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  1. #1
    Join Date
    Nov. 24, 2010
    Santa Fe, NM

    Default Young Mare in Constant Heat--Senovex or marble or ???

    Greetings wise friends,

    In March I brought home an underweight 4yo untrained mare, Egyptian Arabian X Irish Draught, from a less-than-idea backyard breeder situation. She has since received top-notch care, been vetted, great progressive work by the farrier, put on a nutrition program and gained 100 pounds and gained a healthy shine and enough energy to become a handful. I also began training her, and she is well started in the program, developing a topline, has exactly 40 rides, and lunges, bathes, cross-rails, cavaletti, etc. Her trajectory is planned to be to start low-level eventing and fox-hunting and pretty regular work of the funnest variety.

    She has been in season (heat) since arriving here. When I had the vet out for the initial visit 3 days after arriving I had her checked for pregnancy (palpated-just in case!) and she was in season. Since moving to a new barn can bring on heat, no big deal, I was just glad she was not preggers. But she has been in season constantly, ever since. This is not an exaggeration--barn owner, barn manager, barn help, vet, and I all agree she is in heat full blown, daily. I ride/work her 5-6 times a week and since I've only ever seen her in this state, I have no baseline to compare her too, although I can tell you she isn't an easy horse. She is a huge handful (understatement). We've made great strides, but when I told the vet I'd put 40 rides on her, all while she was in this state, I got the "You're braver than I thought" look. At the very least she is amped up and distracted and unable to focus and enjoy. She may be in some level of pain, as she is hot and jumpy and very reactive to the leg. Since I don't have any baseline I don't know how much of this is the heat cycle she's been constantly in. She is not all nightmare--she is clever and athletic and does enjoy the stimulation of work and loves the attention.

    So it is time to do something about it. Vet has initially recommended SYNOVEX implants, but with just a little preliminary research I found much reason to question their effectiveness and appropriateness. (See Also Regu-Mate has been mentioned, but usually in the context of keeping a mare from estrus, not knocking her out of it. I have also heard about the marble method, but find scholarly references only citing 35% effectiveness (and that is for suppressing estrus that a horse in not currently in yet), although the side effect profile of that method is pleasing to me (almost none).

    Also, it seems to me I need to request a full array of diagnostics before we talk treatment to see if a tumor or something is causing this odd long heat cycle. Shouldn't I?

    I have no breeding aspirations for the mare, although getting her spayed seems extremely invasive and not at all certain to even affect her estrus rut.

    What can the collective COTH wisdom share with me? I have the vet coming out July 5, I am committed to helping this mare feel "normal", I just need to have an intelligent game plan.
    At all times, we are either training or untraining.
    Flying Haflinger blog: Flying Irish Draught blog:

  2. #2
    Join Date
    Nov. 17, 2008


    Unless she's bonkers and out of control driving you crazy and can't focus/screaming/hollering/and squatting and squirting everywhere don't do anything

    What has worked wonders for my mare was Injectable ReguMate ... 1.5cc's IM every 12 days!

  3. #3


    I have this exact problem with my 4 y.o. paint. I have looked everywhere trying to find a solution. Tried mare majic this spring and it actually seemed to work. I had a gal trying her out and she had her for a little over two months through the summer, she kept her on mare majic. She said she didn't show in heat the whole time. I had her stop the mare majic about a week before she came home since we were getting into fall and I figured she'd be less likely to be in heat much. A week after being home she came back into heat and seems like she hasn't gone out. I put her back on the mare majic and it didn't do anything this time. Being a paint and her back end mostly white it doesn't look to nice when she is so messy while in heat. I noticed she is also very sensitive about everything when I ride. My leg cues she over reacts, she's more spooky/jumpy which was not like her at all when I had her trained. One plus she is still very sweet while in heat, never mean or nasty to other horses or people and really isn't overly flirty with my gelding. This week I finally took her to the vet and had her ultra sound to make sure there wasn't more to it, such as a cyst etc. Her ultra sound looked fine so they took her blood work so I am waiting to see if that tells me anything. I had my vet check with a larger vet to see about sterilization, that cost 800-900 and I'm not guaranteed she still won't show in heat. All I do is trail ride and I feel bad when she is so messy, I feel like she has to be uncomfortable. So any suggestions I'd appreciate. Regumate sounds expensive, so I'm debating the marble.

  4. #4
    Join Date
    Mar. 9, 2003
    Baldwin, MD


    This screams granulosa cell tumor to me - they produce constant estrogen (and thus constant behavioral signs of heat), and can produce other hormones like testosterone and progesterone in excessive concentrations as well. Mares at this point (December) should be fully in seasonal anestrus with tiny, shriveled ovaries and kicking at any man in sight.

    Granulosa cell tumors (as long as they're not in super early stage) can be easily diagnosed via rectal palpation and ultrasound - the contralateral ovary gets super tiny and shriveled when the ovary with the tumor takes over.

    1 members found this post helpful.

  5. #5
    Join Date
    Mar. 9, 2003
    Baldwin, MD


    Oh snap, just realized your original post was from June. Any updates on this critter?

  6. #6


    Hey Lauren,

    I commented on this just friday, if you could read my comment I posted right before yours? Any help I'd appreciate it, still today ( I live in Iowa) she is messy. The vet is to get back to me today/tomorrow with her blood test results. You can also email me @ its easier for me to get it then coming back here.


  7. #7
    Join Date
    Dec. 10, 2012


    I had a similar issue with my Quarter Horse mare. She was in almost constant heat and seemed to be in pain or at least uncomfortable when she was. A vet in our area specializes in reproductive work and came out to ultrasound her. He found nothing. We used supplements and herbs to help manage the problem for about a year and a half. It helped at first, but gradually she continued to get worse. One day we noticed her displaying stallion like behaviors and even worsening heat cycles. We called the vet once again and discussed the options. He recommended regumate, but we absolutely didn't want to deal with the potential consequences of that stuff. We then discussed the marbles. He actually did not have a strong recommendation to do this. From his experience, the marbles are only effective part of the time, are expensive, and worst of all have the ability to shatter in the uterus! He also had concerns about the stallion like behavior she had been displaying as that is a key symptom of an ovarian tumor. He said that he would like to blood work to make sure it wasn't a tumor, but if it was that they would have to remove the ovary that it was affecting. Because we had no desire to breed her, we just opted to go with the surgery. It was the best decision we ever made for her! When they did the surgery, they found a hematoma the size of a softball on one ovary. it took quite a bit of time and some rehabilitation for her to recover for the surgery, but she's turned into such a happier, easier to ride horse. I never have to worry about her being in pain anymore and she now works as a lesson horse. The surgery may be a little expensive, but it's well worth the relief she'll get and it'll eventually pay for itself if you go with the marbles or regumate.

  8. #8
    Join Date
    Jan. 26, 2007


    I'm not sure a marble is the answer to your problem. I think some of the other recommendations should be explored. For others in a different situation, our vet gave a different opinion on marbles. He thought it was worth a try in our case and it was very successful. He thought it was a safe option to try (no drugs, no surgery). It cost $25 for the marble and about $40 for him to insert it and $40 to take it out. The marble is reusable so in the long run that was cheap. Use a quality marble and I don't think shattering is a likely scenario. Maybe some repro experts could comment?

    We then discussed the marbles. He actually did not have a strong recommendation to do this. From his experience, the marbles are only effective part of the time, are expensive, and worst of all have the ability to shatter in the uterus! [/QUOTE]

  9. #9


    Thanks for the suggestions. My vet did call me yesterday, said her blood work was all normal. Since I did have her ultra sounded, could they have missed a cyst on her ovary by chance? I did discuss the marble, she said it has a 41% chance of working, I did read up on a study where it showed how many mares kept it in and how many couldn't keep it in. I think she said it would be around 100 to do it. I just feel like something is not right with her constantly having a discharge, it starts out dark brown/red that runs clear down to her feet. I noticed also this fall her having like a milky/creamed color that would just stay between her butt cheeks. She is NEVER mean or nasty while in heat but she is super sensitive to my leg cues and over all just goosy about weird things that normally wouldn't even phase her. If she sees a weird looking plant, she'll jump and look at it, there was a tiny wash out in the field this spring. I mean tiny, maybe 8" deep and 8" wide if that and you would of thought I'd have asked her to jump a huge hole with something scary in it. I fought and fought with her to go over it, since I didn't want to give into her. This was all completely out of character for her. When I had her trained my trainer took her through all kinds of rough terrain and when I got her back I took her to Shimek Forest and she was a dream, she did better than my old, well broke horses. She crossed ditches, logs etc without any hesitation. The next spring at 3 she did great even after sitting all winter, but this spring its like a totally different horse. I have two other mares and other than them being a little squealy at times I wouldn't even notice them being in heat. It's just so frustrating, she's such a beautiful paint, with a wonderful disposition but then she has all that gross stuff down her back end that is not easy to clean off and then I feel bad riding her if she is in heat since she's so sensitive.

  10. #10
    Join Date
    May. 26, 2005


    I had a mare somewhat like what you described... x100. We are talking hellbitch status here, constantly in heat and seemingly in pain. From the time we bought her, her condition progressed to the point we decided to drive her to Auburn University in order to have her ovaries removed. We tried Depo Provera injections for months and saw no difference, prior to this decision. Initial ultra sounds did not see anything, I told them I wanted the surgery anyway.

    Next day I get a call from the surgeon saying they had never seen anything like the massive cysts they pulled out of her. She had probably been in pain her whole life (6 y/o at the time). It completely explains her aggresive, difficult behavior. It has been two years since, and we have seen drastic improvements in her. I no longer own her, but have kept up with her progress and do not regret the decision at all.

    Just something to think about if you are not planning to breed.
    Thoroughbreds: classic

    Turn. N. Burn.

  11. #11


    My vet did contact a larger vet about sterilizing her. He said he could but I would not be guaranteed that she still wouldn't show signs of being in heat, which I found odd? She is never nasty which I am thankful for, just touchy. I think I will try the mare majic again starting in Feb. and see how that goes. It worked this spring/summer til I took her off. If that doesn't work, I will try the marble and if that doesn't help, I guess I'll try sterilizing her. I didn't plan on breeding her, just would be an option if ever down the road she came up lame I could get a nice baby out of her.

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