All you need to know about White Line Disease, but didn't Know what to ask.
Nail Hole Disinfectant is a new product from Keratex. But why should you want to disinfect the nail holes?
Over the last 5 or 6 years there has been a lot of discussion in farriery and veterinary circles about what many thought was a newly diagnosed hoof condition. What brought this about was an increased incidence of infection to the white line which resulted in cavities and eventual lameness if left untreated. This condition is widely called 'White Line Disease', but is now more correctly referred to as Onychomycosis (fungal infection of the white line or stratum medium) or Onycholysis (separation of the horn from the laminae).
Early on, when great effort was made to identify the causes of white line disease, there were many sceptics who proclaimed that this was not a disease, but was merely an extension of hoof separation caused by poor shoeing. (Separation cause by inappropriate shoeing will resolve after the hoof has been shod correctly several times). This argument gained credence because no-one had been able to make a culture of any relevant organism from biopsy material taken from affected hooves.
However, work done by Burney Chapman in America revealed two organisms were present in infected hooves. These were identified as the fungi Pseudallescheria boydii and Scopulariopsis. These organisms are commonly found in soil and once it was known what to look for they have been identified in biopsy samples worldwide.
Surprisingly they are the same organisms which affect humans with abnormal immune systems, as found in AIDS sufferers and long term drug abusers. These organisms are unlikely to affect healthy people. Because of this it is thought that prolonged use of certain drugs in the equine may predispose an animal to white line disease. What is known is that white line disease may manifest in just one horse in a large yard, while all others are unaffected. Equally, it seems unlikely that the disease is transmitted by farriers tools for the same reason.
Currently there are still no definite indicators as to why some horses are affected and others are not, but what is known is that the disease is far more widespread that previously considered, due mainly to new information and the awareness of vets. and farriers to the symptoms.
What to look for
In the early acute stages white line disease is most often spotted by the farrier, if he knows what to look for, when the shoes are removed and he has dressed the bearing surface of the hoof.
Normal healthy white line is a creamy white colour and may occasionally be stained dark brown from metal oxide in the proximity of a close nail. Do not worry about this.
If there appears to be a grey stain, which may only be 1-2cms long and covering the width of the white line, this is a typical early symptom which requires investigation. Usually at this stage the infection may only be 1-1.5cms in depth and can easily be removed by the farrier.
Use Keratex Nail Hole Disinfectant to flush the area once all discoloured tissue has been removed. The affected tissue may have a bad smell, similar to that associated with thrush. Insert cotton wool or felt into the cavity and soak with Keratex Nail Hole Disinfectant twice a day for at least two weeks to be sure all the infection has been eradicated. After two weeks check the cavity for further signs of discolouration and if none are present fill the cavity with Keratex Hoof Putty, to prevent the ingress of muck and dirt.
Having diagnosed a horse as prone to white line disease all hooves should thereafter be regularly checked for early symptoms and attended to as indicated.
In chronic cases the organisms will have destroyed large areas of white line, which may extend high up the inside of the hoofwall. This may cause lameness through muck and dirt impacting into the cavity, causing pressure on the internal structures of the hoof. In advanced cases such as this it will be necessary for the farrier or vet. to perform a hoof resection by removing the horn overlying the site of the infection. (White line disease can often be the cause of horn breaking away around and below clenches and old nail holes and should be investigated accordingly.)
Horn will be removed to expose at least 5mm of sound white line in front of the advancing infection. All the necrotic tissue must be removed, including 2/3 mm of apparently sound tissue in front of the infection. The dead tissue will have a cheesy appearance, will be smelly, and may be grey or brown/grey in colour.
Once all necrotic and infected tissue has been removed soak with a benzoyl peroxide preparation and pack the area with cotton wool or felt. Keep this packing clean and regularly reapply the benzoyl peroxide preparation.
As the organisms responsible for white line disease are anaerobic (capable of living in an oxygen free environment) rebuilding resected hooves with hoof filler can be contraindicated as, apart from preventing inspection, the exclusion of air can allow any remaining infection to flare up and progress to other previously uninfected areas.
Although certain horses are susceptible to white line disease and others are not it is a widely held opinion that those animals that become infected will have a poor prognosis, and reinfection will occur unless a regular maintenance programme is adopted.
Resected hooves will require specialist shoeing to improve weight bearing over the remaining hoof wall. Heart bar shoes are most commonly used as these provide support for both the hoof wall and frog.
It is essential to maintain good clean bedding, preferably straw, and to avoid 'deep litter' or absorbent bedding materials.
Horses prone to white line disease require vigilant husbandry and specific regimes to prevent reinfection.
The oganisms responsible for white line disease are freely available in soil, and throughout the equine environment, and most probably enter the hoof tissue in water absorbed into the hoof and entering through nail holes and up the tubules of exposed horn at the base of the hoof wall.
Since information about white line disease, or onychomycosis, has become available and the symptoms more readily recognised, the real incidence of this condition is becoming quite alarming and is increasing on a worldwide basis. Maybe it is due to the increased usage of new and different drugs, maybe it is due to other quite unrelated factors, but at the moment nobody seems to have the final answer.
Because so little is known about white line disease, and why some horses are infected and others are not, it must be assumed to be a randomly occurring condition that can attack any horse at any time. This is why vets and farriers have been looking for ways of preventing infection taking a hold in the first place, and why Keratex have developed Nail Hole Disinfectant.
Keratex Nail Hole Disinfectant uses a totally inert state of the art penetrating fluid to carry special disinfecting agents deep into the tissue surrounding nail holes. Because it is so highly penetrating, Keratex Nail Hole Disinfectant quickly spreads through the healthy tissue underlying the hoof wall and prevents the organisms causing white line disease from developing and spreading.
Keratex Nail Hole Disinfectant can be used as a preventative on horses which have remained uninfected, or as a maintenance in horses with a history of infection.
Application is simplicity itself. Just draw up some Keratex Nail Hole Disinfectant into the special pipette provided and then slowly squirt it down each old nail hole in turn. From then on it works for you and only needs applying once a week.
Vets and farriers all agree that prevention of white line disease is better than cure.
The above information is intended as a guide to identifying and stabilising white line disease. The surgical and farriery procedures mentioned must only be carried out by suitably qualified farriers and veterinary surgeons.