i have a miniature donkey who is five years old. I have a 3 year old minaure stud. he breed her in august and no luck,( they are pastured together) today i saw them doing there busineess. short and simple cant mares get pregnet in november do they stop cycling??????/!!!!thanks
While some mares may cycle year round and ovulate (and therefore be fertile) the stimulus that causes winter anestrus (or the onset of regular cyclicity in the spring) is light duration not a stallion. Hence, if a mare is in winter anestrus, you could have the field she is in populated by multiple stallions, but she won't start cycling until the daylight has increased sufficiently in duration!
Even with mares that are apparently cycling in the winter, a good percentage of them will not be ovulating - and therefore, again, no matter how many stallions are around they aren't going to get pregnant. In this case however, as they are in anestrus, there is no progesterone circulating, and therefore they may not resist a stallinos advances, which could lead one to believe that they are in estrus (progesterone is the hormone that causes resistance to the stallion, and it is secreted by the CL which is what forms on the ovary following ovulation - hence with the winter anestrus mare, no ovulation > no CL > no progesterone > no resistance to the stallion).
And even when it comes to the regular breeding season, there is an intricate "dance of the hormones" that the mare must go through in the right order and for the correct duration in order to have an estrus. Again, simply introducing a stallion will not cause the mare to go into heat (this is actually one of the items covered in out "breeding mythinformation" article). If the mare does not have a stimulus (stallion) around and perhaps is already in estrus, then the sudden introduction of the stallion may cause the estrus display; or if the mare is submissive, then she may display estrus-like behaviour as a result of being exposed to the stallion, but this is not true estrus. In neither case is the stallion "bringing the mare into heat". In the first case she is already in - just not showing; in the second, she is not in estrus, merely submissive. That cascade of hormones has to happen in the right order to achieve estrus, and simply introducing a stallion won't cause it to happen - sadly! I wish it were that easy!!!
Posted on Wednesday, November 29, 2006 - 09:21 am:
I apologize for my above answer, but my info comes from past experience of a friend of mine. A gal I know here in MN also thought mares wouldnt ovulate in winter months, so she turned her stallion out in the herd with the young stock, geldings and unbred mares (he was super quiet, she only kept him seperate during breeding season). well long story short she ended up with multiple bred yearlings and mares she didnt want bred, all with mid winter foals. (end dec-early feb) These were all horses who were under no lights, pasture turn out only. So why would that be?
Posted on Wednesday, November 29, 2006 - 11:10 am:
My above post observes: "some mares may cycle year round and ovulate (and therefore be fertile)".
A minority - 15-25% of mares - may continue to cycle and some will ovulate. But it's not the stallion's presence that's causing them to cycle! They'd do it even if he weren't there, they just might not be as demonstrative.
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