Ask the Vet – Swayback in horses

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DAN: “What causes swayback,
and how do you prevent it?” DR LYDIA GRAY: Well,
there’s no answer to either of those questions. So we’re done. DAN: That’s the
end of the episode. DR LYDIA GRAY: So sway back
would be the colloquial term, and the term that the
veterinarian would use is lordosis. And lordosis means an inward
curve of the spine or an arch, versus a kyphosis is an
outward curve or a hunch, and then scoliosis is a
sideways or lateral curve. They all have names. It’s hard to tell what
she’s thinking of. There’s early onset lordosis,
like in a young horse, and then there’s the old-age
associated or late-term. DAN: Which most people
feel is common to see. DR LYDIA GRAY: As
the horse ages, the soft tissues that hold the
spine rigid begins to sink. Those tissues
become lax or loose, and the muscles in the belly
and the back sort of become less strong, and the whole
thing sort of sags over time. DAN: OK, so the
muscles in the abdomen is not strong enough to
also keep the back up, plus the back muscles are– DR LYDIA GRAY: Ligaments
and the tendons, they’re sort of
loosening, and softening, and not doing– they’re
not as structurally sound. But it’s different
in the young horse. There’s a theory that
the young horse– there’s a deformity in
the vertebrae themselves. Because if you’re 18
months or two years old, and you have not a gentle
sag like an older horse, but a pretty extreme– that looks different,
and you would suspect the bony
shapes to be different, and radiographically,
it’s been shown they are. DAN: So there’s something
more severe going on. DR LYDIA GRAY: Yes, but
interestingly enough, horses are one of
the only species that can have a significant
lordosis and not be affected. They can still have a normal,
long, healthy, productive life. DAN: But could you ride them? DR LYDIA GRAY: Yes. DAN: Interesting. DR LYDIA GRAY: Yeah. It does not seem to
affect their performance, their way of going, they
could still be a brood mare. DAN: We’ve all
seen that horse who looks a little dipped
in the back, where it’s a nice little seat
for you to sit in, but I always thought there
might be some discomfort that goes along with that. DR LYDIA GRAY: It
doesn’t appear to be, just talking about
the back issue. Now, when you put a saddle on,
then you could create an issue because if you’ve
got a back that dips, now you’ve got the potential
to create bridging, where the front of the saddle
and the back of the saddle touch, but the middle doesn’t. DAN: OK, so now you’re
hitting weird pressure points. DR LYDIA GRAY: Yeah. So now you have to be
really, really careful that your saddle fits if you’re
going to have– if you’re going to continue to ride it. A horse that ages into it or a
horse that just has it from the get go. DAN: Well, there are a
lot of saddle pads now that are designed
to kind of help with some of that
bridging for horses who do have some sway
back to kind of help that out a little bit. DR LYDIA GRAY: Yeah,
and I would probably engage in services of a
saddle fitter to make sure. A couple more things
I wanted to say was that the reason this
is not studied a lot– and so causes and
prevention and correcting– is because only about 1%
the general horse population has this, and it’s just
not enough for the money to be there to research it. About 7%, though, of American
Saddlebreds have this. DAN: I was going to say. DR LYDIA GRAY: I’m sure
you were thinking that. It can happen to any
horse, but Saddlebreds, they are now
confidently saying there is a heritable or
genetic component to it. The specific gene has
not been identified, but they’re really close. They do know that the gene is
recessive, not dominant, which means you have to have two
copies of it to show it. So the sire and the dam
must both have a copy, if you remember your
Mendelian genetics. DAN: I remember my
little Punnet square. I knew it would come
in handy one day. DR LYDIA GRAY: So it’s seen
more often in Saddlebreds, and when it comes
to the causes– for Saddlebreds, at least–
there is a genetic component. Preventing it, other
than not breeding two horses that have
it, that’s the only way you can prevent it. And then once it begins,
there’s not really anything you can do about it. DAN: Well, I was
just going to say there’s not any
sort of exercises you could do to help support
the abs and make sure the horse is engaging? DR LYDIA GRAY: Maybe for the
old age onset version of it, you could encourage
them to have that lift in the back, and the
roundness, and you do exercise that support– the abdominal
muscles, but I think you’re just prolonging
it or extending their normal lifespan. Or slowing the progression down. DAN: It’s not going to cure it. DR LYDIA GRAY: You’re
just slowing things down. Slowing the inevitable down.

 

2 Responses

  1. Tiana W

    July 10, 2019 5:37 am

    I think a horse rounding its back and collecting has a bigger impact to horses with sway back than you mentioned (watch this video) https://youtu.be/Qln5rs1ln8Q

    Reply

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