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Discussion on Using Deslorelin and HCG in same cycle
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Member:
indigo
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Posted on Tuesday, May 26, 2009 - 2:44 pm:
Mare had a 35mm follicle on Friday, vet gave HCG, we ordered semen for Saturday delivery. Mare had a 4.1mm follicle at time of insemination on Saturday at noon. Sunday morning she was re-checked and had a 4.2 mm follicle that was softening and also had a ring. Inseminated mare with second dose of semen and gave Deslorelin.
Question-- what effect with the deslorelin have after giving hcg the day before? I've never had a vet give one right after the other like this, so am curious what the reason would be. My vet said that in her experience the hcg takes 48 hours to induce ovulation, whereas the deslorelin generally only takes 24 hours.
Thanks!
CC
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Moderator:
DrO
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Posted on Wednesday, May 27, 2009 - 9:17 am:
Hello CC,
There is no work I am aware of that shows what happens when given together. They both have the same LH actions, through the same receptor mechanisms, so I would not expect them to conflict with each other. I have not heard that deslorelin reliable causes ovulation within 24 hours and believe it is similar to hcg: typical ovulation of a mature follicle occurs in 36 to 48 hours. I would be interested in any information to the contrary.
DrO
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Member:
indigo
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Posted on Wednesday, May 27, 2009 - 10:32 am:
Hi DrO,
I think this has just been her experience, not based on any hard research/evidence.
CC
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Member:
indigo
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Posted on Wednesday, May 27, 2009 - 10:32 am:
Hi DrO,
I think this has just been her experience, not based on any hard research/evidence.
CC
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Member:
ekaufman
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Posted on Thursday, May 28, 2009 - 8:54 am:
I've heard 24hrs for deslorelin as well, with a follicle at or greater than 35mm. But at that size, kool-aid might also have a high correlation to next-day ovulation!
Here's some more voodoo to confuse things CC. I think it's all in the vet. Some vets just rock at mare-side repro.. I've asked mine to save me the farm call and just throw the stuff over the fence in the general direction of the intended mare-- her success rate at my ranch is so high that I don't think she actually needs to bother with the actual glove and all that. If your vet has a good track record, do any weird thing. If not, find one that does! Just my experience, obviously, and my mares are doing their part as well.
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Moderator:
DrO
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Posted on Thursday, May 28, 2009 - 8:28 pm:
I went and checked several large studies of deslorelin and all used the approximately 36 hour figure. This was a recent summary of a large number of findings:
Theriogenology. 2008 Aug;70(3):445-7.
Induction of estrus and ovulation: why some mares respond and others do not.
Samper JC.
JCS Veterinary Reproductive Services Ltd., 2943 216 St Langley, British Columbia, Canada. jsamper@telus.net
The two most common procedures for breeding management of mares involve induction of luteolysis and induction of ovulation. Although both of these events are usually achieved, physiologic conditions affect the timing of the response. In a diestrus mare treated with prostaglandin F(2alpha) (PGF), or a PGF analogue, it is well documented that, on average, the interval from treatment to the onset of estrus is 3-4 days, whereas ovulation occurs 8-10 days after treatment. However, the diameter of the ovulatory follicle, as well as its status at the time of PGF treatment, determines the intervals from treatment to onset of estrus and to ovulation; these intervals can range from 48h to 12 days. Ovulation is routinely induced with human chorionic gonadotropin (hCG), recombinant LH (rH), or the GnRH analogue Deslorelin. On average, ovulation occurs approximately 36h after treatment, but the effectiveness of any of these treatments can be affected by the stage of the estrus cycle, follicle size and maturity.
I admit to little experience with desorelin I still prefer the older HCG regimen do to it's dependability and lower cost. As to ovulation following 35mm, on average follicles grow at 3mm a day and ovulate at 43mm so without treatment the average would be about 72 hours but so variable among individuals as to be useless as a method of timing insemination. These ovulatory agents greatly increases you ability to accurately predict ovulation for shipped semen.
DrO
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Member:
indigo
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Posted on Thursday, May 28, 2009 - 9:50 pm:
Thanks for the follow up, Dr. O. Sounds like following up the hcg with deslorelin was probably unnecessary but not harmful.
Oh well, if the mare checks in foal I'll be happy no matter what. ;-)
Thanks again!
CC
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Member:
mrose
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Posted on Saturday, May 30, 2009 - 2:13 pm:
Hi CC; I was just going to echo elk's thoughts. Having bred for a lot of years, I learned that if you have a good repro doc, just do whatever he says and it will work!  We always used HCG, but I know times change and we haven't bred for several years.
If you're doing AI or using frozen semen it especially pays to have someone that "knows the ropes" even if you have to travel a ways to a different clinic.
elk,
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