The frog is the softest part of the hoof, even though it is made up of the same fibrous material as the rest of the external foot. It’s softer and more pliable because it contains oil glands and more moisture than the hoof horn and sole. In moist conditions, the frog might be nearly 50% water, by weight.

Being softer and more flexible (a bit like rubber), the frog functions as a shock absorber — directing the concussion outward instead of up the leg — when the foot hits the ground. The softer frog complements the relatively rigid hoof capsule, allowing the hoof to have some give (enhancing its ability to expand when weight is placed on it) to counteract the shock and concussion of traveling on hard surfaces.

When trimming the frog, occasionally the farrier encounters small pockets of whitish fluid. If he or she hasn’t run into these pockets before, the first thought might be that this is an abscess — except there’s no soreness and the fluid is not the pus you’d find in an abscess.

What Is It?

Some hoof-care professionals feel that these secretions…