Two cases of the ‘incurable’ quarter crack. In both cases, the crack was treated for years by that what exactly had become the initial cause of the problem — the shoeing combined with the unphysiological hoof form (too high heels, too long walls).
On weightbearing, the hoof capsule is supposed to deform in a certain way. This reversible deformation is called ‘hoof mechanism’ and is vital for the whole horse’s organism. (More on the hoof mechanism >>) In the case of these two hooves, the coronet could only bulge outward at the lateral wall but not to move downward (because the sole is fixed by the shoe), as it happens in a physiologically correctly shaped hoof as a part of the healthy hoof mechanism. Over time, an outward crease developed in the wall, starting from the coronet, and right at the last nail, where the weakening of the wall appeared from the hole of the nail. With impact of the hoof contacting the ground, this crease was pushed outward, and with lesser impact (standing on non-weightbearing hoof), the coronet was straightening out somewhat again, drawing the crease flat. This movement prepared the situation for the actual crack to appear, and later it appeared, helped by the weakening of the wall at the last nail hole.
Sadly, the first horse never got a chance to receive the correct hoof care, and ended up in slaughter, giving us now a chance to look closer to the hoof capsule and to learn what certain outward signs suggest about inner hoof structures.
After removing the shoe and trimming the overgrown wall of the cadavier, we are able to see the curve in the while line in the place where the crack starts in the ground contact edge of the wall:
This kind of the curve in the white line suggests, there should be demineralization in the coffin bone in a form of a notch or a groove, which appeared as a result of a certain kind of pressure affected the bony tissue.
Now taking a look inside the hoof capsule, we can see the expected groove in the palmar process of the coffin bone. And we can see the ridge in the inner side of the wall, which was pressing into the bone, causing its remodelling. This is additionally to the more pronounced side bone (lateral cartilage ossification) we see on this side of the bone, caused there by the same reasons as the crack in the wall — the unphysiological forces affecting the hoof capsule and the inner structures:
A similar curve in the white line was found in the second case:
But in the second case, the horse, a warmblood gelding, was luckier. After wearing the shoes for 15 years, prescribed them by vets and farriers as the only remedy against the crack, and bleeding recurrently in the coronet where the crack started from, his shoes finally were removed at age of 18 y.o. and he started receiving the correct hoof care. The correct hoof care began for him from its very important part — providing the horse with species appropriate living conditions, which included free movement 24/7, free access to grazing/hay 24/7 and a herd. His hooves were kept an optimal shape via the physiologically correct trimming, and Nature was able to make the rest via the species appropriate living conditions.
5 months into the rehab, the gelding feels great (the white horse), playing with his buddies:
(Video Ark Equus Ranch for Retired Horses, alHHHC Partner Rehab Center, Germany.)
After 9 months of the rehab, the crack disappeared, the hoof still is improving its shape:
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