What you described sounds like a common response during estrus. Some mares won't show any difference throughout the year, while other mares are very demonstrative of the estrus. Some mares become very aggressive, exhibit a change in personality, have back pain, refuse to be ridden, etc. If for the first 16 years of her life, the mare did not show any sign of what you described, then it is recommended to contact your veterinarian. A veterinarian can palpate/ultrasound her and check for any abnormality in her ovaries. If it is simply the mare's personality, and you need to show or ride her even when she is in heat, it is recommended to talk to your veterinarian about putting her on Regumate or other options to manage the heat cycle pharmaceutically.

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