What's wrong with my mare?!!!!!?

A cyst is a very possible idea.

Horses with HYPP, particularly those that are H/H (double positive for the gene) are known to tie up at horse shows. Though it would be really weird for a barrel horse to be halter bred like that. Does she seem to want to sit on her butt like a dog when tied to a trailer all day? If so, that's HYPP, and the spasms often seem to be like tying up.

A mare at my trainers has really horrible heats beyond normal witchiness. She gets a shot for it.

I would obviously talk to the vet, but I'd consider checking out a supplement for witchy mares from SmartPak. I have never used their mare supplement but I've used a lot of other products, and they are always excellent with 100% money back guarantee.

Get in contact with a vet, as this sounds like a serious health issue. Perhaps hormonal or nutrient deficiency, perhaps something else.

Yahoo! Answers unfortunately can't do much to help you out here. Your best option is to call a vet for a check up.

It could literally be anything. Maybe her hoof balance is off, maybe laminitis, navicular, needs chiropractic work, etc. I would have a vet take a look at her and go from there. It may be expensive, but it will be less expensive than treating her when you don't know the exact cause. Good luck!

The lameness in the front is nothing to do with her rabid heat cycle or her tying up. You should try to educate yourself about tying up. No starchy grain (NO CORN EVER). The most important thing with tying up is you need to keep walking her as soon as you come out of the ring. When you unsaddle her keep walking.......................do NOT STOP. You will have to walk her 20 to 30 minutes after a ride (especially at a show) Do Not stop to offer water or untack until about 10 or 15 minutes after you ride. Take the tack off at a walk about 10 or 15 minutes after a ride. Pay attention to the situation at hand and if she does not drink out of the bucket you have set up for her outside in the cooling area........keep moving. Do not stop to talk to friends after the ride. The key is to keep moving. Also, before the show it is a good idea to throw the saddle on her at home and walk her around the barn for 20 minutes or so. On her days off, you still need to go there and hand walk her for 20 to 30 minutes. Make sure she goes in a field with another horse for at least 8 to 15 hours every single day, come hell or high water. There are anti tying up serums to give the horse before it excerises. You really need to speak to your vet and come up with a game plan. If he is not an equine specialist find one who is. With proper management, feeding and vet prescriptions you can avoid this very, very painful performance hindering affliction. Research everything and anything and talk to an actual equine vet. Without vet assistance you wont be able to correct this.

Edit^^^Without proper management and vet care the horse will back off of training. No alfalfa or high sugar, stress management, Feed management, owner knowledge are the only ways to overcome this. Don't rely on YA Horsey...do a lot of research and confer with a horse vet, and then research some more. YA Horsey is mostly for beginners and you will only get a handful of some actual sound advice. Just keep walking...even when things seem good...walk, walk, and walk some more. Never stand before or after exhertion. Best of luck!

Edit 2 ^^^ If it were me, I would forget about running, altogether, at this point. You can pull this horse back together with more knowledge than $. It would be best to get a handle on the tying up more so than running, right now. It will pay off in the long run...because you can not win on this foundation. So...whats the point. I know you want whats best for your horse. It took one year and two months for a bad tying up filly we got to be able to successfully race. She finished second by a hair...for $35,000 and did not have any issues, afterward.

How about consulting a Vet. In heat that much is a free red flag, get her checked by a VET !