Yes, abscessing in the hoof is normal. From the standpoint of healing, abscessing is usually a good sign. From the standpoint of the human and pain management, it’s a bear – to put it politely. I find that there are three different types of abscesses. One is absolutely linked to positive healing, one can be questionable, but is usually a good sign and the third is not usually associated with good healing, usually it’s related to some type of stress or trauma. The abscesses I mention here are related to founder or some type of mechanical problem with the foot. These have nothing to do with the typical ‘bad’ abscesses associated with stone bruises, punctures from nails, etc., or from ‘hot’ nails from a recent shoeing. The three types that I run across with founder cases are 1) clear, serum-like, 2) thicker, smellier puss type and 3) bloody type.
Clear abscesses – The cause of the clear abscesses can be tricky to figure out sometimes and can be tricky to determine if they are good or bad. If the coffin bone is putting undue pressure on the inner sole, irritating and / or bruising the inner sole, for instance, due to excess toe length or a longer break over, then this type probably isn’t a ‘good’ abscess. But if it’s in relation to bone re-alignment within the hoof do to proper trimming or from proper adjustment of the mechanics of the hoof, but there is no sloughing off of tissue associated with it at that time, then this type of abscess is generally good and the health of the foot is headed in the right direction.
Puss-type abscesses – The cause of the smelly puss-type abscesses is almost always good. From my experience, I have found that this type of abscess is discharging unhealthy tissue from within the hoof. They tend to be either a yellowish gray or a greenish gray color and usually have an offensive odor. They are almost always a good sign of healing. The feet can only get rid of unhealthy tissue in one of two ways, the tissue has to either grow out (as with the dead keratonized lamina) or it has to slough it off, or liquefy it, and discharge the tissue (as with much of the connective tissue deeper inside the hoof).
Bloody abcesses – The cause of the bloody abscess is usually not a good sign, but is rarely ever a horrible occurrence. If it happens to your horse, it’s not the end of the world, so don’t get too alarmed. I have found that this type of abscess generally occurs after the horse has had a day or two of being rambunctious before the feet are able to handle the added stress. This usually occurs earlier in the stages of founder recovery because the horse is feeling better, but the coffin bone has not had a chance to develop a strong, sound laminar attachment with the hoof wall. This tends to tear or rupture some of the many thousands of micro-vessels in the foot resulting in some bleeding within the foot. The blood will almost always look like good, healthy blood when it erupts with one difference, when the blood ruptures and drains, it will not continue to bleed, rather it will simply drain and the flow will stop. No continued bleeding means it was an abscess and not some vascular problem within the hoof or some other such issue.