Step 1:Locate the hair-line at the heel and at the top of the hoof wall at the front of the foot.
Line up the "coronet" line (30°) of the plastic sheet connecting these two points.
Step 2:Keeping the "coronet" line (30°) between these two points, it is moved until the front foot line (45°) lines up with the dorsal hoof wall. The breakover of the shoe must be well behind this point to prevent the dorsal wall from being separated from the pedal bone (P3). The base edge of the plastic sheet indicates the angle of the base of the pedal bone.
Step 3:To get an indication of how much heel to remove, draw a line across the sole about 1cm back from the point of the frog and mark the side wall at each end of the line. The measurement is taken from where the sole blends into the frog – the "true point of the frog".
Step 4:Keep the 30° line on the coronet and slide the plastic sheet back until the bottom edge of the plastic sheet lines up with the mark on the side of the hoof wall.
The foot would have to be trimmed to this angle to give the a ground parallel pedal bone (the solar edge).
How much the farrier will trim will depend on a number of factors:
- How quickly he feels he can de-rotate the foot.
- How much foot there is.
- The estimated thickness of the sole.
- Whether there is prolapsing of the sole under the tip of the pedal bone.