At some point over the last few years, my friend Melissa’s mare Misty started moving off awkwardly when first mounted. She flattened her croup and left her rear legs “behind” as she moved off. She appeared to walk on the toes of her hind feet. After anywhere from a few seconds and strides to a minute or so, she would be fine. See the video below for one of her worst episodes.
Jump to suggestions received in Facebook comment thread
She doesn’t do it all the time, and the severity varies. It’s definitely worse when she’s in or near being in season. It doesn’t happen in winter, and it’s worse in spring. It seems to be worse when her hocks are due for injecting (maybe).
I’d seen the mysterious pain after mounting before…
I had seen this pain reaction when I was at the racetrack in Spain. Always in fillies–even young ones. The youngest I remember seeing do this was two-year-old, not yet raced. I never saw it in a colt. It was more common in nervous fillies. Coincidence? Or perhaps nerves led to pulling and excess speed, and therefore injury? Or hormonal issues caused both nervousness and post-mounting pain?
I remembered wondering about the cause decades ago. I asked about it, but no one gave me a satisfactory answer. The fillies/mares were otherwise sound, and the soreness always wore off quickly. By the time the fillies had taken a turn of the courtyard, they were walking normally. It didn’t help to ride without a saddle (with just a foam pad and overgirth).
Because I never had a horse of my own do this, I was never in the position to ask veterinarians about it. In those days, i was for the most part a mute observer, trying to learn as much as I could without interfering. But I did wonder…
Searching for an explanation
When Misty started showing this same kind of pain after mounting this last year, it reminded me of my experience in Spain. posted queries about it on various Facebook groups. I received a lot of suggestions, few of which made sense in light of the original post (so rarely read! See my funny blog post about How to discourage questioning in online horse fora.)
The suggestions included… It’s the saddle (it fits). She’s got ulcers (see below). She needs to be out 24/7 (she it). She needs more work. She needs less work. And so forth. No veterinarian offered a suggestion. I believe Misty’s vets have been consulted, but they have never seen the phenomenon in person. We still don’t know what’s going on.
I’m hoping if I share this post widely enough, someone will know what’s going on and be kind enough to leave some feedback in the comments, preferably on this blog where everyone can see it.
Misty’s history
Melissa does just about anything with Misty. Misty has completed two limited distance endurance rides. She does trail rides, local shows, lessons, and working equitation (see Misty in my post about a Working Equitation Cow Clinic).
Misty takes care of herself no matter what she does, 25 miles in under six hours, dressage show, clinic, working equitation. She never goes off her feed or hay or water in these situations.
Misty is colic-prone and has had regular bouts. She is weather-sensitive and will stop drinking and possibly colic in response to barometric changes. She also is prone to colic when in heat (and has ferocious heats). She is somewhat post-legged and has had hock pain (she is injected when necessary). Her lower legs are sound. She occasionally needs osteopathic adjustments.
In early 2019, Misty had a near-death experience: colitis. After a long stay at Interstate Equine, she came home and began a long recovery. Melissa changed her diet. Before she received a handful of Nutrena Safe Choice Original (she’s a very easy keeper) and free choice grass hay when pasture was not abundant (plus beet pulp when we trail rode or trained for endurance), plus Smartpak Joint Supplement.
Current feed regimen:
Misty eats soaked alfalfa cubes and Triple Crown Lite, plus grass hay and pasture as before. She also receives Smartpak Smartflex ultimate joint supplement, Alimend gastric supplement, four 1000 mg TUMS, Mare Ease, and a Vitamin supplement (all twice a day). Melissa gives her Uldergard when trailering or around barometric changes.
Any ideas?
Please share them! If you are a vet and can tell us what’s going on, we’d be very grateful. If you are a horse owner or caretaker who has seen this before, we’d love to add your experience to this blog.
Suggestions received in Facebook comment thread
The following is the comment thread with suggestions provided by an expert in reproduction, Kathy St. Martin (Equine Reproduction, LLC) and Melissa’s responses.
Kathy:
Seems easy enough to check by simply having an ultrasound done when she’s at her worst and at her best. If it is indeed cyclical, have her ovarectomized (ovaries removed). We see discomfort fairly regularly when mares are in estrus and some mares grow pretty significant sized follicles. Sometimes breeding will resolve the problem, but more often than not, it’s just discomfort that will continue.
Melissa:
She’s been ultrasound during heat and nothing unusual. I’ve done the oxytocin to stop her heat cycle for several months and that helped a bit. Vet didn’t recommend spaying her.
Kathy:
Oxytocin does NOT stop her heat cycle. Indeed, it causes smooth muscle contractions and may actually cause cramping. If you mean Regumate/Altrenogest – mares can and do develop follicles and will ovulate while on it, so that may not work, either. You “could” try using P&E (progesterone and estradiol) as that inhibits ovarian activity.
I am not expecting for you to find anything “unusual” during her heat but more to get an idea if she is painful when in estrus due to follicular activity. Some mares are very painful when if estrus and indeed, it is an indication of imminent ovulation when the ovary with the dominant follicle is painful upon palpation.
Melissa:
Yes I think she is just painful when in heat. For some reason vet didn’t want to do spaying. Said he’d spayed mares like her before and some of them still exhibited the same issues. So he suggested this, it worked for a bit.
Other suggestion was to just administer bute when she is in heat. But definitely can’t show if I do that.
Her colic usually was around February with swinging temps and first heat cycle.
Her first is usually pretty bad, lots of squealing, and winking and running around. Deep nickering. She’s not rideable at all. But not aggressive to me.
Kathy:
the problem with that protocol is that it “is” essentially short term. It is prolonging the resolution of the CL, but not indefinitely. So your mare “will” return to estrus. Additionally, mares can and do develop follicles in the face of progesterone – so if that’s the case, it won’t help in accomplishing what you are trying to do – STOP all follicular development.
You state that her colic was usually in February – from what you are indicating, she would be transitional at that point and there would be no CL which, if you were trying to use oxytocin to prolong the CL, would be useless as there would be none present. There is an injectable form of Altrenogest, as well as an Injectable form of P*E both of which you can purchased as a long acting formulation. I would suggest trying the long acting P&E for a few months to see if that resolves it or lessens it. It’s less invasive than a lot of other things and would give you an indication of whether or not it “is” related to the ovaries.
The problem with some of the things that are being presented to you are used to prevent estrus display and not the entire estrus cycle. Not sure if this is making sense. What I am proposing is that you need to stop the development of follicles. That means you need to suppress the mechanisms that cause that. Altrenogest, marbles, oxytocin, etc., do not typically do that. Mares can and do ovulate in the presence of progesterone – indeed it is an essential part of pregnancy maintenance.