Huge debate between reining trainer (who is a farrier) that owns the facility and outside farrier. FEI horse working I-1 is twisting on Left hind during strike off. Trainer says too much/high inside heel. Farrier says hoof is balance for leg conformation (he has been doing horse for 6 years). Horse has never been lame. Just had first hock/stifle injections. The two people are friends, but disagree substantially regarding hind shoeing. Both are very well-respected and knowledgeable. Needless to say, the situation is has gotten very uncomforatble for owner of horse. What say the knowlegeable people on this forum?
That the 6-year veteran farrier is right but for a couple of interesting reasons.
Most of the time, "twisting" during any part of the weight-bearing phase of the strides comes from a rotational deviation in the hock. That means the brick-like bones composing the hock transmit force from the ground to the hip in a cork-screw fashion. The hock appears to "wring" from inside to outside as the horse steps off that leg.
It may also be that there are angular deviations in other bones from cannon bone to the ground. This means that the lateral and medial sides of these bones (especially the long ones) are of slightly different lengths.
The angular deviations are problems but also "normal" and part of the way that we have bred WBs to be base-narrow. Ideally, these horses narrow from hip to hock and then go straight down to the ground. This helps the horse reach in (medially) with each stride and support his weight without too much muscular effort. Many of them do, however, have cannon bones that are slightly longer on the lateral side.
Back to shoeing:
Base-narrow horses, especially those with rotational deviations in the hocks, can crush the outside heal and/or slow its growth.
In theory, you could trim the heels to be even at each shoeing. And yes, I don't think you want to "build in more cork-screw action" by raising the inside heel. But the lack of growth on the outside one will never give the farrier much to trim. And even if he dutifully shortened the inside heel at each appointment, it would grow more in between them.
So did the original farrier fubar this horse all up? I'd guess not any more than the horse's conformation and kind of hoof growth already did.
Assuming the horse is older and sound working at his level, I would not mess with the shoeing. Hock injections are common for horses doing much less strenuous work. I wouldn't use the new need for these as a sign that shoeing is going awry. As horses age, their hooves narrow, especially behind the quarters. The farrier might find himself wanting to find a way to protect and support the crushed or slow-growing lateral heel and quarter.
If it is has the horse recently gone up a notch in competition?
To re-establish the peace maybe a third or fourth opinion is required. Seek out the best and get their take.
Worried about impeding doom? If money is no object spend $$$$ on vet exams/diagnostics (x-rays, bone scans, etc) to look for problems now and then plan to compare results in 3-6-12 months.
I've known a couple horses that have always had a slight twist on one hind but they've held up fine in demanding training and competition (prelim event horses). For one horse, as far as I know, the twist never improved or got worse as the horse moved up the levels. And that horse recently vetted clean.
Sometimes is can be due to a longer inside heel than outside heel, but not always. Has the farrier suggesting this looked at the horse?
The couple horses I have trimmed who have twisted the hock have both had high inside heels. But it's only been two horses that I did for friends. These horses were also barefoot, so it was very easy to trim a little off the inside heel and then walk the horse forward to check the twisting.
Even if the hoof is perfectly balanced for the static limb it may not be balanced for efficient motion, or motion in your particular footing.
If what is being tried isn't working try something else.
My own experience(farrier) is that due to hind hooves wanting to break medially and land laterally sometimes what needs to be addressed is the medial toe and/or lateral heel.
In soft arena footing if there is to much sink laterally(heel) from landing the medial toe ends up with "float" and the hock wobble can be a result of the hoof having to pivot down the lateral wall, and around the lateral toe before the medial toe finally can dig in a pivot up. The hoof is basically sinking in a rotational fashion so it show in the hock.
Does your horse's hock wobble on firm footing also?
If only in soft footing you either need to add lateral heel float or if barefoot have a strong bevel applied to the medial toe.
Go here: http://www.barefoottrim.com/2007/balance/balance.htm
That gives some 'landmarks' to go by to assess the balance of the hooves. I would tend to agree with your trainer. Had a little World Champion Mini who twisted when he came here. Doesn't twist anymore (and is still a World Champion.) In fact, the gal who owns him also has several other and they all are World Champions. If I remember correctly they all twisted a bit in one hock or the other when they came here. It was balance. Nothing more. As Bumblebee noted, check the diagonal balance particularly.