The photo above is of a healthy frog.
Most often overlooked is the health of the frog on the horse's hoof. Frog infections are easily missed by owners and vets. A horse can pass a vet check and have a serious deep frog infection. I have seen farrier's overlook bad frog infections. The horse is usually labeled as having navicular or some other cause of lameness. In most cases, none of these horses have navicular, they have a deep infection of the central sulcus. This type of infection presents itself with closed bulbs, contracted heels, a slit for the central sulcus or decayed frog in place of the sulcus, and/or curved bars which pinch off the frog corium preventing proper circulation and function of the frog.
For healing to take place, the horse must be barefoot and trimmed in a natural balanced way. Disinfectants and anti-fungal ointments must be applied on a regular basis and the foot must be kept clean and dry. The hoof needs to be scrubbed clean with an anti-fungal shampoo and then treated on a daily basis. The best treatments I have used that work are Thrush Magic, Well Horse Thrush Off, No Thrush and my own mixture of oregano oil and grapefruit seed extract equal parts. These must be injected into the central sulcus. There are many products on the market that work well such as White Lightning. Finding the right one that works for your horse and it's environment is important.
The horse's environment must be clean and dry. You will not be able to clear the infection if the horse is constantly in an environment that is damp, and wet and is the breeding ground for yeast infections and fungal infections. Sanitize rubber mats and other areas in which your horse stands. If you board your horse, there are many different horses that may use the same cross tie, wash rack etc. These areas are perfect breeding grounds for these infections. You don't know if the horse before you has an infection. If they do, it can easily be transferred to your horse in these areas. These areas can be sanitized using bleach and then hosed off.
The photo at the top of the page is the left front present day. The photo below is the left front a year ago with the infection. Under that one is the right front with infection and under that is the right front one year later. This horse passed a thorough vet check with this serious infection. Take note of how the bulbs in the photo above are opened and spread and compare that to the one below, where the central sulcus is a slit and the bulbs have folded in closing off the area, creating a perfect breeding ground. The frog in the infected foot is compressed and narrow, and the frog in the healthy foot is spread and plump. These photos present an obvious difference.
Please check your horses frogs. If you see slits where there should be a central sulcus you have an infection. If your horse never seems quite right, something off but you can't pinpoint it or are a little tenderfooted, check the frog. It is essential to their soundness.