Well, last week we intro'd the toes ... and now, let's see how to determine just what is the right LENGTH for the toes ... from the coronary band down to the ground.
If one were to measure the coffin bone (front hooves) of every horse one would see that it measures approximately 3 to 3 1/2 inches from the top of the coffin bone down to the toe.
Now, again, that being said rather simply, there are always exceptions to the rule. The primary focus of trimming a barefooted horse should be that the sole is callused and thick enough to support the impact of the horse's weight during movement. This support is shared with the sole, frog, bars and walls/white line of the hoof. But, to enforce specific toe lengths based on measurements from the coronary to the ground one doesn't take into account that the coronary band/hairline is highly malleable. Any excess in wall or heel length will distort the coronary band/hairline and, therefore, distort the measurement of the toe length. As a result, inaccurate measurements will cause imbalances, thin soles, etc. If the hoof is adequately balanced then the hairline *should* be a relatively accurate starting point from which to assess the length of the hoof toe wall correctly - for the INDIVIDUAL hoof-in-hand on the horse-in-hand. When removing wall height to achieve a correct toe length on an imbalanced hoof as stated, a number of negatives can result i.e.the soles can become too thin thus causing the the hoof to grow more sole, more quickly, and more toe, more quickly and thus, just keep on perpetuating an ongoing issue.
So ... back to measuring toe length. But, gotta talk about the sole again, first. That is also a landmark to assessing a correct toe length for the individual hoof.
A good, solid, healthy sole should measure about 1/2 to 5/8 inches thick. Now, since a health hoof on a healthy horse will be a mirror of the inside foot, we can assume that the bottom of the coffin bone will rest approximately 1/2 to 5/8th inches above ground level. There is your first measurement .. measure the sole thickness to determine just where the bottom of the coffin bone rests!
Easy way to do this ... take a measurement from a straight edge placed across the bottom of the hoof right at the apex. Measure from the straight edge down to the deepest part of the apex of the hoof then ADD 1/2 to 5/8 inches into the hoof (figuratively speaking) ... and that's where the bottom of the coffin bone will be.
Photo Pete Ramey, Reading Sole Thickness.
You can measure again back at the heels with a straight edge across the heel platforms, measure down to the deepest part of the collateral groove at that point and then add 1/2 to 5/8th inch again into the foot and that will give you where the back of the coffin bone is resting. Now you have your ground level start. If the heels are too long, of course, your measurement is not going to be correct; additionally, if the walls are too long then the toe measurement will not be correct. So be sure all is trimmed in a correct and balanced manner and you then have your level from which to measure. This will also help to ensure that your coronary band is not pushed upward which would then distort the toe measurement.
Oh my goodness ... sound like a lot of goobly-gook and most difficult to figure out when trimming. A good, experienced trimmer who understand the anatomy and physiology of the equine digit will have a 'sense' about this and it becomes almost 2nd nature as to the determination of what the individual hoof requires.
Here is a very rough illustration as to how this all fits together - just to give you a rough idea:
Now, if you can imagine the same coffin bone in a very long-toed hoof you can see the recipe forming for a long term issue with white line separation, possible white line disease, imbalanced hoof, possible laminitis and even worse, founder.
It's imperative to understand that the COFFIN BONE is/should be encapsulated in a SOLID, sealed capsule much as a body is in a solid, sealed "coffin" ... nature has a way to protect its own, eh?
Correct toe lengths will help to ensure that solid, sealed hoof.
Gwenyth Browning Jones Santagate is the best-selling author of 10 Secrets to Healthy Hooves as well as a noted author for various international equine publications includingThe Horses Hoof, Equine Wellness, Natural Horse Planet as well as a contributing author for the 2001 United States Federal Mounted Border Patrol Training Manual. For the last 37+ years, she has maintained healthy hooves with natural trimming on thousands of horses and specialized in pathological rehabilitation hoofcare for the last 18 years. She and her husband John keep a small herd of their own equine in SW Florida and continue to offer consults for horses in need. For further information please click here: www.thepenzancehorse.com/2012/RESUME.pdf