Genes

Last summer, some scientists published a paper about a “gait-keeper” gene in horses (see http://blogs.discovermagazine.com/notrocketscience/2012/08/29/one-g...). A mutation in this gene appears to be responsible for the “extra” gaits in “gaited” horses (rack, foxtrot, running walk, etc.). The unmutated gene is evidently responsible for coordinating the movements of the limbs. Horses with the mutated gene have to learn to coordinate their legs, rather than having it come naturally. Because moving is learned in these horses, they move in different ways from the usual walk, trot, and canter.

I found this news very interesting because I believe my current pet horse has this mutation. She has always been very uncoordinated, which I put down to the fact that she spent her first three years in a 12x12 pen. However, the fact that she’s remained uncoordinated, even after all the work I’ve put into her, made me wonder why she hasn’t improved more than she has. Now, I think I know. If a horse with the mutated gene has to learn how to coordinate its legs, it isn’t going to learn much in a 12x12 pen, so her learning didn’t really start until I bought her as a three-year-old.

I think she probably only has one mutated gene, rather than two, because she does do the walk, trot, and canter, rather than “gaiting.” However, her trot can be very arrhythmic and uncoordinated. Early on, I recognized that, if I wanted to teach her to “gait”, I could --- but all I wanted was a coordinated trot. To this day, however, she loses her coordination very easily. If we’re going downhill, or on uneven ground, or if something distracts her, her trot immediately becomes arrhythmic. I can usually get her to be rhythmic again by posting or rhythmically bumping the bit or doing something else to give her a rhythm to match, but it’s still amazingly easy for her to lose that rhythm. She’s pretty consistent on a surface where she can hear the rhythm of her trot, but if we get into grass or something else where she can’t hear the rhythm, she tends to lose it. At least now, I have a theory as to why!

My first work with her was on the ground in a round pen. She learned “walk”, “trot”, and “whoa”, and then we progressed to cantering. To my surprise (and horror), when I told her to whoa, she stopped --- and did about a triple somersault. As best I could tell, she didn’t realize that she needed to stop with her back legs under her, so she just stopped, and her momentum created a spectacular fall. Luckily, she emerged unhurt, and the episode turned into an effective learning experience. She now stops with her hind end WELL underneath her.

However, the falling problem continues to this day. Tori falls relatively frequently, and she does so in an entirely unpredictable way. Most horses fall because they have tripped, so the rider has some warning of what is happening --- albeit a brief one. However, Tori just falls. She doesn’t trip --- she just goes from upright to on the ground with absolutely no warning. The first time it happened while I was riding her, we were cantering, and my only warning was that the up part of the up-and-down head bob didn’t come. By the time I realized her head was still going down when it should have been coming up, she was in the midst of another spectacular somersault. At the time, I thought maybe she’d stepped on a rock and picked up her foot without realizing that having NO front feet on the ground would cause her to fall. Now, I wonder if she just lost her coordination and didn’t get her foot down when she should have.

Most of her falls have been while cantering, but she once managed to fall essentially from a standstill. We were working in a dressage ring and had stopped at the letter E. When I asked her to continue at a walk, she promptly fell onto her side. As she lay there in full lateral recumbency, with me still in the saddle (with one leg underneath her), all I could do was wonder how a horse can manage to fall down from a standstill. Again, I think now that she just lost coordination and when she stepped forward, she didn’t get her foot down when she should have.

I have always felt that her lack of coordination is a product of her spending the first three years of her life in that 12x12 pen, but I’ve also wondered why she hasn’t improved more than she has after all the work I’ve done with her. It made sense that having her movement limited during her formative years would affect her later ability to coordinate, but it also seemed that remedial work should have restored more of that ability than it actually did. Why didn’t a horse’s natural ability to coordinate kick in to a greater extent once she DID get to move around naturally?

Knowing about the gait-keeper gene helps explain her continuing problems. If, unlike other horses, she had to learn to coordinate her legs, rather than having such coordination come naturally, and if she was unable to learn to coordinate until she was a three-year-old, it’s not as surprising that the delayed learning has had a significant effect. There was no natural coordination ability to fall back on, so it’s all been learning for her, and learning is limited in its ability to remedy a natural lack of coordination, especially when such learning occurs later in life.

I could be entirely wrong, of course, in my belief that my horse has a gait-keeper gene mutation that explains her lack of coordination, but if she does, it certainly explains a lot of things I’ve wondered about since I first got her. It’s nice to have such an explanation when I get frustrated because something as simple as a few steps off the trail causes her feet to go haywire and completely lose any rhythm at all in her trot. It’s probably frustrating for her, too!

If nothing else, it’s been fun to speculate about whether such a mutation accounts for my horse’s problems. It’s always nice when something comes along that seems to make all the pieces of a puzzle neatly fall together all of a sudden. At the very least, the information about the gait-keeper gene is interesting, whether or not it actually applies to my horse. What a cool discovery!

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Comment by Wendy Koch on May 31, 2013 at 5:28pm: I don't think she's lost nervous pathways. Based on the description of the gene, I think she had to learn how to move, and because she grew up in a pen, that learning was delayed to a point where her ability to adapt was affected. She has definitely improved from where she was when I got her, but I don't think she'll ever be normal. Continuous improvement is probably the best I can hope for at this stage.

I don't think her falling affects her flightiness --- only the reverse. The flightiness may also be a product of growing up in a pen, and her reactivity has also improved since I first got her, but I think that genetics and epigenetics are probably also involved. It's a pity because she's a superb jumper (or was until she got carpal tunnel syndrome), but she won't even enter the ring if she's not used to the jumps (and changing anything makes it a whole new jump).

Comment by Jackie Cochran on May 31, 2013 at 4:07pm: This is why I suggested the Spanish Walk.

I've lost nerve pathways due to my MS. I have been able to grow new nerve pathways to take the place of some of the ones I've lost. It sort of sounds like there is a "misfire" in the nerve that brings the foreleg forward, possibly a nerve that goes from the arm to the scapula over the shoulder joint. It will take TIME, lots of time to grow the new nerve pathway. You will have to get the mare to move the foreleg forward in response to your signal, start of just a few times each foreleg and then gradually increase, this will create the demand for new neuronal growth.

Just like riding horses gives me regular exercise in losing and regaining my balance and in strengthening the muscles necessary to keep balance, I do think that Linda's exercises can help your mare. If I remember correctly Linda has helped many "clumsy/careless" horses more better. Part of the reason is that the horse has to move in a new way SLOWLY, giving the horse practice in planning out each step.

I also think your mare has a vicious circle going, because she does not automatically know where her feet are she is super reactive to any percieved possibility of a predator. This causes her to take her attention from her feet, which causes falling, which proves to the mare that her paranoia is valid, adding to more flightiness. IF it is possible to teach her how to move effectively it might reduce her flightiness a good deal since she could be confident of her ability to escape dangerous predators.

Many, many years ago I had a colt whose elbow suffered a green-stick fracture from a kick. The break took 6 weeks to heal, then I was faced on convincing the colt who had been dragging the injured leg that he could walk on it again. At first I had to lean down and bring his leg forward, plant his hoof on the ground, and make him go forward a step. It took another two? months of doing this daily until he started bringing his leg forward on his own. And then one day I came into the pasture and the colt walked to me on all four feet after four or so months of walking 3-legged.

Your situation and your mare is different from the above, my colt and his body had "forgotten" he could walk using the injured leg, your mare needs to learn to pay attention to where she feet are and how to coordinate them properly. You may be able to help your mare quite a lot, maybe even enough to make her a safer riding horse for you.

You haven't given up on her, good for you!

Comment by Wendy Koch on May 31, 2013 at 3:07pm: <There are times that if I do not pay attention a leg just threatens to collapse under me.>

That sounds very similar to what happens with Tori, except it doesn't feel as if the leg collapses. It's as if it just disappears. That's why I think she's not getting it where it needs to be.

She loses track of all four feet, but it's the front feet that cause the falls. She's come pretty close to sitting down a couple times, but I don't remember any falls when it was just her rear end that disappeared. I think it's easier for her to recover when her back feet don't go where they should.

Good luck with the MS. I have a friend in CA whose horses are her PT, too. Can't think of a better therapist!

Comment by Jackie Cochran on May 31, 2013 at 2:32pm: If it is the front feet that she is losing track of training for the Spanish Walk (from the ground) may get her attention focused on what they are doing. Then you develop it under saddle. It would give you something to distract her attention from her flightiness and get it back to what she is doing with her front feet.

But I still think Linda's techniques may be the best for her and you since if you do them all it really gets the horse to concentrate on what they are doing.

You see I have the same problem, because of my MS I have to pay attention to every movement of my feet. If I do not I often trip and sometimes fall. There are times that if I do not pay attention a leg just threatens to collapse under me. I had to learn to do this (pay attention), and riding horses really helps me with it. Riding horses is my physical therapy (cheaper than human PTs) and it has gotten me out of and kept me out of a wheelchair. I still need two canes but at least I can walk safely on my own two feet, so long I pay attention.

Comment by Wendy Koch on May 31, 2013 at 1:54pm: Thanks for the reference, Jackie. I'll have to check out what Linda says. My mare has gotten a lot better about knowing where her body parts are, but I think her gaits are as good as they're going to get (which isn't all that good).

Tori tests out as perfectly okay from a physical standpoint. I think she just has to concentrate on every step she takes, and sometimes, she loses that concentration. She's the flightiest horse in the world, too, so she's easily distracted. It had always seemed to me that, at some point, moving should become more automatic, but after finding out about the gene, I think she's probably reached her limit for automatic, and now, it's just dependent on her paying attention to her feet --- and it's impossible to pay attention to every single step you ever make.

Whether or not she's on contact doesn't make much of a difference. Keeping her collected doesn't keep her from falling if she doesn't put her front feet down. If I have enough warning, I can keep her head up so she doesn't somersault, but I rarely have any warning. It's not like a horse tripping, where you're still upright when you start the fall. In Tori's case, you don't know yu're falling until the up phase of the normal head bob doesn't come, and by then, my face is usually only a couple feet off the ground.

She is definitely a dangerous horse to ride, and for that reason, I don't let anyone else ride her. I'm a glutton for punishment, though. With all her faults, I still enjoy riding her, so I don't plan on quitting any time soon. Hopefully, we'll both survive the experience. :-)

Comment by Jackie Cochran on May 30, 2013 at 6:05pm: Oh, I forgot to tell you something. In the book "The Ultimate Horse Behavior and Training Book" by Linda Tellington-Jones (ISBN-978-1-57076-320-5) she has thorough discussions with lots of pictures of how to teach a horse how to keep track of his body. This does require a good bit of ground work but it may do your mare A LOT of good.

Comment by Jackie Cochran on May 30, 2013 at 5:04pm: Hi Wendy, thanks for the reference to that article! It is very interesting.

I once owned a Paso Fino mare from weanling (she had LOTS of turnout in a pasture), and a 7/8 Arab 1/8 Saddlebred mare. I only saw the Paso Fino mare trot twice in over twenty years and she had a very, very, very pacey canter. The 1/8 Saddlebred mare was stricty walk, trot and regular canter/gallop until I gaited her (fox-trot) in her teens. I also gaited three pure Arabians (fox trot) who had super over-stepping walks, and regular trots and canters/gallops.

On the other hand my Anglo-Arab gelding (closely related to two of the Arabs I gaited) had absolutely no gaiting ability, and an Arab-Welsh mare I ride also shows no gaiting ability.

I am worried about your horse falling. In over four decades of riding I have had TWO horses fall on me, my Anglo-Arab gelding whose feet slid out from under him on wet grass at a canter and never fell again in his life, and when an old Arab mare with bad knees took a bad step (I stopped riding her after that!) My Paso Fino mare never fell. She was probably the most sure footed of all the horses I owned, she always had an extra foot to spare when she needed one. Many gaited horses are used for riding in the mountains and I have never heard of a propensity to fall from any of them, tripping yes, but not falling.

Get your horse seen by a veterinarian!!!! Get her tested for all the neurological diseases.

If you ride her KEEP HER ON CONTACT, that will make it easier for her to coordinate her body. You will have to take over responsibility for coordinating her leg movements too. I would not ride her until you have found out what is wrong, and when that is fixed you will still have to take responsibility for her movement while riding her for a long time. Sorry, I've had horses with this gene and they do not tend to fall under their riders frequently at all. And yes, we did go fast up and down hills riding in fields and on trails, both on contact and on loose reins. Her upbringing is a factor here, but it does not explain the frequent falling.

I think you are right that your mare may well have this gene.