Non-weightbearing Lameness

I had a call last week on my way to a lesson from my client, asking if I could meet her at the field as her pony was very lame.

When I got there, I saw the pony standing with her front foot resting on her toe, not bearing any weight. She’d obviously been stood in that spot for a while, so I checked her leg for injuries or swelling. She has a field to herself so I could rule out a kick injury. She could’ve slipped in the field, but that’s unlikely with a front leg lameness. A twist or sprain was possible, but there was just a bit of heat from the knee down and minimal general swelling. No specific lump.

Textbooks always say to call the vet immediately if your horse has a non-weightbearing lameness, and I tend to agree, but with this mare there was no obvious injury to the leg, which made me suspect the problem was in her foot. Combined with the wet weather, my suggestion was that she had a foot abscess.

We slowly led her in, hopping along, whilst ringing her farrier to see if he could come out a check for pus. He was very busy, but told us to poultice until he came. Which was what we were going to do anyway!

We washed her legs thoroughly, prepped her bed, and applied a hot poultice. Then I left my client with instructions to poultice twice a day, check for pus, and nag her farrier until he arrived!

Pus duly came out, of which I was secretly relieved to have diagnosed correctly, and the farrier had a dig about to relieve the pressure, and release the pocket of pus.

I thought I’d already done a blog about foot abscesses, and I have. But I’ve already reblogged it so you’ll have to follow this link to read my full explanation. Perhaps I need to do a blog on poulticing next …

Keratoma

I apologise if you’re browsing my blog whilst eating dinner, or breakfast, because this post will have some gory pictures later on.

Today we’re going to talk about keratomas, which must be one of the worst ailments a horse can suffer from because of the lengthy recovery time and the difficulty in  keeping it infection free.

A keratoma is a tumour within the inner layers of the hoof wall. They are benign and therefore do not spread to other parts of the body.

Keratomas originate at the coronet band, and grow down to the toe, extending out to the white line when it reaches sole. They are usually situated at the toe, occasionally the quarter, at any height between the coronet band and sole.

No one knows what causes keratomas, but it has been suggested that chronic irritation of the internal, sensitive laminae from injury or infection could be the cause.

Due to the fact the tumour is encapsulated within a rigid structure a keratoma cannot be easily seen or felt. The first sign of a keratoma is lameness, possibly with a bulge of hoof wall at the coronet band. Depending on the rate of growth of the keratoma, the lameness can be sudden onset, progressive or intermittent. 

To diagnose a keratoma, the vet will use hoof testers to find areas of pain, check the white line for flaws or signs of separation. X-rays and MRI scans provide a definite diagnosis and allows the vet to identify how advanced it is and if there is any damage to the pedal bone. They can also take a biopsy too for confirmation.

The next step is to remove the keratoma. This requires surgery, when the hoof wall is cut out and removed over the keratoma so that the tumour can be taken out completely. Afterwards the vet will pack the wound with antiseptic gauze, and fit a hospital plate to the shoe (I actually have one of these!) to help protect the foot. A bandage around the foot helps to keep the wound clean and dirt-free. The patient then needs a course of antibiotics.


Post surgery, the horse has to stay on box rest, in as clean a environment as possible, with the wound being checked and re-dressed every couple of days until a hard layer of horn has formed. Once the hospital plate and bandage are defunct, then the horse will need remedial shoes to best encourage the hoof to grow, and to stabilise and support the weakened area. The foot needs to be kept clean and dry until the hoof has completely healed, which takes many months when you consider that it takes twelve months for hoof to grow from the coroner band to the sole, the recovery rate for a keratoma is slow to say the least! The prognosis is usually good, and providing the keratoma is completely removed, the risk of reoccurrence is very slim. You just need a lot of patience, a good farrier, and a horse who likes his stable!

 

Hoof Wall Separation Disease

I went for a hack last week with a friend and we were chatting about mutually known ponies, as you do. She had recently passed up on buying a Connemara for her daughter. The pony is talented, and has a good level of education, but unfortunately he suffers from Hoof Wall Separation Disease, previously known as Hoof Wall Separation Syndrome.

I had never heard of it, but it is a genetic problem for Connemaras. Basically, it is caused by both parents carrying a recessive gene, meaning that it is quite difficult to trace as carriers have sound feet. 

Ponies with HWSD have hoof walls that crack and crumble very easily. All four feet are affected, and symptoms can be seen as early as 2-3 weeks of age, but it will always develop within the first year of life. Pieces of hoof crack, chip and peel off, often involving the whole of the dorsal wall. As the hoof grows down to become weight bearing it will immediately deteriorate, leaving the horse walking on the soles of his feet, with no dorsal support.

Some people confuse HWSD with White Line Disease, but a horse with HWSD will not respond to treatment for white line disease or fungal infections.

Some horses can display a milder version of the disease which can be managed to a degree, but most horses suffering from HWSD are euthanised. The condition tends to worsen with age and the foal will develop severe infections as well as being in severe discomfort and pain.  

Horses with the milder version of HWSD can be managed by remedial shoes, types of hoof care, restricting turnout or exercise so that the hooves are not exposed to wet-dry conditions as changes in response to environmental factors can worsen the disease.

There is now a test for HWSD, and a lot of breeders with Connemaras and part bred Connemaras are having their breeding stock tested so that two carriers are not bred together. Carriers will have normal feet, so there is no way to observe the presence of one recessive gene.

People are calling for the HWSD test to be a legal requirement of Connemara breeders, but it’s just as important to educate potential buyers of the disease so that they request a horse be tested for it during a vetting. If the market stops buying affected horses then breeders will take note and stop breeding from carriers of HWSD.

Grass Cracks or Sand Cracks?

I noticed a barefoot horse I was bringing in had a couple of cracks in his hoof last week, and with the ground conditions changing so rapidly it’s not really surprising.

Cracks in the wall of the hoof can occur for numerous reasons, but good care helps eliminate the problem.

There are two main types of cracks; sand cracks and grass cracks. I learnt that an easy way to tell them apart is that a grass crack grows upwards, like grass growing up from the soil; and a sand crack grows downwards, like sand running down an hourglass.

Grass cracks tend to be superficial; thin and not penetrating very deep within the hoof wall. They occur when the ground conditions change from very wet to dry (such as in the last fortnight), due to poor nutrition as hoof growth is inhibited, and lack of exercise as exercise increases blood flow to the hoof. Horses aren’t usually lame due to a grass crack, but they should be treated by the farrier when he next comes. Applying hoof oil to a crack only locks moisture and bacteria in, so whilst hoof dressings have their purposes when used on unbroken feet, they shouldn’t be used on open areas. If an infection gets into the crack it can be very difficult to treat. The farrier may adjust his shoeing or trimming to support the crack, and if it is large and he or the vet are called as the horse is unlevel then they can repair the crack by either clipping it together with small pieces of metal, or filling it with a resin or polymer.

Sand cracks are caused for similar reasons to grass cracks; however, they originate from the coronary band and extend downward. The danger I was taught with sand cracks is that a piece of dirt can get lodged into the crack and cannot escape, so it becomes infected. In a grass crack, gravity with pull the intruder down and out, but the solid bottom of the sand crack traps it. Sand cracks can be treated by burning a horizontal groove at the base of the crack, to prevent it from growing deeper.

QuarterCrack001

So whilst most cracks aren`t anything to worry about, it does imply that the feet are becoming brittle and in need of a farriers attention so that they are balanced and there are no stressed areas, which are predisposed to cracking. A hoof supplement can be fed to help strengthen the hooves in the long run, and your farrier may also recommend a hoof dressing; I use a tar-based dressing that comes highly recommended.

 

Foot Abscesses

Foot abscesses are a very common ailment for horses and can be a recurring nightmare for some owners.

Also known as pus in the foot, a horse can be mildly lame or not bear weight on the injured leg.

A foot abscess is caused when a sharp object, for example a stone, penetrates the sole of the hoof and bacteria gets in, and the superficial layers close over, and a localised infection develops. The pressure builds in the foot, causing pain as it touches the nerves and causes the lameness. The foot also becomes inflamed, with a bounding pulse and heat in the hoof.

If you suspect an abscess in your horse then either the farrier or vet can test for pressure points in the hoof using hoof testers. When a sensitive area is pinched the horse will flinch, indicating pain. If a horse has shoes they may need to be removed to access the abscess. That area can then be parred out to release the pressure. When the surface of the abscess is pricked pus usually bursts out, causing a lot of excitement amongst the farriers. I remember our farriers arguing over who got to “hunt the pus”.

Once the dead tissue has been removed the foot needs to be poulticed to keep the abscess clean, allow it to drain and heal. Usually a wet poultice is applied for the first few days before a dry poultice to help dry up the foot before the shoe is replaced. The horse needs to be kept on box rest, and the foot kept as dry as possible, so the bed should be meticulously clean. The poultice needs changing at least once a day. If an abscess is difficult to treat and a prolonged wet poultice is required the sole of the hoof can become soft and thus prone to reinfection, so a hoof hardener can be applied with the dry poultice to strengthen the tissues.

Antibiotics are rarely used in treating abscesses but sometimes a painkiller is used for the first couple of days to keep the horse comfortable. Pus in the foot carries a high risk of tetanus, so it is important horses are vaccinated against it.

Horses with flat feet or soft soles can be prone to foot abscesses, or those with poor foot care and living in wet conditions.