Exercise-induced muscular cramping and spasm (a.k.a. tying-up) remains a significant problem for many horses. Since our in-depth story in April and May 1998, several products have appeared that address this syndrome by manipulating mineral levels and acid-base balance (pH). It may surprise you to learn that a key ingredient in all of them is magnesium.
The horses in our trial had a history of obvious tying-up or problems with tight/tense and painful muscles after exercise (possibly low-grade tying-up). Horses were evaluated by our veterinarian for resting muscle tone, spasm/fasiculations (fine spontaneous twitches) on palpation and percussion (tapping) of the muscles and freedom of movement.
All had somewhat stilted gaits behind, shortened forward stride and behavior manifestations of pain including ear pinning, resistance to aids and picky appetites.
All had some degree of inducible spasm and/or fasiculations in some muscle groups, most common being the triceps (triangular shaped muscle above the elbow), gluteals (top of the rump) and quadriceps (controlling the stifles). Obvious pain responses and avoidance of touch were also common for the hamstrings (parallel muscle groups in the back of the hindlegs) and the pectorals (chest). Two horses had a history of tying-up, while the others had developed the muscular problems as their training had increased in intensity.
Major joint problems were not present. None had their training interrupted, but it was obvious to the trainers they were dealing with a muscle problem that needed attention. All horses continued in their regular exercise program while on the supplements. Supplements were mixed into the feed and fed on a once a day basis, usually in the morning. When morning feeding was not convenient and evening feeding was used, no difference was observed in the results. To confirm this, two horses in the morning feeding group were switched to evening feeds with no change in response. No other therapies were used, and no changes made in warm-up or cooling out procedures were made during the trial.
The ingredients list for Tie Free reads like a who’s who in muscle nutrients. Response to this product was excellent, including in two horses that did not respond to other products. Of the six horses given Tie Free, all showed a return to normal muscle tone, elimination of muscle pain and greatly improved gait within two to four days of starting the supplement. Because they were symptomatic at the start of the supplement, the higher pre-competition dose was used for the first day, then dropped to the maintenance dose. One horse showed some return of symptoms after high speed works, but we found we could prevent this by using a double dose the day before these harder workouts.
The manufacturer and label clearly caution against overdosing with Tie Free. These ingredients have profound effects on muscular activity, acid-base balance and hydration. We found that double dosing for even two to three days causes extremely relaxed muscle tone and some degree of weakness.
Although this product is an excellent choice for rapid control of muscular pain and spasm problems, it should not be used indefinitely without careful attention to intake of all electrolytes, especially sodium.
You may also be able to correct the tendency to have this problem by a careful dietary analysis of calcium and magnesium levels plus the use of an electrolyte mix to replace sweat losses and measures to guarantee required daily intake of salt (sodium chloride) — one to two ounces per day, regardless of horse’s work level and temperature.
Vita-Royal’s Untie also supplies all the key minerals important to muscle, as well as vitamin E, selenium and antioxidant trace minerals for enhanced damage control. This is the only product we have seen that uses amino-acid-chelated forms of all the major minerals and trace minerals, guaranteeing efficient absorption. Five horses were treated with Untie, four showing an excellent response, equivalent to that obtained with Tie Free, although it took a little longer (four to seven days).
One filly, who had spasm and fasiculations since she started training, was magnesium sensitive. Her basic diet started out at a Ca:Mg ratio of 3.22:1. Adding 5 oz. of Untie brought her to 2.45:1 and she was improved but still had fasiculations. She would stand in her stall and twitch after exercise. The local water was known to be high in calcium as well. Adding additional magnesium only (Magnesium 3000) to bring her total intake to 2:1 resolved the problem.
Adding to her high magnesium requirements was the fact that her total calcium intake of over 60 grams per day (when supplemented with Untie; 52.9 when not supplemented) was well above her estimated requirement of 32.7 grams. Active absorption of magnesium may be virtually shut down at this high-calcium intake, and more is lost in the urine on high-calcium diets.
Interestingly, a mare who responded well to Untie alone when housed at another barn developed symptoms again when moved to the location with the high calcium in the water, despite no change in diet otherwise. She, too, responded to adding more magnesium to her Untie. A more logical solution, however, is to get to the root of the dietary imbalances and correct them, then choose an appropriate supplement.
This is a useful supplement for horses with muscle problems who are known to specifically need magnesium. The combination eliminates the need for an E-Se supplement or can be used as an additional supply for hard-working horses. Horses that develop problems after coming off pasture and being fed hay, or when pasture becomes scant and hay intake increases, typically have a lower total magnesium intake and higher Ca:Mg ratio than horses on grass and can be helped by specifically boosting their magnesium. We have seen horses who have no change in their basic diet but develop magnesium-responsive muscle problems when moved to a barn with a different water source.
Horses that fit this description and were calculated to have a higher than ideal Ca:Mg in their diet responded well to E-Se-Mag, usually within three days. The horse with the most severe symptoms had a partial response but did not clear completely until switched to Tie Free. After two weeks on Tie Free, he was able to be switched back to E-Se-Mag and remained normal.
The indications for using Magnesium 3000, and horses most likely to respond, are the same as for E-Se-Mag. This is also a useful product, compatible with many other supplements when magnesium is the root cause of the muscular problem. It can be used instead of E-Se-Mag when your dietary levels of vitamin E and selenium are already adequate. We also found it useful as a complement to Untie when additional magnesium is needed.
Choosing And Using Supplements
If you use one of these supplements and find it effective, you know you are dealing with a mineral inadequacy. The major cause of this is an unbalanced diet, but the rising level of pollution in the form of organic acids also places an increased demand for these key minerals. Add exercise to the mix and it’s no surprise that problems occur.
Start with a complete ration analysis, including your hay, pasture and grain mix. Add to this the amount of any mineral supplements you are feeding, and don’t forget to consider your water.
Avoid excesses as well as deficiencies. Excesses can lead to decreased absorption and/or increased excretion of minerals other than the one in excess.
Your target dietary mineral composition for a 1,000-pound horse, in moderate work, prone to muscular problems would be:
• Calcium: 33-40 g/day.
• Phosphorus: 22-25 g/day.
• Magnesium: Half the calcium intake.
• Copper: 155 mg/day.
• Zinc: 460 mg/day.
• Manganese: Same as zinc.
• Selenium: At least 3 mg/day.
We would use Tie Free first to get control of the problem and maintain the horse while a dietary analysis is being done. We would then choose the product that most closely suits our needs.
Careful attention to electrolyte intake is also important. Be sure your horse eats the 1 to 2 oz. of plain salt all horses need and use an electrolyte replacement product in addition to this when sweat losses occur (see electrolytes August 1999).
While no product is going to work on every horse with muscular pain or tying-up, we found Tie Free to give the quickest and most predictable relief of symptoms. While horses have been successfully maintained long term on this product with no problems — and we wouldn’t hesitate to do so with a horse that would not respond otherwise — we would prefer not to feed high levels of potassium or bicarbonate on a regular basis if it can be avoided.
Untie also produced excellent results, although it took a little longer. It has the advantage of being compatible with your electrolyte mix (no added postassium or bicarbonate) and supplies some additional salt.
We would use Magnesium 3000 or E-Se-Mag for horses with an isolated magnesium deficiency but adequate trace minerals and calcium or use Untie for horses whose calcium level is borderline and trace minerals, vitamin E and selenium are not being supplemented (which applies to most horses that are being fed a grass hay-based diet).