I have a mare that is due to foal any day now. With her three previous foalings she has not seemed to cycle normally afterward.
We would usually start teasing her around day 25 post foaling. Her basic pattern is to tease for a day or two, then not, then tease for a day, and so on. When we checked her by palpation and ultrasound in years past, she would have a whole bunch of small follicles (10-12 mm). Occasionally she would have a 20+, but the next day or 2 days later, the larger follicles would be gone. My understanding is that this is what some mares do during transition? The vet never saw a CH or CL. I guess it is possible she had a CL from foal heat that was gone by this time, but we never teased her at that point as we weren't trying to breed her.
The first year, we weaned the foal and within 3 weeks she cycled "normally," with one follicle of appreciable size, and was bred back successfully. The second year, she did not return to heat after weaning. We gave 10 days of Regumate and then she cycled, again with one primary follicle, and was bred back. The third year Regumate didn't do the trick, so we tried P&E and that worked. Then she had the next year off.
This year, we would like to breed her back on foal heat (assuming no foaling issues that preclude foal heat breeding) or the next (if she would cycle...) as it is already late in the year.
What would be the best way to manage her for the best chances of a good ovulatory follicle and pregnancy?
I read about using not more than 3-5 days of P&E at foaling to delay foal heat ovulation, and thought that might be applicable. Or would a 10 day course of P&E later be better?
There is an article that discusses the merits and techniques behind delaying foal heat on the web site in the articles section that will probably answer a lot of your questions.
Some mares will have the foal heat, and then lapse into lactational anestrus. Some won't even have the foal heat; while others may appear to lapse into anestrus but are in fact cycling but having silent estrus. Really the only reliable way to identify what these mares are doing is with a combination of ultrasound and blood-progesterone assay.
There is a risk in deciding to use the 10 day P&E in that if the mare is truly going anestrus after the foal heat, then the P&E may not work. Without knowing what it is that your mare does, it is difficult to predict which is the better route to go, but if it were me, I think I would err on the side of caution and attempt to delay the foal heat.
When this mare has been given 10 day P&E in the past (3 or 4 times over the years), with .2 cc Lutelyse on day 10 and day 11, she is consistently late in responding. Meaning, she is ready to breed on day 21 or 22 instead of day 19 per "the book." You know, that book that mares have difficulty reading...
Is it reasonable to assume that she would be similarly late with a 5 day course of P&E? Would it be better to use 3 days in her case? Or, is there any harm in delaying foal heat ovulation to day 13, 15, or whatever? Or, is there a risk of her becoming anestral if the cycle is suppressed for too long?
Am I correct in reading that no Lutelyse is given after the short course of P&E in this case (that makes sense, since theoretically there has been no opportunity for ovulation, and thus no CL). Is there harm in giving Lute after the short course?
Are you considering her "ready to breed" based upon a pre-ovulatory follicle? Note that mares are not expected to ovulate until about day 21 of overall treatment period on P&E unless they receive hCG on day 18 in the presence of a 35mm follicle.
The use of P&E post-foaling is different from "timing" mares with it, and is used to prevent development of a pre-ovulatory follicle - you will not get the nice timing after cessation of treatment - and therefore ovulation prior to 10 days post-foaling (a magic window that increases likelihood of conception). I would therefore not have concerns about delaying the ovulation. There should not be an association with anestrus. Note that the average for unmanipulated post-foaling ovulations is anywhere between 5 and 15 days post-foaling.
You are correct in the supposition that as there is no CL there is no need for PGF2a although giving it probably won't hurt anything except making the mare a little uncomfortable, and it cold in fact be argued that it could even be beneficial in some cases for the ecbolic properties.
By "ready to breed," I meant the day after a 35 mm follicle is present and HCG can be given. While that is theoretically day 18 (with breeding on day 19) for most mares, it has been more like day 20 (breeding day 21) for her.
Just out of curiosity, is there any reason HCG would not be as effective on a foal heat?
Thanks so much. Now I feel like we are going into this "armed"
Thanks again Jos. I read elsewhere about your recent misadventures in the "sperm mobile" and hope you are well!
Well, the mare foaled. On the day of (6 hours after) foaling she got P&E, and P&E for 4 more days. On the last day of P&E she got .2 cc Lutelyse, then the day after another .2 cc.
If you count the day of foaling as day 1, today is day 10. We just had her ultrasounded tonight and she looks like she is doing the same thing as in years past.
She has a whole bunch of small follicles, with the largest being 25 mm. She does not have a CH or CL. So based on the other times that we have seen this kind of follicular development (or the lack thereof) with her, I suspect that she is not even going to have a real foal heat.
Should we figure she is not going to be impregnated this year, or is there something else we should try? A full course of P&E? Voodoo?
Do you have any knowledge or experience with luprostiol (http://www.fda.gov/cvm/FOI/1407.htm) that might indicate it could be beneficial in this instance? I just found this googling "lactational anestrus," so maybe it is not pertinent.
(Message edited by orsbreederz on August 07, 2006)
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