Q: What’s the best way to manage “sinkers?”

A: In the majority of cases, euthanizing the horse is probably the right choice for practical and humane reasons. "Sinker" means there has been sufficient damage to the attachments of the coffin bone that the coffin bone - and thus the skeleton- has been displaced within the hoof capsule. That's opposed to the coffin bone simply rotating at the toe. This means there has been massive destruction. It is the most severe form of laminitis damage, and the owner, farrier and veterinarian should communicate to determine whether they want to continue treating the horse.

It's very unlikely that a horse with this degree of damage will go back to work or athletics. If the decision is made to try to salvage the animal for breeding purposes or some other reason, they have to consider that no single method has proven to be better or more successful than any other. Each of the horses with this problem is different in weight, size, shape of the foot, distance of the coffin bone from the bottom of the foot, availability of expertise, cost, number of feet involved and other factors.

Sinker cases can be very complicated and difficult to manage. The shape and quality of the foot or feet even before the problem may be limiting factors.

What you attempt to do with the bottom of the foot, and with the surface the horse lives on, is provide protection with the hope that the sinking stabilizes. That often is a function of how much damage was done when the horse developed laminitis.

Some of the methods that have been used require more than the efforts of a farrier. In some cases, a vet will put pins through the cannon bone and secure them to a brace and a cast. When the brace comes down to the floor, the foot isn't hitting the ground. In some instances, vets have amputated the foot and applied a prosthetic device. That's been met with varying degrees of success. Success is possible, but the odds are not favorable.

William Moyer

William Moyer

In a case I was involved with long ago, all four hooves sloughed. I removed the hoof wall, sole and frog from all four feet on one stallion. I put him in a sling and placed him in a horse recovery pool for several months. He regrew normal feet. But when we used that same technique on other horses, the feet contracted and thus was of no benefit.

You want to be sure that all the people involved are willing to decide on humane destruction when it's necessary for the sake of the horse. Sometimes we're called on to save the poor animal for the benefit of the owner, not for the sake of the horse.

Even if the treatment goes reasonably well and the horse survives, that horse will always be at risk. Even if they can walk around or carry a foal, they still have abnormal feet and are highly likely to develop recurring foot problems.

It is essential for everyone involved to understand the facts of the situation before attempting chosen techniques. If I'm in charge of such a case, I want to know that I will have the owner's backing when I see that enough is enough. When I can no longer control the pain, it's time to put the horse out of his or her misery.

—William Moyer, DVM Texas A&M University

A: I've heard it said that 95% of the horses that sink don't make it. The large majority of the horses are going to die because they have dead feet. When we realize that they have dead feet, and that their coffin bone is sinking because they have no live attachments within the hoof, probably the best way to manage them is to euthanize them.

Glenn Anderson

Glenn Anderson

Some owners don't like that idea. They'll spend a lot of money on treatments while the horse suffers, then they lose him anyway. But I think the best service we can provide is to not put the horse through all that misery.

I don't know if there is a traditional approach to treating a sinker. It seems that wherever you try to support them, the horses don't like it. It doesn't seem to offer them any relief. Other people have done things that I find interesting and that bear looking into. For example, transfixation, which uses pins and casts to unload the foot totally. Theoretically, that has merit.

We don't see a lot of sinkers around here anymore. I don't know why we don't, but we just don't see as many severely laminitic horses as we used to. Maybe people have gotten a little smarter. It might be that the nature of our practice has changed, or maybe other people are still seeing a lot of them, but I don't even hear people talking about them as much as they used to. That's a good thing.

—Glenn "Andy" Anderson, DVM Broken Arrow, Okla.