Progesterone injections vs Regumate oral; opinions??

[Faiths CremelloWB]

I have an older mare who I would just love to get one more foal out of. She is a Thoroughbred mare from the *Twist* line. She was bred in 07 and had a fabulous/fantastic 08 colt. She was bred in 08 and absorbed/lost it over the fall/winter. Bred this year and caught first try.

I have her pregnant now and all looks well. Though vet said she does not feel as tight as she should. He recommends regumate and then also suggested that progesterone injections may be easier as I would only have to do it M,W,F. And regumate is everyday. He says if I *really* want a foal by her {and I do!} then she would be best to stay on it for the term of her pregnancy.

Would love thoughts on the two products and which you prefer.

[Laurierace]

Not an answer to your question but I was told I only have to give the progesterone shots to my mare once a week. I wonder what the difference is? I think your mare is going to be pretty sorry to see you coming by about 300 days after three times per week injections. Once a week is bad enough.

[YankeeLawyer]

I don't know about the shots but I can say that regumate is easy, easy to administer as it is colorless, tasteless, and odorless and you can just put it on their feed as top dressing.

[Sunnydays]

I'm with the oral regumate. As long as the mare gets feed or supplements at the same time daily, you need only top-dress with the regumate, as yankeelawyer said.
Question:
How does one decide how long to leave the mare on regumate? Why 45-50 for some, 150 for others, 300 for some? What is the decision factor?

[avezan]

The first year I used regumate with an older mare, I was either pregnant or breastfeeding, I can't remember which. So I gave weekly progesterone shots so I wouldn't be handling it daily. The next year, my vet recommended the daily regumate, but I really wanted to do the injections again. She explained that with the injections, the concentration in the horse is not consistent. It goes up high, then gradually tapers off until you need to give another shot. With the oral regumate, as long as you give it daily at the same time each day, the concentration in the body stays very consistent, which is obviously preferred. I also thought that my vet was being overly precautious, not to mention selling me a very expensive drug for a long period of time!! (I actually dont' use this vet anymore) So we tested her progesterone levels and backed her off of it eventually. Good luck. I hope your mare holds the pregnancy. The cost of the regumate IS cheap compared to the cost of losing a year and rebreeding, but I think it is also overused.

[Hiddenacresmi]

I also have a mare that with every pregnancy has needed a little assistance with Regumare. We keep her on it for 120 days and then have taken a blood sample to check the levels. She usually is then done. I have been told that once the foal starts growing, it helps along with the required progesterone. Our vets have always recommended the oral Regumate.

[TrotTrotPumpkn]

I'm with the oral regumate. As long as the mare gets feed or supplements at the same time daily, you need only top-dress with the regumate, as yankeelawyer said.
Question:
How does one decide how long to leave the mare on regumate? Why 45-50 for some, 150 for others, 300 for some? What is the decision factor?

I was told it depends when the mare starts producing the requisite amount of hormone on their own. In otherwords you have to test for it. She also mentioned 120 not 150 as a typical date though...

[GracefulHano]

I'm going to try the injections this year on one mare. Sort of a last effort type of thing. The oral regumate is too difficult to handle. She won't touch it on her feed, and good luck giving it to her orally every single day.
One a week injection sounds easier for me and the mare. I'll give it a go!

[IronwoodFarm]

Oral regumate can be hugely problematic if it comes in contact with your skin. You need to be very careful and should wear thick rubber gloves when handling (the regular latex won't do). I don't like the risk associated with handling Regumate and use it only when necessary.

I've been fortunate that the mares who need progesterone have a level that is high enough for P4 injections. I have only had to inject them once a week, which is lots easier/safer than dealing with Regumate.

I also agree that in most cases it is not needed past 4 months as the CL should be producing enough hormones. However, it is not going to hurt anything to give the injections for the term of the pregnancy. Of course it will cost extra money for those 7 months, but if you really want a foal, it's not a bad idea. My experience is ancedotal, but when I have kept my "hormone deficient" mares on P4 through their pregnancy, I always had a full term foal delivered. When I stopped it after 4 months, I've had slips. So with those particular mares, if I am breeding them, I use P4 all the time, no exceptions.

[Equine Reproduction]

There are a huge number of errors and myths being perpetuated in this thread, in particular about endogenous sources of progestins, and when and where they occur, so rather than go through them one-by-one, for those that are interested, please visit the article on our site about Regumate use (http://www.equine-reproduction.com/articles/Regumate.shtml).

As far as P4 vs. Regumate vs. other exogenous progestins:

P4-LA (BET Pharmacy) has been demonstrated by Vanderwall et. al. to maintain elevated progesterone levels for a minimum of 7 days.

BET Pharmacy also make a long-acting altrenogest (a synthetic progestin) that is injectable and comes in a 12 day and a 30 day formulation.

Regumate is the only progestin that is FDA-approved for use in horses in the USA. Other progestins are either off-label use or compounded formulations.

Hope this helps.

[Joshua's Mom]

Kathy, Which one do you use, and why? I use the daily because that is what I have always used, and it does a good job for me. The 30 day would seem to be the easiest, the 10 day, OK , if the cost is about the same and the dose is not too large. What about when you use it to keep a performance mare from showing signs of heat? A friend that lives in the middle of nowhere uses the 10 day for breeding instead of P&E What are your thoughts on that?


www.windyridgefarm.com

[Equine Reproduction]

Kathy, Which one do you use, and why?

Except in very rare - and specifically required cases - we don't use progestins post breeding. The only time we will use them is to deal with a situation such as a mare with a torn cervix, or one that is demonstrating an attempt to go EED (uterine edema present at ~14 days, and poor conceptus characteristics). To illustrate how little we regard the "need" for progestin therapy to "support" pregnancy, we reviewed some statistics of our breeding season a few years ago. That particular year, between the two of us (Jos and I) we had bred 40 mares in their 20's. The conception rate in this group was 80% (32/40) - well above the "average" for all mares worldwide (which is around 60%). Of these mares, 3 lost their pregnancies at some point prior to foaling - a not unusual situation or statistic. The interesting thing is though that of these 40 older mares only one received progestin supplementation and that was because she had a cervix damaged from a prior foaling - and incidentally, she was one of the ones that lost the pregnancy! Although these mares did not receive progestin supplementation every single one went through the oxytocin protocol (http://www.equine-reproduction.com/articles/oxytocin.htm)!

It is in our opinion preferable to use altrenogest in the post-breeding mare if required, rather than P4 (progesterone) as with altrenogest, one can run a blood assay series (3 or more) to determine if the mare's endogenous progesterone production is adequate, whereas if one is supplementing with P4, that is going to affect the result (as the supplemental progesterone will assay). It is important to note that (according to McKinnon et. al.) about 10% of mares put on progestin supplementation post-breeding then fail to produce their own progesterone (or adequate amounts) as a result. In other words, arbitrary supplementation post-breeding with a progestin "just because" can result in the creation of exactly the situation that the mare was allegedly being "treated" for in the first place!

A friend that lives in the middle of nowhere uses the 10 day for breeding instead of P&E What are your thoughts on that?

In answer to your primary question, and the above portion, if we are using progestins for some reason, as long as we are not requiring a short-term effect (in which case daily Regumate is used) we prefer the Biorelease altrenogest from BET Pharm - typically in the 12 day formulation (note 12, not 10 day), although if we are using it to allow the use of an ovariectomized mare as a recipient mare for ET, then after the initial 12-day dose (allowing us to confirm pregnancy maintenance) we will switch to the 30-day treatment.

For synchronizing mares for ET or in the situation your friend is in, we have had good success using the biorelease altrenogest, and it is certainly preferable to give the single injection rather than the daily injections required with the daily P&E.

Hope this helps.