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  Discussion on Why isn't lutalyse working in this mare
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New Member:
Cspanhel

Posted on Wednesday, Sep 13, 2006 - 2:05 pm:

12 year old maiden mare bred on May 7 with positive preg checks up to day 51, but negative for pregnancy on day 103. She was re-preg checked by another vet on day 117. Same conclusion--not in foal. So, we have all reached the sad conclusion that the mare lost the pregnancy. All the preg checks used both palpation and ultrasound, and both vets are very experienced equine repro vets.

Now I'm trying to reculture her before rebreeding this fall, and the vets wants her in heat to culture. She has not shown heat since she was bred in May. I had her ultrasounded last Thursday (9/7), and she had a 39 mm follicle but closed cervix. She had closed cervix on Friday 9/8, so she was given a lutalyse shot that day and vet said we should be able to culture early this week.

Five days since the lutalyse, and still no sign of coming into heat, and I have my stallion here who she loves, and I've teased her twice a day since she had the lutalyse. The stallion shows little sexual interest in her after greeting her. She rebuffs him after greeting, then he just goes back to eating or whatever.

So, I have many questions as to why she is not responding to the lutalyse--she was given lutalyse this spring, and it 'worked.'

I'm wondering if a) it's harder to get her cycling after losing the pregnancy b) it's harder to get her cycling due to the time of year or even c) is she still pregnant? I can't imagine that the answer to c) is 'yes', but she does look pregnant, and even the 2nd vet thought she must be pregnant (on 9/1) from her looks prior to ultrasounding her and concluding that she wasn't.

I read on one of Dr. O's posts that between 90-180 days, it's possible to miss a pregnancy by palpation...but would the same be true for ultrasound?

cynthia
Moderator:
DrO

Posted on Thursday, Sep 14, 2006 - 9:56 am:

Hello Cynthia,
Yes horses do quit cycling following the loss of a pregnancy after a certain amount of time. This phenomena is explained at Diseases of Horses » Reproductive Diseases » Trouble Settling Mares & Stallion Infertility » Abnormal Heat Cycles (Estrus).

It is not so much that a pregnancy might be missed as it is that at this stage it requires more careful and knowledgeable palpation Cynthia. As to whether yours may have been misdiagnosed depends on what the findings were and how well they were interpreted. As to whether a mistake was made on your mare I cannot say but I would want to be 100% sure before giving Lutalyse to a mare that has been bred and is not cycling.
DrO
New Member:
Cspanhel

Posted on Thursday, Sep 14, 2006 - 2:41 pm:

Thank you Dr. O. After I posted, I found the article you mentioned and read it. As I said, both of the vets that ultrasounded/palpated her are very, very experienced repro vets, so I shouldn't doubt the result, but the fact is the mare is not cycling (still not today), and she looks heavier around the flanks, has some udder development...

so, my new question is how can i be 100% sure she is not pregnant...Would you recommend some other type of test? or just wait her out and see if she starts to cycle? THANKS.
Member:
Banthony

Posted on Thursday, Sep 14, 2006 - 3:42 pm:

Hi Cynthia,
We had a mare last year that we AI'd three times. I was sure she was pregnant - she looked pregnant, but alas she wasn't. She never showed heat again after the third breeding.

We wanted to do a uterine biopsy on her and gave her Prostin. She never showed in heat but upon palpation it was found that she was cycling and her cervix was open - allowing for the biopsy. But behavior-wise she never showed in normally until we put her under lights in January. She started cycling normally at the end of February.
Member:
Banthony

Posted on Thursday, Sep 14, 2006 - 3:43 pm:

Oops, sorry - we put her under lights in December. It takes 60 days or so under lights.
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