottom of the hoof if you really want to be accurate. It would be better the measure the angle between the hairline and top of the toe wall growing out, and see if it is 105 degrees (or 95 for hinds) first. Then measure from the side using only the top inch of hoof below the coronary band. We are not trying to include any kind of breakover or natural wear in this measurement, so the angle of the toe wall is measured from the top, not from the bottom, if there is a difference between the two. Also, do NOT include any slippering of the bottom of the hoof when you measure toe angle. If you do include natural wear in the measurement, there is a wider range:

"Front hooves should be 45-50 degrees, hinds 50-60, and the coronet/ground angle should be about 30 degrees."--Dr. Hiltrud Strasser, Lifetime of Soundness, page 131. This toe angle range was given to account for natural wear and abrasion if measuring from the coronet to the bottom of the toe where it touches the ground.

"A horse on abrasive terrain rounds (and as such thins) the lower part of the hoof wall; this natural wear can extend far up the hoof, resulting in a steeper angle than would at first glance seem proper." -- Dr. Hiltrud Strasser, The Hoofcare Specialist's Handbook, page V-9.

Here is an assortment of photos of sound, ridden horses with angles fairly close to correct, as defined above. We recommend that people do not focus so much on the toe angle, but instead pay more attention to the hairline angle. Most sound, healthy horses trimmed in any method will have close to 30 degree hairlines. Please do not force the angles! Trim the hoof, observe the horse, and observe the angles.

 

Front Hoof

Front Hoof

Hind Hoof

Front Hoof

Front Hoof

Front Hoof

Front Hoof

Front Hoof

Hind Hoof

Front Hoof

Front Hoof

Front Hoof

"Obviously, these 'correct dimensions and proportions' are not a blueprint which can be precisely applied to every hoof. Aspects such as breed and terrain, as well as individuality, will cause a degree of variation. However, sound hooves of all breeds, whether belonging to a mustang, wild-living warmblood breeding stock, or a horse of the Mongol nomads, share certain aspects which are determined by anatomy, physiology, and the laws of physics." -- Dr. Hiltrud Strasser, The Hoofcare Specialist's Handbook, page V-9.


 

Do toe angles really matter?
There is a slight bulge in this hairline above (healthy front hoof), which is being gently addressed - but this is a 30 degree hairline measured from toe point to heel point. The very tight, correct toe wall, with absolutely no flaring to it, definitely measures 49 degrees. Healthier feet seem to have steeper toe angles, while retaining 30 degree hairline angles. Natural wear might easily account for this.

©2006 by The Horse's Hoof. All rights reserved. No part of these publications may be reproduced by any means whatsoever without the written permission of the publisher and/or authors. The information contained within these articles is intended for educational purposes only, and not for diagnosing or medicinally prescribing in any way. Readers are cautioned to seek expert advice from a qualified health professional before pursuing any form of treatment on their animals. Opinions expressed herein are those of the authors and do not necessarily reflect those of the publisher.


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