Ok, I know this is random, but my mare is having a week long heat cycle in December! She had been bred over the summer, resulting in an early loss (3 months). Prior to breeding her cycles were very regular, but only "noticeable" for 3 days. Obviously she showed much stronger when at the stallions' barn. My problem is that now there is a stallion in my barn, and she has been in standing heat for 8 days. She can't even be turned out during the day as he has jumped the fence before when he was a yearling, and I do not want her bred at this point in the year. Is this a true heat? Could it be a false, non-ovulatory heat? I am in Northern New England, and find it hard to believe she is cycling in the winter. Could this be because there are hormones in the barn now? Is 8 days really regular for a mare to cycle? At what point do I say enough is enough? Does this mean she will cycle all winter? I would appreciate any help you have. Thanks. Trisha
Posted on Sunday, December 09, 2001 - 01:16 am:
Mare's cycles vary tremendously, and without ultrasounding or running hormone assays, it is difficult to say with certainty whether your mare is anovulatory or not. Certainly some mares do display estrus year-round, but are not ovulating in the winter. A minority however do continue to ovulate.
An 8 day estrus at this time of the year would not be unusual, as lack of regularity is typical in transitional phases or when related to anovulatory estrus. Another possibility is that what your mare is showing is a "behavioural estrus" which is actually a sign of submissiveness.
Not sure if this really helped.....!
Posted on Monday, December 10, 2001 - 10:30 pm:
Hi, original poster here. Would the behavioral estrus be because the stallion was brought onto the property? And would it this effect her normal estrus come spring? I am planning on re-breeding her in the Spring, so I am interested about whether this will enable me to start earlier than I would otherwise. I suppose what I will do is ultrasound in the Spring to verify what has been going on, and just keep her well away from the stallion for the time being! Anyway, thank you for the input! Trisha
Posted on Monday, December 10, 2001 - 10:37 pm:
It's quite possible the behavioural estrus was induced as a result of the appearance of a stallion.
It doesn't actually affect estrus - it's a submissive behavioural response, not hormonally caused, so it will have no effect on breedability, except it will make estrus determination by teasing a little more difficult. She can even still be in winter anestrus and yet appear to be in estrus as a result of the response.
I'd have her ultrasounded now if she is still showing this behaviour - it might save some confusion in the spring when you're trying to breed!
Well, I haven't seen her in a few days, so hopefully it is over by now. If not, I will call the vet and have her checked out. She is 18, so maybe she is just going a little whacky with old age. Actually, while I am thinking about it, I know older women can get "sticky chromosomes", causing genetic abnormalities. Do you know if something like that happens to horses? My vet reviewed her biopsy after she lost her foal in October, and said she is a 2A, and that her post loss Ultrasound looked great, well resorbed, no fluid, good tone, etc, so all she could figure was that there was a genetic abnormaility with the foal making it non-compatible with life. Is this possibly because she is older and has sticky chromosomes? She concieved very easily, but I am still worried about putting a lot of time and money (and emotional investment) into breeding her when it may not prove fruitful. She has a lot to offer as a broodmare, really nice conformation/movement (8 for gaits at one horse show), and the best personality, she is the barn favorite! Anyway, back to the original questions I asked, and your subsequent answers, I intend to have her cultured (obviously pre-breeding) in Feb or March depending on who she is being bred to, and how she is being bred. I will most likely have her ultrasounded then at the very latest. Also, my vet had recommended not re-biopsying her this spring. Is this an accepted practice, or can the grade change dractically from year to year? This will be my first foal, and I really just want to do it right. Again, thank you for the info, this has been very helpful for me. Trisha
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