Hoof horn disorders, causes and cures (Proceedings)
General principles of therapy for digital diseases are to eliminate the pain first and foremost and then to correct the underlying problem if possible. Hoof horn that is detached from underlying layers of hoof or corium should be removed. Around areas of exposed corium the wall or sole should be thinned to make the existing hoof capsule more flexible along the border of newly developing cornified epithelium. Bandages do not promote healing but may be used to control hemorrhage or to maintain some antibiotic or antiseptic in contact with a wound. Regardless of original intent, most bandages should be removed in a few days and the lesion left uncovered. Hoof blocks are an essential tool for managing painful conditions and their use should be routine. Non-steroidal anti-inflammatory drugs such as flunixin and ketoprofen should be considered to reduce the pain of some severe claw horn diseases and following surgery of the digit. Their use is not encouraged enough by most veterinary practitioners.
Basic tools for lame cow therapy include left and right hoof knives and small hoof nippers. Additional tools that are in wide use are long handled hoof nippers and electric angle grinders with carbide-toothed chipper wheels. There is a wide variety of restraint devices present on farms and still some farms have nothing. Practitioners should encourage every client to have a safe and efficient place or device for lameness work since every herd will have lame cows and most practitioners, at least in the United States, do not travel with a trimming chute to every call. Since most lameness occurs in the rear feet, simple devices for small herds should be made available to make rear limb lifting and examination easy.
White line abscessThe most common location is in the posterior third of the white line of the rear lateral claw. The presence of this lesion may be detected with the response to finger pressure on the bulb of the heel of the affected digit. If the abscess is near the toe tip it may be necessary to apply pressure with hoof testers to identify the location. In the fore limbs the most common site is the posterior quarter of the medial claw. Usually white line abscesses are quite obvious after a thin layer of horn has been removed. There often is dark discoloration of a portion of the white line. Sometimes the white line is fissured with manure packed into the resulting crevice which must be cleaned before the specific site of the abscess becomes visible. Relieving the pressure within the abscess provides some immediate pain relief. Abscesses near the heel may dissect between layers of sole horn to exit at the heel resulting in a transverse flap of detached horn. Much less frequently than in the horse, abscesses under the wall may erupt at the coronary band. Treatment is to remove the detached horn and trim to allow walking without pressure on the inflamed corium. Large abscesses and those at the toe tip will benefit from the use of a hoof block on the healthy digit. Bandaging is discouraged. Most cows recover uneventfully and reexamination is not necessary. Hoof blocks should be removed in about 4 weeks. Occasionally white line abscesses will extend into the soft tissue structures of the digital cushion and involve structures posterior to the distal interphalangeal joint. These conditions require surgical intervention that is described later.