Hoof Abscesses 101

What causes an abscess?

A hoof abscess occurs when bacteria and debris enter the hoof. The body’s response is to send cells and enzymes to the area, forming a purulent material, or more commonly known to horse owners as pus. As the pus accumulates, it builds up pressure under the hoof and it is this pressure that causes the lameness.

Here’s a list of the common causes:

Environmental conditions cycling between wet and dry: in very dry conditions the hoof dries out and can shrink slightly like a dried-out sponge. This can result in tiny hoof cracks and fissures in the white line that can then soften and fill with muck when the weather turns wet, allowing opportunistic bacteria to invade the hoof and cause an abscess. This is the most common cause of an abscess.

Penetrating wounds: these can occur as a result of a horse stepping on a sharp object such as a nail, sharp stone, flint or broken glass. The perforated hole that is caused as a result of this, seals over and then an abscess appears in the following few days.

Poor stable management: soiled bedding that is wet with urine contains lots of bacteria that can invade the foot and result in an abscess.

How do I know when my horse has got an abscess?

How and when you will know depends on the severity of the infection. The following clinical signs will give you a good idea: 

• Lameness: In the early stages, lameness could appear very mild, i.e. slightly unlevel; it could progress to moderate and then to acute, severe lameness. The degree of lameness varies from being subtle in the early stages to being non-weight bearing 

• Increased digital pulse: felt at the level of the fetlock, will usually be fast and the foot in question will be warmer than the opposite one 

• swelling of the pastern and/or fetlock 

• Sensitivity: to hoof testers or a soft, sensitive area around the coronary band or heel bulbs. 

What is the treatment for an abscess? 

Contact your vet immediately if you suspect an abscess, especially if your horse is acutely lame. When possible, the vet drains the abscess through the sole for two reasons:

• the crack or puncture that can lead to the abscess generally is in the sole, and it can be followed to the abscess
• this puts a hole beneath the abscess so gravity can help pull out the pus. Cleanliness is absolutely essential during and after the procedure.

After the abscess has been drained, a progressive daily improvement should be expected. Rarely are antibiotics given or appropriate except when there is risk of bone, joint or tendon involvement.

Unfortunately, not all abscesses can be opened immediately. They may take days, weeks or even months before they consolidate. In some cases, they may travel all the way up the hoof wall and rupture at the coronary band. These are the most frustrating and can sometimes be confused for another source of lameness.

Following an abscess horses have been traditionally confined to box rest until it has healed. However, there are now a great range of boots can be used for turn out. Keep one of these in your first aid kit, so that you don't have the stress of trying to buy one at the same time as dealing with the abscess itself. 

How can I prevent my horse from getting an abscess?

The best way to prevent hoof abscesses from forming is to have good, consistent farrier work because they are more likely to form when the hoof wall becomes too long and starts to separate at the white line. The vast majority of horses should be trimmed at least every six weeks and some more often.

Take home message…

Abscesses are a very common, often very painful condition that is an easily treatable cause of lameness. Getting your horse’s feet regularly trimmed will help. If you suspect an abscess, call your vet immediately for advice.