Tying Up

by Jerry H. Johnson, DVM, MS, Dipl. ACVS

I have a filly that mildly ties up on occasion. What is tying up, what causes it, and what can I do about it?

Most of the time we see tying up, or exertional rhabdomyolysis, in young horses, generally fillies. You can see it in colts and geldings, though. It seems to be related to how nervous the horse is, and related to the amount of carbohydrate intake.

Most frequently it happens when something is changed-the horse has had a day off, it's asked to do a little bit more than it's done in the past, or perhaps a change in the feed. Additionally, I think it could be related to moving to a different environment, changing tracks for example. But it could be most anything, like changing tack or changing riders.

As to why we see it more in fillies, they might be a little more nervous and that might instigate it. Frequently it is persistent, and when they get the idea that something is going to happen to them, such as tying up-and it is painful to them-then they will tense just getting to the racetrack. So it is beneficial to spend as much time as you can getting them to relax. Changing their training routine is sometimes helpful.

Helpful supplements that can be added to the feed would be vitamin E, which seems to be beneficial, and B1, which seems to settle them down. Giving lactinase supposedly helps eliminate the lactic acid build-up, which is what actually happens in a horse that ties up. Lactic acid builds up in the muscle cell.

I think a muscle has to be conditioned to receive nutrition and eliminate waste. The lactic acid is a by-product of the breakdown of the nutrients in the cells. If it's done too rapidly, as you see in a horse that ties up, then you get a build-up of lactic acid that's not being excreted. And that's why horses are conditioned like they are over a period of many months before they race.

One thing that we need to mention is looking at blood enzyme levels. They will be elevated, and that gives you a monitor as to how the horse is doing training-wise.

With a blood sample, you can measure the level of the LDH (lactic dehydrogenase) and SGOT (serum glutamic oxaloacetic transaminase). What you are measuring the cell by-product in the blood. You're measuring the lactic acid in the blood. The LDH will be the first one elevated, which is elevated immediately. The SGOT goes up secondarily, and it is the last one to drop back down to normal levels. That's when you know that the horse has responded or is a at stage that work can continue.

I've never seen one tie up on the way to the track, and rarely do you see one tie up after a work or a race. Most of the time it's a training routine that maybe the horse did a little bit more or got excited on the way to the track. And most of the time you can feel them starting to get a little bit tight and short-strided.

Tying up can appear as anything from a horse that's starting to walk just a little bit short in one or both back legs to one that's extremely bad or even down. Occasionally you see it just involve the front legs, but most of the time it's the back legs. They show signs of pain, sweating, eyes wide open, and nostrils flared.

All cases don't have to be treated. Some horses will walk out of it on the way back to the barn. The ones that get severe need to be treated for the pain and to help them eliminate the lactic acid build-up.

You see tying up in Thoroughbreds, Quarter Horses, Standardbreds, and you'll see it in some pleasure horses. It's the old "Monday Morning Sickness" that used to be referred to in draft horses. Their feed was not cut back on the weekend when they were off, then they would start back to work on Monday after they had been on full rations and tie up.

So it's always advisable for a horse that's prone to tying up to cut back on its feed on the days that it's not needing as much of the carbohydrates as it would normally be fed. I don't think nutrition is the total answer, but I think it plays a big part.

If the horse is tied up severely, it's probably best not to walk them. If it's just starting to walk just a little stiff, walk them fairly slowly and let them pick a little grass occasionally. If you keep them moving, some of those will walk out of it. But I wouldn't whip the horse to keep it moving. In that case, I think you're better off to just put them in a stall and give them something for relief. Then maybe walk them later that day.

If you have a horse that you can't stop them from tying up, then obviously it isn't going to be able to be a racehorse. Some that tie up-if it's not too severe-it's probably best to take them back to the track the next day. Sedate them before they go to keep them from getting quite so nervous. Change in routine can be beneficial. Changes that might "set the horse off" might be if the horse has only been going to the training track and jogging and galloping, then you take it to the main track and it sees these other horses breezing by. It gets nervous and upset and is not real sure what it should do.

Mild sedation seems to be best for a horse that ties up frequently. They can tie up for several days in succession. A little tranquilization before they go out seems to help them and let them mentally get adjusted to the fact that they are going to go out and it's not going to hurt. Some just get very rattled when they go from a training facility to a racetrack and see all the action that's around.

As far as it running in families, there very well could be some genetic tendencies, but to my knowledge we haven't been able to define that. I think that very well could go along family lines.

Jerry H. Johnson, DVM, MS, Dipl. ACVS, is a private practitioner at Thoroughbred racetracks in Central Kentucky and South Florida, and he is chairman of the Problems Analysis Committee of the American Association of Equine Practitioners.

Reprinted from The Horse: Your Guide to Equine Health Care