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  Discussion on Discontinuing Regumate....How and when
Author Message
Member:
judyhens

Posted on Tuesday, Sep 15, 2009 - 5:31 pm:

We had two 6 - 7 year old mares this year that were very difficult to get pregnant - despite high quality semen (2 different stallions), perfect timing (by ultrasound - before and confirming ovulation) and clean cultures. The others conceived - even ones whose reproductive hx. were iffy) and carried without problem. Finally in July the vet suggested we breed those two and start them immediately on Regumate. We did, they both conceived, and both were pregnant at 18 days. We left for Europe for a ~month in August, so just got them rechecked today. Both are still in foal and both remain on Regumate. The vet feels we can safely take them off. One is now ~65 days and one is ~55 days in foal. Good heartbeats and fetal size. Clearly, as late in the year as it is, we don't want to risk these pregnancies. On the other hand, we hate to use Regumate unnecessarily. I know that research is iffy re: efficacy. However, once started, how do we best stop it and when is the safest time to stop it? One of the mares is co-owned and that foal belongs to the other owner this year, so I will involve them in the decision. Just not sure if it should be continued a little longer, weaned off slowly, or stopped cold turkey. Any experience or thoughts would be appreciated. I did read the article on Regumate.
Thanks,
Judy
Member:
mrose

Posted on Tuesday, Sep 15, 2009 - 6:46 pm:

Hi Judy, we had an older mare who needed to be put on Regumate to retain her pregnancy and she had to say on it almost the entire pregnancy -  can't remember exactly, but I think it was at least up until the begining of her last "trimester."....up until just a month or two before foaling.  She retained her foal and foaled with no problems.  I do know we tapered her off gradually.  I haven't read Dr.O's article so don't know what his recommendation is; our mare was before I'd heard of HA.
Member:
dsibley

Posted on Wednesday, Sep 16, 2009 - 6:52 am:

Did the vet pull blood to test progesterone level? I would think this is the most definitive way to tell if the mare still needs it. It's too risky to just 'think'. I want to know for sure.
Moderator:
DrO

Posted on Wednesday, Sep 16, 2009 - 9:46 am:

I would note that fertility rates rise during the summer compared with spring breedings Judy and that you should expect a percentage of healthy mares to not settle and need rebreeding. I bring this up to emphasize a correction to your assessment of the research on progesterone and embryonic loss. It is not that the research supporting the use of Regumate is iffy Judy, the research is quite clear and has not changed in the past 25 years: if low endogenous progesterone in otherwise healthy mares is a cause of embryonic death, it is a rare event and no level of endogenous progesterone (other than zero in ovarectomized mares) has been associated with a increased incidence of ED.

This strongly suggests that Regumate was not a factor in maintaining the pregnancies. But you have probably read our article on this along with the research findings presented and considering your history not likely to pay much attention to this.

We know that progesterones from the CL is needed up until about day 90 of the pregnancy and you frequently see the recommendation that it be used until day 100 to 120. I remain uncertain what effect discontinuing the Regumate in the middle of this period is. As a result when a mare is brought to me on Regumate I continue the treatment until day 100 and tend to wean them off it over the next 20 days.
DrO
Member:
judyhens

Posted on Wednesday, Sep 16, 2009 - 3:51 pm:

Thanks for everyone's input. After reading your posts, we decided to continue it for awhile. If we stop it now and anything happens to the pregnancies we will always wonder if stopping Regumate caused the problem, whether it did or not. So...we will probably continue until day 100 and wean off as described above. Once you start it seems you are sort of in a quandry.

In central Texas, where we live, the pregnancy rate across the board (according to our repro specialists and other area vets) was already DrOpping significantly by July. They attributed it to the intense heat - 3 digits without relief for many, many days. Actually broke a record for heat since 1925. This is apparently unusual. But it may have contributed to our problem getting these two mares pregnant. In addition to Regumate, we added fans and cool shelter for these 2 mares. Some owner's own vets recommended waiting until later in the fall when it was cooler to try again. Very unusual summer!

Again, your input is appreciated!

Judy
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