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  Discussion on GCT
Author Message
New Member:
meganv27

Posted on Saturday, Jan 2, 2010 - 10:05 pm:

Dear Dr. O,
In may (approx. 8 months ago) I bought an 8y/0 Oldenburg mare to show for the summer. She behaved very nicely at first, except for pinning her ears when initially placing her girth. She went to 4-5 shows during the summer and by August she was acting very aggressively. She would pin her ears and nash her teeth in her stall if you tried to take her out and also did the same when tacking her up. Also as the summer progressed she became very sensitive to being brushed on her left side. We tried an implant sub-Q in her neck, which helped through August and September but she became very aggressive again in the fall. She is difficult to catch from the pasture and will even go as far as hiding behind another mare. She continues to try and bite while tacking her up and pinning her ears while touching/brushing her. She will even try to bite or kick when getting her out of her stall. This has started to worry me since it is now winter and I would expect her to not be cycling currently. It has definitely been progressive in nature too. I am concerned about a GCT. She is a wonderful horse to ride and incredibly smart! I would love to figure out the root behind her behavior. What would your suggestions be? Is worth getting a workup done for GCT? Thank you for your time!
Moderator:
DrO

Posted on Sunday, Jan 3, 2010 - 10:26 am:

Welcome Megan,
Yes I think unexplained behavior, particularly aggressive in nature, deserves a GCT work up Diseases of Horses » Reproductive Diseases » Trouble Settling Mares & Stallion Infertility » Granulosa Cell Tumors in Mares. Even if a low percentage move, if found and corrected your problem is solved. Is there any aggression shown towards the other horses? What type implant was used? There may be a clue there also. Lastly once saddled how is the mare's behavior?

Another avenue to pursue would be to contact the previous owner/trainer explain the behavior and see if there is any history of prior problems and most important how did they deal with it. If this turns out to not be a medical problem this may give you clues as to how they maintained this horse to the state it was in when you bought it.
DrO
New Member:
meganv27

Posted on Sunday, Jan 3, 2010 - 12:26 pm:

Dr. O, Thank you very much for all your thoughts. To answer a few of your questions: She is very bossy out in the pasture and will bite or kick at some of the other mares. Often times too, if we try to bring her in before dinner time to ride, she will run away, pin her ears or try and bite.
I am not sure the hormone in the implant, but I can look into it. Normally once under saddle she acts fine, but over the past couple of months she has gotten more sensitive about asking for a canter transition and has kicked out a few times.
As far as having her worked up for GCT. Is it better to check certain hormones, specifically Inhibin, or will a testosterone or estrogen level be sufficient? Also is it a good idea to do ultrasound or rely on physical exam? I am just wondering what tests are better in being specific vs. sensitive? Thank you so much for your time! Take care,
Megan
Moderator:
DrO

Posted on Sunday, Jan 3, 2010 - 6:53 pm:

Hello Megan,
The details, including sensitivity and specificity, of the various diagnostic techniques are covered in the article. But as a general rule start with easier less expensive and work your way up the ladder.
DrO
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