I'm looking into this at the moment in order to decide whether to bother with it in my ET programme.
In the UK this is fairly new and it seems to be getting mixed reviews, so I thought it might be helpful to get some views from you guys where it's been used more widely.
Firstly it's an expensive protocol and relies on jabbing your mare quite a bit (not totally comfortable on the ethics of sticking needles in them frequently in order to 'maximise' production - but that's another topic). Secondly there seems to be some evidence that if a mare produces multiple ovums that they can 'compete' to get through the ovulatory fossa, which can result in no ovums actually being ovulated because they get in each others way.
I've heard reports of some people routinely getting 4-6 embryos from a flush where they've used EFSH, but to me I think this is the exception rather than the norm... would I be right in thinking that??
In you guys experience, do you really think it's worth the aggrevasion and expense? My mare has double ovulated on a couple occasions already, so she already has a head start. Would EFSH help a mare like this or not?
You can read more about eFSH, including some research that was performed at Colorado State University by going here.
You will note that the average number of ovulations appears to be in the region of 4. This is not the same as superovulating a cow which may result in as many as 20 or more embryos!
I have not heard of the situation you suggest with "competition" to get through the ovulation fossa, and would tend to be somewhat skeptical of such a likelihood. I am aware however of clinical research that suggests the if it is administered to mares that have a follicle >2cm at the time of the initial treatment, it may result in an ovary that looks like a bunch of grapes with lots of follicles, none of which ovulate! This is thought to be because of the inhibiting effect that a dominant follicle exerts on secondary follicles. It is recommended not to use eFSH in mares with follicles 2 cm or larger in diameter. Another clinical observation is that it does not appear to be as successful in producing multiple ovulations in older mares as it is in younger ones. Finally, be aware that it is likely that the ovulations may occur at a "staggered" time interval (this is why I am somewhat skeptical about your above observation), which is a problem as you could end up with embryos 2 or more day apart, and that presents some difficulties with successfully transfering them in some instances.
As I mentioned in previous posts, I brought my mare to CSU under the care of Dr. Patrick McCue and Dr. Logan. Here is Dr. McCue's protocol used for my mare:
The average interval from the last day of regumate therapy (mares get prostaglandins on the last day of regumate therapy as well) is about 9-10 days, without any hCG or deslorelin treatment. The donor mare would start eFSH therapy the day after regumate stops. It will take the donor mare 5-7 days of eFSH therapy, then perhaps one day of coasting (no treatment), then hCG and she gets bred. The donor should be lined up 1-2 days ahead of the recipients. For clarification, we typically flush on the afternoon of day 7 or the morning of day 8 postovulation. We flush on day 6.5 only if we are intending to freeze a small embryo.
Regards, Dr. Pat McCue
We followed this protocol for the second attempt at ET retrieval. In spite of the EFSH, and four nice follicles, no embryo was retrieved. Likewise, on the final cycle, NO EFSH was administered, four follicles developed nicely, yet no embryo was retrieved. The EFSH was not inexpensive, about $70 per day.
In hindsight, especially with a warmblood, I may not choose to use EFSH in the future. It seemed that with or without it, my mare had multiple ovulations, although no embryo was retrieved.
Posted on Wednesday, November 09, 2005 - 04:59 am:
My information about embryos 'competing' came directly from Twink Allen's team at the Equine Fertility Unit at Newmarket which is the leading authority on ET in the UK. May be they have experienced problems because when they used efsh the follicles were already >2cm ....
The mare in question will be 18 yrs old next year and is TB x Arab. As I said, she often double ovulates, so perhaps efsh is not the way to go with this mare bearing in mind what's been said about it being less effective in older mares...
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