White Line Disease: What is it and why does my horse have it?

Bev Luman

Molly WLD 002
White Line Disease goes by many names: Stall Rot, Seedy Toe, Wall Thrush, Hollow Foot, and Yeast Infection. Technically, WLD is not a disease, but rather a condition caused by one or more fungi acting alone or in combination with bacteria that infiltrate, feed upon and destroy the keratin tissue of the hoof wall. For those of us who haven’t had any hoof anatomy classes, imagine the fungus that gets under your nails and causes them to turn loose of the nail bed.

The anaerobic microorganisms responsible for WLD thrive in a moist, dark, oxygen-free environment. This causes separation of the hoof wall from the sensitive inner sole. It usually enters through a fissure or crack and starts very small. Nail holes on shod horses are a favorite place to invade. Hooves that have been neglected and allowed to over grow and crack are an inviting place for WLD to start. Caught early, WLD is easily managed. Left unchecked, it can have a crippling and debilitating affect on the infected hoof, or hooves.

If you’ve had horses for very long at all, then you’ve probably had the White Line discussion with your hoof care practitioner and dreaded the next part of the conversation where you assess how bad it is and what the best course of action will be. The bad news is that it doesn’t matter if your horse is shod or barefoot, WLD can get in the hoof. The good news though is that horses that are regularly maintained on routine schedules are more apt to catch WLD in the early stages, where it is more easily treated. Unshod horses, those under Natural Hoof Care, are easier to keep clean and dry. Shoes tend to hold in wet dirt and manure, providing a breeding ground for the bacteria and fungi.

James Luman, a Natural Hoof Care Practitioner states that a WLD diagnosis means action must be taken by the owner. “I’m only here every 6 weeks or so. If an owner doesn’t get after this stuff (WLD), and I mean get aggressive every day, we’ll lose even more of the hoof by the next trim.” The affected hoof wall must be picked out and cleaned of all the chalky debris. If caught early horse owners can pick and clean the hoof and apply various anti-fungals with good success. Care needs to be taken to keep the hoof as dry as possible. If it has spread sufficiently, more aggressive measures need to be taken. In severe cases the hoof wall must be re-sectioned to allow for sufficient cleaning and drying.

James states that while there is no empirical evidence to suggest that sweet feeds cause WLD, there is sufficient reason to remove it from any horse’s diet, especially horses with any type of hoof concerns such as founder or WLD. His experience with horses who gorged on persimmons 2 years ago and their subsequent WLD outbreaks soon after, reinforced the opinion that there is a definite correlation between sugar overloads and fungal flare ups in hooves. Rich spring grasses, sweet feeds, and persimmon or pear gorging can all be causes of sugar loading.

James relates the case of Molly, a horse who came to be under his care in April. Her owner stated that initially, Molly’s hoof had approximately a 2 centimeter start of WLD. She had been shod and was being stalled at a trainer’s. Her owner battled the ever growing problem for over a year. Each time she was re-shod, more of her hoof had to be cut away. As more hoof wall was cut away (due to the increasing damage done by WLD) and shoes became increasingly difficult to nail, an epoxy resin was used to fill in her hoof. This essentially sealed in the bacteria and fungus, giving them the perfect environment for growth and destruction. Knowing that the current line of treatment wasn’t working, her owners contacted James.

James and his team at Arkansas Natural Hoof Care went to work. The first course of action was to pull the shoes and remove all the resin. Then the hoof wall was trimmed back and cleaned out until all the affected area was removed. Molly was placed on free choice hay and was also given a no-sugar, no molasses pelleted feed and hoof supplements high in Zinc and Copper. Her hoof was cleaned twice daily and a DMSO / Epsom Salt mixture suggested by Dr. Mike Pallone was applied. By September Molly’s hoof had almost re-grown to the ground. The founder that usually accompanies severe WLD has caused the whiteline to be stretched, but with regular trims and continued care, Molly is expected to make a full recovery.

Equine specialist, Dr. Mike Pallone, states that the super wet conditions a couple of years ago caused WLD to run rampant over about a 5 state area. Veterinarians and hoof care specialist alike were battling it. Add those wet conditions to any other factor such as unsanitary stalls, sweet feeds and LOFS syndrome (Lack of Farrier Service) and you’ve got perfect conditions for WLD to set in. Dr. Pallone adds that if you suspect your horse may have WLD, you need to get on top of it. WLD isn’t something you want to mess around with.

The best defenses against WLD are, of course, routine hoof care, dry, clean living conditions and a good diet with forage first. If you suspect that your horse may have WLD, consult your veterinarian and hoof care practitioner immediately.