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  Discussion on HCG affecting cycles?
Author Message
Member:
Mmmules

Posted on Tuesday, May 25, 2004 - 12:44 pm:

Sorry for the long post, but need to give some background.

I have a 10-year old mare that has had 2 foals-first year covered once on 2 cycles; second year covered once and took (she wouldn't show to the stud so was palpated prior to breeding). She had her last foal 1 year ago.

This year trying to breed her AI with fresh cooled semen. Culture and cytology were
negative.

First week of April, mare had a 35mm on Sunday and was inseminated with a 44mm follicle on Wednesday (oxytocin 4 hours post breeding). Vet rechecked next day and the mare had not yet ovulated, so gave 2nd dose of semen and oxytocin 4 hours post insemination. Vet said the follicle was soft and ready to ovulate. He did not recommend rechecking.

Ultrasound on Day 15 showed no pregnancy with a 29mm and several small follicles developing. Mare was rechecked Sunday with a 35mm follicle, inseminated on Tuesday at 42mm and given HCG, then oxytocin 4 hours postbreeding (Based on this mares previous cycle, I thought the vet should have waited 2 more days to order semen, but I was out of town). Vet checked her next morning and she hadn't ovulated yet, but sent her home as bred.

Day 16 ultrasound, no pregnancy and a 45mm follicle. Mare showed no heat to usual teaser. Teased very mildly 2 and 3 days later, had vet recheck and large follicle had regressed and other ovary had a 31mm. Two days later had a 35mm, but no signs of heat. Rechecked 3 days later and no follicular development. Vet said to tease until she comes back in naturally.

So here are my questions (finally):

What is your interpretation of what might be going on and do you have any recommendations? Could the HCG have affected her cycles (she was a 21 day mare, but that 45mm follicle would have been 5 days early)? I haven't read anything that indicates a problem and it was her first time getting HCG.

Thanks,


Moderator:
DrO

Posted on Wednesday, May 26, 2004 - 9:13 am:

Though you thought he should have waited to order semen you would have been really teed off if he miss the ovulation, I too order when the mare reaches 35mm no matter what the past history. No matter how expensive shipments are they are cheaper than missing a ovulation. On the other hand the vet should have checked for ovulation before stopping breeding.

Concerning her continued lack of estral behavior:
1) She is either pregnant, slow coming back to heat, has a persistant corpu luteum, or cycled without any behavorial estrus.
2) The HCG is not likely to have created any problems.
For more on this problem and possible resolutions see Equine Diseases » Reproductive Diseases » Trouble Settling Mares & Stallion Infertility » Abnormal Heat Cycles (Estrus) but take care do not do anything until you are absolutely confident she is not pregnant.
DrO
Member:
Mmmules

Posted on Wednesday, May 26, 2004 - 11:30 am:

Thank you, Dr. You are so right, I would have been bummed had we missed ovulation.

I hadn't seen the reproduction articles under Equine Diseases, so that is helpful. I am secretly hoping that she is pregnant, but my vet is sure she is not.

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