Vet Vibes: Hoof health in the wet

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VET VIBES

Hoof health in the wet

Wet, muddy paddocks can spell trouble for horses’ hooves. Veterinarian DR. DOUG ENGLISH discusses some of the most frequently occurring issues.

Squelching through waterlogged paddocks is no one’s idea of fun – and it certainly isn’t conducive to the health of your horse’s hooves. Best avoided if possible, wet weather woes include greasy heal, thrush, seedy toe and abscesses.

Abscesses

These commonly occur in wet conditions when the hoof becomes soft and a crack develops, or when the horse gets a stone bruise and bacteria get in and cause infection. This can result in severe lameness, and often the owner thinks the horse has a broken leg because the animal can go from sound to non-weight bearing toe pointing in about a half day.

Treatment: The abscess needs to be picked out and drained, then flushed and packed with a drawing ointment such as venous turpentine, magnoplasm, magnoplasm mixed with honey, or ichthammol. Often difficult to pinpoint the exact spot, an abscess can be encouraged to ‘mature’ by soaking in a bucket of warm to hot water and applying a poultice. Sometimes it will break out over the top of the hoof at the coronary band. While poulticing helps, you should also ask your vet for antibiotics.

Abscesses are sometimes associated with a close nail in the shoe. Hoof testers are often useful in identifying the offending nail and I always remove the shoe when presented with a potential abscess. A nail puller tool is very handy for this, but don’t forget to file off the clinch holding the nail before pulling.

Greasy heel

Greasy Heel is another disease associated with wet conditions and horses with a long feather and white skin are particularly susceptible. The ailment starts as an infection of Dermatophilus congolensis, an organism classified in an entirely separate biological class because it is neither a fungus nor a bacteria.

Greasy heal presents as crusty scabs that are difficult to remove, and a secondary bacterial infection can occur resulting in a fluid-filled swelling of the pasterns. The severity of this condition varies considerably.

Treatment: Mix 1.5 to 2 tablespoons of copper sulphate with 750mls vinegar and 250mls of water, and apply either as hoof soak or spray. Antibiotic injections may also be necessary. Removing the scabs by hand can be painful, but applying coconut oil, almond oil, raw honey, lanoline, albarol oil, or baby oil will help soften them, making them easier to remove. Scabs protect the organism, so add tea tree oil to the base oil (1 part per 100mls of oil) to kill the organism. Leave the oil on for an hour or so before washing off.

Thrush

Thrush is a bacterial infection of the frog with presents as black, sometimes bloody fluid with a foul odour. In severe cases, the bacteria can reach the dermis, the sensitive tissue beneath the frog, causing pain and lameness.

Severe cases of thrush need to be differentiated from canker, a disease in which abnormal frog tissue increases quite rapidly. In comparison, thrush is a degenerative disease in which the horn of the frog deteriorates. expansion joint and supports circulation by pumping blood back up the leg as the horse walks, while at the same time expelling accumulated debris such as manure and mud from the crevices on either side. I disagree with over-paring a normal frog to make it neater – and smaller! Healthy feet in their correct environment don’t succumb to thrush.

Thrush infectious agents are nonspecific, but can include organisms like the anerobes Bacteroides and Fusobacterium which are common in soil.

Treatment: Pare off dead tissue before applying topical plus systemic antibiotics if needed. Either spray or soak the foot with a solution of 1.5 to 2 tablespoons of copper sulphate, 750mls vinegar, and 250mls of water.

Clean the hoof daily and brush with a stiff brush, followed by the copper sulphate spray or any of the dozens of proprietary hoof medications. In my opinion, good farriery is key.

Canker

Although similar to thrush, canker is more serious because it causes deformities in the hoof horn tissue, particularly the frog. It is also more destructive and progressive. The cause is unknown but,

ABOVE: Abscesses will sometimes break out over the top of the hoof at the coronary band. LEFT: Waterlogged paddocks are not conducive to the health of your horse’s hooves.

ABOVE: Greasy heal presents as crusty scabs that are difficult to remove.

like thrush, was originally thought to be associated with wet and muddy stables. There are some studies suggesting that the presence of bovine papilloma virus in canker-affected horses is not coincidental, but indicative of an active contribution to hoof canker disease. Like equine sarcoid disease, canker is a therapy-resistant disorder characterised by a thickening and discolouration of the tissue, and a marked tendency to recur. There is one hypothesis that canker, essentially an inflammation of the feet and other horny structures, may be caused by an autoimmune reaction and this would tie in with papilloma virus. Luckily, it is not common.

While bacterial infection is an inconsistent finding with hoof canker, it can occur as a secondary infection when the barrier function of the foot is impaired. Treatment: Canker is not something that can be treated at home. It’s justifies referral to a specialist veterinary hospital, and even then, the possibility of failure should be anticipated.

Keratoma

Although uncommon, keratoma is a tumour of the keratin-producing epidermal cells of the inner hoof wall. It is a benign, keratin-containing soft tissue mass that develops between the hoof wall and distal phalanx. The tumour appears as pearls of cornified tissue all over the hoof, but most commonly near the coronary band.

Clinical signs usually consist of slowly progressive lameness due to the underlying tissue mass pressuring the sensitive laminae.

Treatment: Keratoma requires surgical removal.

WLD and Seedy Toe

White line disease (WLD) frustrates veterinarians and farriers because of the diversity in terms of its cause, diagnosis and treatment. WLD is a keratinolytic process that originates on the solar surface of the hoof (the bearing edge, bars, sole and frog) which causes progressive separation of the hoof wall’s inner zone resulting in lameness. Seedy toe can be considered to be a less serious form of WLD.

The hoof wall consists of three layers:

ƒ the stratum externum (thin outer layer) ƒ the stratum medium (the largest and most dense middle layer)

ƒ the stratum internum (the nonpigmented inner layer which contains the white line and is responsible for attaching to the hoof wall to the bone).

One or all hooves can be affected, regardless of age, sex, or breed, both barefoot and shod. Many horses have hoof separation but do not develop WLD. If left unattended debris accumulates and becomes packed, resulting in mechanical separation.

Treatment: Bacteria and fungi can potentially colonise the area, which then needs to be cut out down to solid horn and filled with a medicated hoof putty, or a paste that can be made up with the likes of Stockholm tar, venous turpentine and copper sulphate. Proper support for the damaged hoof and glue on shoes are an option. Topical disinfectants are of no use without resection of the hoof wall.

Neoplasia

Various neoplastic diseases can occur in horses’ feet, and each is a story in itself. The list includes keratoma (as described above), sarcoid (which grows in infected wounds), osteosarcoma in the bone, squamous cell carcinoma, soft tissue sarcoma, melanoma, haemangioma, and vascular hamartoma. Tumours on the equine foot are rare, and unfortunately, apart from sarcoid and keratoma, have a poor prognosis.