I have a mare that is 45 days in foal. She finally conceived to an older stallion after she was put on Regumate right after insemination. My question is this, does she need to stay on the Regumate? They never tested the mares progesterone levles, just added the Regumate as a helper. Can I check her levels or will the outside supplementation effect the results? This mare is 13 and caught last year on the first try AI. No history of problems.
ELizabeth Hardy (22.214.171.124)
Posted on Thursday, November 14, 2002 - 09:56 am:
Jos had a very good repsonse to this question under the topic of Hormone Manipulation
I have copied it here for your reference:
Sunday, July 16, 2000 - 07:03 am -------------------------------------------------------------------------------- Hi Linda:
Initial Progesterone levels in the pregnant mare are supplied by the primary and secondary CL's. The secondary CL's come into play after about day 35 post-ovulation, when the endometrial cups are formed, which secrete PMSG, which stimulates the creation of the seconday CL's.
Around day 80, the placenta itself starts to produce Progesterone, and natural levels are at their highest between roughly days 56 and 160, but the peak level is at about day 120, and after that, levels start to decline. This is why the magical day of 120 is chosen to wean off Regumate.
There are several options open when using Regumate to assist in pregnancy maintenance (something which it has not been scientifically proven to do!).
Firstly, use it from day 3 post-ovulation until pregnancy is confirmed around day 16 by ultrasound. Progesterone levels should then be checked, and if less than 4 ng/ml, the Regumate continued. If greater, then the option to stop use is available.
The second option is to keep the mare on Regumate until about day 40, at which point once again, check the Progesterone levels and make your decision.
Thirdly, as with you, wean off at about day 120, when the natural level would be starting to decline anyway.
Fourthly, continue Regumate use through to day 300 of pregnancy. This method tends to be used only in habitual late-term abortion mares.
Hope this helps.
ELizabeth Hardy (126.96.36.199)
Posted on Thursday, November 14, 2002 - 10:01 am:
One additional comment in regards to Progesterone testing... the regumate will not affect the results .. the progesterone blood level test only shows the blood levels of progesterone actually produced by the mare
I have a mare that we used regumate on that we put her on it 5 days post breeding and then tested her levels around day 45 they were fine at that point so we took her off. I have a beautiful 2 year old filly as the result :-) I plan to breed mom again this next year.
Here to learn
Posted on Friday, May 02, 2003 - 11:00 am:
We tried breeded my mare four times last year with no success. This year we have waited for a not so early foal. Her heat cycles seem to be all screwed up this year. She does have a mild infection in which the vet wishes to treat the next time she comes into heat. The vet has told me his new plan is to give her a shot of regumate three days prior to bringing her into heat artificially. Of course I may not have that exactly right or may not have understood exactly what he was talking about but I thought that regumate was something you used for a while not just a shot here or there. Any suggestions?
Posted on Friday, May 02, 2003 - 01:08 pm:
I gave my foaling TB mare Regumate beginning the day she foaled for 8 days and then gave her Lutalyse on the 8th day. I dosed her w 10 cc. daily after making sure she had nothing in her mouth. On day 10 she was 'hot' in heat and when the vet checked her on day 11, she had a 4+ follicle. I have read that Lutalyse takes 3.5 days on average to bring a mare into heat. This leads me to believe that the Regumate/Lutalyse program didn't delay her foal heat. So my question is do you think this program didn't work on this particular mare and if so, any opinions on why not?
Posted on Saturday, May 03, 2003 - 02:40 pm:
Here to learn:
Regumate is not used in this manner. It is an oral preparation given typically for 10 or 15 days. Prostaglandin ("Prostin" or "Lutalyse" are common brand names) is however used like that.
What was the cytology smear showing on your mares uterine swab? Was one done? It is essential that this diagnostic test is performed in conjunction with a uterine swab culture. "Click" here for more information. Do not be sideblinded by your vet into believing that it is not necessary to perform this test. It is!
Posted on Saturday, May 03, 2003 - 02:52 pm:
Prostaglandin ("Lutalyse") is not used in this manner. Prostaglandins work by destroying the CL that is present on the mare's ovary, resulting in a drop in the circulating progesterone levels which allows the mare to come into heat by permitting the hormonal cascade associated with that to be initiated. Giving prostaglandin to a mare to do this is merely moving a natural occurrence to a different time slot in her cycle.
The post foaling mare does not have a CL present, as that structure is what is produced in the space left behind by an ovulated follicle. Hence, using prostaglandin in the manner you did would not work as the mare has not had a previous ovulation in the last 15 days (being pregnant).
The Regumate use may delay foal heat to some extent if started on the day of foaling such as you did. It would seem likely that this mare, had she been left to her own devices would have ovulated considerably sooner than the day 11/12 that she probably did.
Posted on Tuesday, May 06, 2003 - 12:42 am:
As you say, here to learn. I read about the 8 day "program" somewhere on the net, I'll have to find it again to see if it came from a reputable source and/or I followed their 'recipe' correctly. Your explanation re the CL certainally makes sense.
About the smear, I asked my vet if the mare needed to be cultured and he said not, that post foaling mares do not have 'clean' (I don't remember his exact wording) cultures that early in the game and it is more important to check how well the uterus has recovered, such as tone and lack of fluid (again not his exact words). Is this at least in part the truth, generally, would a foal heat mare have a worse culture/cytology result than, say, a mare that is short cycled or even let go to the next heat?
Posted on Tuesday, May 06, 2003 - 02:20 pm:
A post foaling mare will show large numbers of inflammatory cells on a cytology smear - the uterus has just undegone a major inflammatory response! Additionally, the post-foaling uterus is almost certainly going to contain pathogens that gained access during foaling. Consequently performing a culture and cytology on a post-foaling mare during the foal heat is worthless as far as beneficial diagnostics are concerned. On the second or third heat after foaling, it becomes valuable.
Posted on Wednesday, May 07, 2003 - 11:20 pm:
Thank you for the info, Jos, good to know.
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