From www.wfaa.com ARGYLE Oct 11 -- A Denton County woman is begging a thief to give back her horse. The animal is special -- so special, that losing it is literally threatening the owner's health. "My husband always says I have more pictures of my horses than I do of my kids," and to Roberta "Bird" Gierhart, this horse was precious. Bobbie, her 17-year-old Arabian mare, was her pride and joy. Three weeks ago, someone stole the horse. Gierhart, 49, has Parkinson's disease. She learned that riding a horse is good for her muscles. "It really stretches them out, using your legs, your arms and you forget about the shaking... and all of a sudden, you relax," she explained. "I don't know what I'm going to do if I don't get her back real quick." Gierhart found that a lot of horses are spooked by her shaking -- but then she found Bobbie. Almost right away, the chestnut mare showed the movements didn't bother her, and the two became the best of pals. Last month, while trail riding, Gierhart fell out of the saddle. A frightened Bobbie bolted into some woods. The horse disappeared and police are sure she was stolen. "It's been horrible," Gierhart said tearfully. "I've had to get more medication, and I don't sleep more than 2 or 3 hours a night. "I worry about where she is, and if somebody's taking care of her." Gierhart has another horse, a stallion named Jazz, but her muscle tremors make him skittish. She says their friends and neighbors have been great, going out to search for hours. They're offering a reward, but so far, there hasn't been a trace of the sleek Arabian. Roberta Gierhart says she doesn't really care if the person who took Bobbie is prosecuted or not; she just wants her horse back... and she isn't giving up. "Just let her loose and call me on a pay phone," Gierhart pleaded. "Just tell me where you let her loose." Anyone who has any information about the missing horse should call Texas Crimestoppers toll-free at (888) 932-7263. Reporter: Bill Brown Copyright: 1999 by WFAA-TV Co. All Rights Reserved.