The ornamental design for saddle pad, as shown and described.
FIG. 1 is a perspective view of the top, front, and right side of the saddle pad;
FIG. 2 is a front view of the saddle pad;
FIG. 3 is a perspective view of the top, rear, and right side of the saddle pad;
FIG. 4 is a left side view of the saddle pad;
FIG. 5 is a top view of the saddle pad;
FIG. 6 is a bottom view of the saddle pad; and,
FIG. 7 is a rear view of the saddle pad.
The portions of the saddle pad shown in broken lines (e.g., the seam stitching, the cross-hatch quilting, and the straps) form no part of the claimed design.