Jos, my brother and I are getting ready to rebreed 3 mares - Since the public has had such a fit in the past over live coverage where the stallions are stabled, we now meet in the middle at our vets, I bring the mares he brings the stallion. So we would like to have the girls in sync.
When preparing to have our prescription written for the P&E protocol you wrote about in your article in 2004, I researched BET Pharm's site and spoke with them about the single dose BioRelease Altrenogest LA 225mg cocomitant with PGF2 on the same day. They reported that this protocol would bring the mares into estrus within 12.3 days and ovulation at 16.9 days.
What is your experience with the BioRelease Altrenogest single shot vs. the daily P&E protocol?
Is the single shot BioRelease a more effective method to use with fresh semen AI covered mares? The single-shot is certainly less labor intensive.
If their timeline is correct and ovulation begins at 16.9 days, when would the appropriate time to administer the hCG Desorlin be?
I should note, my brother, Harold Parker took your course twice and thoroughly enjoyed it. He does beautiful work with our stallions, including live ground collection. Our vet is familiar with you and your work, but prefers to use Regumate, though he will assist us and use any protocol we choose based on our experience. We are breeding a special breed of horses that our great-grandfather started 100 years ago and we have been having great success. Thank you for helping us stay on top of the new science.
We have found that the Biorelease altrenogest works well but is not quite as accurate as the daily dose P&E (although is close). If one is using fresh or cooled semen and are following the mare, the Biorelease product is excellent in that one only needs to use a single injection (plus the Prostaglandin F2α).
We would recommend checking the mare at 14 days after giving the initial injection and then once a follicle >35 mm is present, use hCG or >30 mm use Deslorelin (note the difference for the different products). Ovulation will typically occur in the next 24-28 hours in those situations, so breeding with fresh semen the next day would be suitable. It is still worth checking for ovulation 2 days after breeding to confirm that the mare does not need to be need again, as nothing is absolute...!
Thank you for your help, Jos. I got the mares going on the Biorelease altrenogest protocol and now they are due for their Prostaglandin F2á shots. BET-Pharm sent me Cloprostenol 25mcg/ml. The bottle reads "Inject 1-4ml IM" and they say an average dose is 2 ml. BET-Pharm says that Cloprostenol is a kinder Prostaglandin and does not have the usual side-effects and that is why they use it. Based on your experience with Cloprostenol: Is 2 ml a safe dose for my mares (all 1300-1400lbs)? Should I still break it up in two doses (1 ml each) just to be safe?
I plan to have all 3 ultrasounded again on the 14th day, just in case anyone is in early estrus. Based on those ultrasounds, I will have them checked again at 16-18 days and move them to the vet hospital for breeding at that point, too. On their first ultrasounds, the vet said that he felt like he was looking at 3 uterus' on the same cycle. With any luck, with the intervention the mares are staying that way. Thank you again for your assistance. I will let you know how the mares do.
Cloprostenol is a synthetic analogue of Prostaglandin F2α and has a longer half-life, so a single dose of 25µg is adequate. If you were using native Prostaglandin F2α (e.g. "Lutalyse") then you would have to use 1/10th of the dose 2 days consecutively.
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