Hi all! I was sent here by a poster on another board I belong to. Hopefully someone can help me out!
I am on year #2 of trying to breed my 11 year old maiden mare. We tried last year in May. It was a last minute "try", as she had just recently been injured and her show career ended, and we wanted to give it a shot before the stud started his busy show season just to see if we got lucky. My vet at home ultrasounded her to make sure everything was in working order, and cultered her to rule out infection. I was given the go ahead, and shipped her to the breeding farm.
She was inseminated soon after getting there (they check follicles and ovulation via ultrasound) but unfortunately didn't catch. When she cycled a 2nd time, I was told her follicle "disinigrated" and there was nothing to breed on, so she was not bred a second time. Due to the stud starting show season and us not having the time to short cycle her with drugs, I took her home.
Fast forward to this year: The mare has had a whole year to "be a horse", including going on turnout. I put her under the lights in November (16 hrs a day), and she had shed her winter coat by late December. On New Years Day, she teased to my gelding and appeared to be in heat as she was "winking" and peeing in the aisleway when I walked him by. I shipped her to the repro vet again, along with her lights.
Initially when I got her there, they said she had a good sized follicle and was coming along great, and they planned to breed in a few days. She was checked two days later, and still had a good sized follicle. On the actual day they were to breed, she was ultrasounded, and her follicle had "regressed" pretty much back down to nothing. The vet thought she might be in transitional heat (I don't really get this as she had been under lights for so long). They let her try to cycle on her own again and the same thing happened- started a good follicle, and then it shrunk but she never ovulated.
She was then started on 14 days of Regumate, and then given an Estrumate injection. I was told by the vet that this would stop whatever irregular "cycle" she had going on, and then the estrumate would force her to ovulate. Not the case! She had started a follicle and teased weakly to a stud, and then when it came time to where breeding might be likely, the follicle had regressed again. She was given a second Estrumate injection, and nothing happened. Her follicles grow and look promising, but never drop. I looked at the vet notes, and her biggest follicle was a 32. They even tried stabling her next to a stud, but my mare never seemed to get interested in him (although I have seen her act like a hussy in the past lol so I know it's possible for her to be interested in the boys!)
The repro vet is stumped. This mare is in otherwise healthy condition, without infection, etc. I asked about bloodwork being drawn for testing and was told that there was really nothing to test her for. He said that if she had a hormone problem, either she would not have any follicular activity at all, or she would have a follicle that never goes away. He told me I could leave her there and we could keep trying drugs (she had been there over 2 months), or I could take her home, get her out in the sunlight, and see if she did better in her home environment. (She did not appear to be stressed out at the breeding farm but who knows). He said that sometimes mares do this for a short time, but he has never had a mare do it to him for 2 years in a row. (I should note that she was only at his clinic from April-May last year and from Jan-Mar this year). We did not try checking her in the summer months because of the stud's busy show schedule and the fact that I would be paying board at a repro facility for her just to hang out with no stud to breed to if she did happen to come into heat).
Is this normal? Anybody have any tips? Is it possible that I just own a mare that doesnt ovulate, even though there is nothing wrong with her per two vets ? I have seen her in heat many times in the past, but at the time we were showing and not breeding so I wasnt tracking it or anything. I feel so discouraged as it is looking like I may never get a foal from this mare and it would mean so much to me (in sentimental value especially) if I could.
Anything I can do, or give? She is on LifeForce supplement, and has been for a year, as I was told by my vet at home that mares have good conception rates on it. She is on turnout at home for a few hours a day in a round pen (but was not on turnout at the breeding farm). The plan is to have my vet at home check her next week just to get a baseline and see what he thinks. We will ship semen if she does happen to ovulate (cooled, not frozen- same thing she would get inseminated with at the breeding farm except obviously I will have to FedEx overnight). I didn't plan for this to be an easy road but I am really feeling down about this right now.
It is still early in the year and there is always the possibility that the mare is in transitional phase. Even if she has been under lights this year, there are a handful of mares that fail to respond as predicted, and there are also possible issues that can have a negative effect on phototropic stimulation such as the lights going out for 3 consecutive nights (the bulb fails or there is a power cut), or if she was able to get her head over the stall door and into the darkness, or if she was brought in to be put under lights after it had started (only started mind you!) to get dark out. All of those can result in a failure of timely onset of cyclicity despite a lighting program.
Presuming that those are not factors, the next thing to consider is that during winter anestrus or transitional phase, mares can show apparent receptivity to a stallion (or gelding) but in fact not be in a truly cyclical condition - and therefore not ovulate. This may explain her apparent receptivity on New Year's Day.
Fast forward to now... The first thing I think I would do would be to run progesterone assays - up to three of them a week apart. If you have progesterone levels >1 ng/ml in any of those assays, then the mare is ovulating (and you can stop doing more assays!).
While Regumate may suppress receptivity to the stallion, it will not necessarily suppress ovulation, so it cannot be relied upon completely to produce a timely breedable cycle. While Estrumate (Cloprostenol) may stimulate an ovulation, early in the year - particularly if the mare is transitional - it will be less reliable for doing so (it is in fact usually used to destroy the CL and cause a return to estrus, not to promote ovulation).
My inclination is that she is transitional. If she were my mare, I would probably wait a month or two before trying to breed her again, although you can monitor in the meantime if you want. Certainly doing the progesterone assay will be a good starting point, which you can do immediately if you wish.
In the event that the mare does show elevated levels of progesterone, you might want to consider using biorelease P&E or biorelease altrenogest (referenced in that same linked article) which is far more reliable than Regumate for pinpointing cyclicity and ovulation.
I would also be conscious of the possibility of a lack of cervical relaxation resulting in retained uterine fluid. This should be carefully monitored during estrus and the use of an oxytocin protocol considered.
Note that although your mare has apparently had a uterine swab culture prepared and read as "clean", a cytology smear is actually more important and you should make sure that one was prepared and read in conjunction with the culture.
Overall, I suspect that a little tincture of time and close monitoring with good reproductive management is going to be your solution.
Neither Cloprostenol ("Estrumate") nor Altrenogest ("Regumate") will assay as progesterone, so other than the fact that if she had a functional CL present (which would be secreting progesterone that would assay) when she was given the Cloprostenol, she would have returned to estrus (so progesterone levels dropped to <1 ng/ml), they will have no effect. In the event that she did return to estrus after a CL being destroyed by the Cloprostenol, then within about 2 weeks she would have likely ovulated again and have another functioning CL present, which would be secreting progesterone - hence the need to do assays weekly for 3 weeks.
If she is producing follicles >30 mm in diameter, along with good levels of uterine edema, then the use of Deslorelin or Histrelin (the latter is what we prefer) may have a positive impact on promoting an ovulation.
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