My mare was diagnosed with Lyme disease after 6 moths of being aggressive and breaking out of the pasture and trying to kill me and my dog. She has been on doxycyline for 1 week now. She had just started to show some improvement when she suddenly went after us again. This horse has never been like this. She has always been on her best behavior! She now (started yesterday) gotten very spooky. She was just spooky at an empty food dish yesterday, but today freaked out at her hay, food, blanket, toys, me, her stall and her treats. She is punished when she does something wrong, so no she is not getting away with any bad behavior. I have been working her with this spooky behavior. To note this mare has NEVER spooked at anything. She has always been "bombproof".