Thrush treatment and prevention is so important for happy hooves!
This is a hoof that has a deep thrush infection. If you can squeeze the back of your horse's hoof like this, they may have a bad central sulcus thrush infection. An infection this severe can cause excruciating caudal (heel) pain for your horse, causing them to land toe first. Landing toe first leads to under stimulation of the digital cushion in the back part of the hoof, which can lead to navicular pain, contraction of heels and other severe hoof/body issues.
My favorite treatment for a central sulcus thrush infection is a combination of Pete's Goo and food-grade diatomaceous earth.
Pete's Goo is a 50-50 mix of:
Triple antibiotic ointment
1% clotrimazole ointment
Mix Pete's Goo is a syringe or mix in a cup, whichever is easier for you. Squirt into the central sulcus (crevice in the middle of the frog) and then pack with food-grade DE. If possible, wrap the hooves to insure a good treatment. Apply daily (2x for severe cases) until infection is gone.
For mild thrush infections, I recommend using a 50-50 mix of apple cider vinegar and water to spray onto the bottom of the hoof, then pack the hoof with DE and wrap if possible.
For acute thrush infections or for prevention, I recommend spraying the apple cider vinegar/water mix on the bottom of the hoof.