Hello FoxRider! My name is Kate Wilson – I am a Qualified Saddle Fitter certified by The Society of Master Saddlers. My business is Dutchess Bridle & Saddle LLC and I travel all over the upper Mid-Atlantic and lower New England area for on-site saddle fitting. I wanted to throw my hat in the arena with a few other thoughts for stabilizing your saddle on your young horse.
Fitting young, underdeveloped horses is always a challenge. I would not recommend getting a fully custom saddle built at this point in time as you cannot predict how and when the horse will change. Most saddles can be altered along with the horse however, this can get expensive and the saddle will need to be worked on causing lengthy downtime. In discussing saddle fitting on young, just-in-work horses, I usually recommend getting either a well fitting used saddle or shimming/padding a saddle that you already have that fits as well as can be.
There are some basic elements to your problem that fit directly together. You mentioned using a saddle on her that is meant for a broader withered horse. I can see from the first picture that the withers have some height and the base of the withers (approximately 6″ down each side from the spine behind the shoulder) is not that broad. Typically, rubbing under the cantle area is a signal that there is a lack of stability in the saddle. This usually begins in the pommel area and physically manifests the instability in the back portion of the saddle. When a tree is too wide, the tree points are not parallel in angle to the horse’s wither shape. When this happens, the underside of the pommel sits too low to the top of the withers (diminished clearance) and the top inside of the panel is too tight on either side of the withers. You won’t get bridging in this scenario. With the pommel too low, the back end will lift off the back just enough to either fishtail side to side or pop up and down – this is especially apparent in the trot phase (not seen as much in walk and canter when the rider stays seated). When the cantle area moves, it scrubs the saddle pad against the horse’s back causing the hair loss. It won’t necessarily have heat as it is a friction rub and not a pressure point. The pressure points in this scenario will be located under the pommel closet to the gullet of the panel and under the stirrup bars.
The only two things I can’t tell from the photo of the horse on the lunge line is the placement of the saddle in relation to the back edge of the shoulder blade and also how the saddle is billeted. It’s not easy to say but it looks like the saddle may be either placed too far forward or it slid forward. Usually with a saddle that’s too wide, they have a tendency to slip backwards (pommel tipped down with a point billet drags it backward). You did say that you felt the balance was tipped back with little clearance between the cantle gullet area of the saddle and the spine – this would indicate to me that the saddle is being placed too far forward onto the back edge of the shoulder blade. This will make the pommel higher than it should be and can result in bridging. Depending on the positioning of the billets on the saddle, I see clients placing saddles too far forward in order for the billets to line up with the girth. It is the tree of the saddle needs to be behind the shoulder. The tree points can be located by the line of hardware (headnail, falldown D and saddle nail) that secures the seat’s skirts and the top of the flap or the point pocket underneath the flap. If the saddle has a large thigh block covering the tree point pocket, use the line of hardware. Make sure this line of hardware is behind the shoulder blade. If this placement now puts the billets too far back, you may need to use an off-set or anatomical girth that places the buckles backward and the main body of the girth forward. Also, if the saddle you are using has a point billet, this pull pull a saddle that is fitting too wide more down in the front adding to the instability.
Although shimming the rear of the saddle seems logical because that’s where the physical manifestation of the pommel not fitting correctly is showing, it’s not the area that needs correcting. The pommel area needs to be lifted and this will, in turn, make the cantle area more stable and have more contact with the horse’s back. However, if you are concerned about diminishing the clearance over the spine underneath the gullet of the cantle area of the panel, a wool or Thinline style pad would give you the all-over lift you will need for clearance over the spine. I am not a fan of the Thinline shims but prefer to use the Mattes PolyFlex shims for all shimming applications. I cut them in thirds and layer them so that at the bottom on the front pocket, there are three layers, the middle layer is 2 layers and then the top closet to the top of the withers is one layer. This way, you are filling in the gap underneath the tree point and supporting it so it is more stabilized and takes some pressure off the top inside of the panel. You can also use more of less graduated layers on one side versus the other for an asymmetrical shouldered horse.
I hope this tips have been helpful!