Off and on lameness

Question
QUESTION: Hi Judi,
I read some of your other answers on lamenesses and figured you might be able to help me out. I have a 9-year-old standardbred mare (pacer) who raced from 2005 to 2010. I adopted her 2 months ago and have been starting her under saddle. She had a hoof abcess diagnosed by a farrier in her right hind about 6 weeks ago, but after treatment was a lot better.

More recently, she's been going lame off and on every few days. On her good days, this mare is full of spunk, like a true racehorse. She loves to work, and has a huge trot.

But on her bad days, she doesn't want to work beyond the walk, although I can push her to a slow trot. Lunging to the left, she bobs her head just slightly, but it's so slight that it's hard to tell if she's going up on the right fore or down on the right hind. Circling to the right, she doesn't appear lame, but definitely stiff and reticent.

I've been wondering if this could possibly be arthritis, as she has no obvious injuries, heat, swelling, etc. Her abcess isn't completely healed, but doesn't seem to cause her pain on the good days...

She also has some scarring on her left shoulder and both forelegs are thickened, the left much more than the right. I had the vet out for a Coggins test and he said she may have had a fall at the track, but we didn't manage to get a complete lameness evaluation done at that time. I know it's probably worth getting a complete lameness check but I was hoping you might know what might be causing this on and off lameness/stiffness. Thanks in advance!

ANSWER: Hi Jess -

First of all, congratulations on your new acquisition and bless your heart for adopting this mare.  So many things come to mind as I read your question.  Your recount of her history was excellent and very informative.  As you probably already know, anything that happens intermittently is awfully hard to diagnose and her prolonged racing career makes that even more difficult.  With so many possibilities, all I can really do is think out loud and speculate as to what's happening.  I agree with you 100% that a complete lameness exam would be money well spent but the first thing that came to my mind was actually navicular so be sure to get a good set of x-rays of all four feet.  Navicular syndrome is aggravated by repeated compression which can degenerate the cartilage.  It is also common in horses that spend most of their time standing in a stall versus being in a paddock.  Both of these scenarios are common for racehorses.  Navicular often starts out as a mild or intermittent lameness that progressively worsens.  Your farrier may even be able to give their opinion/advice but x-rays will give you a positive diagnosis. Again, this is just my initial guess based on the this mare's history.

I hope this helps Jess and I'd love to hear what you learn from your veterinarian after her lameness exam.  She's a very lucky girl to have landed in your care and I wish you the best of luck :)


Thank you!!

---------- FOLLOW-UP ----------

QUESTION: Hi Judi,
Thanks for the quick response. I hadn't really considered navicular. I had a QH who was navicular, so I have some experience with this disease. He was already moderately advanced in the disease when I acquired him and he improved so quickly after getting corrective shoes, that I never actually had him x-rayed. Also, he was definitely predisposed to the disease, being 15.3 hh, 800 lbs and only a size 00 hoof with very straight pasterns.

On the other hand, this mare has a good size hoof (size 2 shoes) for her 15.3 hh, 1000-lb frame and a normal slope to her pastern. But you're probably right about standing in the stall: Despite her high energy level, this mare has absolutely no clue what to do with herself when turned out, which leads me to believe she has no experience "self-exercising".

I was wondering if it might have to do with shoeing as well, since I get from your answer that the abcess is probably a non-starter as a cause at this point. From talking to others in the Standardbred rescue community, for racing horses, apparently they tend to let the hooves grow very long in the toe, with flat soles and heels. My farrier has tried to straighten her up to an angle more in line with her pasterns over the course of her last 2 shoeings, but I thought this might be causing her discomfort, since she's not used to it. She was bad for 3 days after his last visit, then sound for 2 days, then lame again yesterday.

Sorry for the rambling, but it's a case of "not-quite-right" and I'm lying awake every night thinking about it until I can get some time off work to get the full lameness evaluation done. In the meantime, do you think it's all right to keep working her on her good days? I usually lunge for about 10 minutes, and ride for about 15 minutes, just at the walk and trot, since it's all pretty new to her and I want to install some controls before we progress beyond the trot, which is already quite fast enough!

Thanks again,
Jess

Answer
Wow Jess, she does sound like a good-footed horse right?  I'd give anything for a size 2 foot!  But the way you describe how she had been shod flat footed with long toes makes it easier to see how she could have been pounding away at her poor heels for years.  Do you notice her trying to land toe first when you're lunging her?  Do both of her front feet look like they are the same size and shape? Her soreness may be coming from something completely different and may not even be navicular but I think she has several indicators that make it a possibility for sure.    

Anytime a farrier changes hoof angles I think it's really common for a horse to become sore as tendons and muscles adjust but it's been my experience that it's more of a daily pain that starts off bad and progressively gets better without coming and going like this mare is exhibiting.  I guess working her lightly on her good days would be okay ... you sound like you would be able to make the right call on that depending on how hard the footing is in your schooling area and her general attitude.  

You write so well Jess and I enjoy reading your questions ... love the part about installing some control and the whole not knowing what to do with herself when she's turned out ... made me laugh out loud and I had the best visual :)  

It's a bit slow in the office today so it's been pretty easy to catch your questions this afternoon.  I'll be heading home in about an hour.