Tuesday, December 10, 2013

What's the deal with hoof contraction?

A word that gets thrown around a lot when it comes to hooves is contraction, but I think a lot of people new to hoofcare don't really know what that means. I'm going to try to help you out.

con·trac·tion


: the act or process of making something smaller or of becoming smaller 

 Normally when someone says that a hoof has become contracted they mean that the back of the hoof, the heels, have shrunk/become pinched like in these feet (I snagged these pictures off the web):







What's wrong with that? There are structures inside the hoof; like the coffin bone, navicular bone, live frog, digital cushion, and lateral cartilages that are all negatively impacted by hoof contraction. There's only so much room inside the hoof, and when that space gets smaller- through contraction- they stop functioning correctly. The lateral cartilages lose their efficiency at pumping blood, the digital cushion loses its shock absorbing function, the coffin bone itself can even be remodeled due to the pressure. All this measures up to a horse with impaired movement at best and dead lame at worst.

What causes contraction? Simple: The horse not landing on the back of the foot. Without the weight of the horse pressing on the heels, they don't expand.

 How can you tell that a hoof is contracted? Take a look at the hooves above, they all have a few things in common. For one, they all have long toes. Yes, even the second one down, it's not as long as the others but it'll get there. Toe first landings = long toes as the constant pressure will stretch the lamina and sole. Second, look at the frogs, they are all narrow little triangles with ugly looking trenches in the central sulcus collecting thrush. Third, look at the bars, they are all very long. Lastly, look at the heel bulbs and see how they look like cleavage squeezed tight in a corset.

Here's a hoof that isn't contracted, can you see the difference?

The trim isn't perfect, but you get the picture
Most of us know that horses should be landing on their heels because that's where the shock absorbers of the hoof are. So what would cause a horse to land on their toes instead? It's normally because of pain in the heels, you just have to figure out where the pain is coming from.

Let's go back to the thrush issue real quick: Thrush and contraction go hand in hand (or hoof in hoof). As the hoof contracts the frog folds up like an accordion, creating that deep crevice you see in these photos. Thrush just loves deep, dark crevices like that. Some people think (and I thought this myself once) that the pain from thrush can cause contraction. What I've learned recently points to the contraction happening first, making a nice, comfy home for the thrush to move into later.

So can anyone guess what I'd say caused the contraction in the above hooves?

11 comments:

  1. I don't have a clur but I'll be waiting for the answer.

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  2. I'm going to throw out a guess with what I have seen cause hoof contraction in my horse in the past. . .no turn out or not enough turn out. Now that she is out 18-24 hours a day, her hooves look much better to me. Possibly turn out on soft ground or not enough variation of the ground, too?
    I am interested to see the answer!

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    1. Movement is so, so important. Good call on that one!

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  3. Because I am now part of the barefoot cult (hehe), and because I've seen it first hand with my own horse, I'm blaming the majority of cases on shoes. Not just shoes, though... a poor trim before the shoes go on, and also shoes being left on too long between trims.

    I'm not sure I've ever heard of contracted heels on a horse that has never been shod, although now that I've said that, I'm sure someone will correct me. :)

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    1. My gelding has never had shoes on and his feet are contracted.

      It's not about the shoes (some farriers can shoe a horse without contraction, they are magicians) - like you said, it's about the trim and the length between trims. A poor trim done infrequently doesn't do the horse much good.

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  4. The last time I saw Dee's feet she had very long heels and bars- do they still look like that?

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  5. Long bars

    Because I know how you love trimming them!

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    Replies
    1. You get me, you really get me :)

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    2. I think Val does get you. :-) I would have said shoes, but I think bars have it.

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