The Trademarked product "Endura-Lyte" is manufactured for Life Science Products in St. Joseph, MO by an un-named producer. There are several distributors available including Roger Rittenhouse, Teddy Lancaster, Safe Haven Specialties, A.B.C. and others. Jeannie Waldron`s article is entitled "Electrolytes and the Competitive Trail Horse".
This formulation contains NO bicarbonates. The milliequivalents of selected cations necessary for electrolyte balance in the working equine includes Na @ 4968mg/oz, K @ 2652mg/oz, Ca @ 752mg/oz, Cl @ 9940mg/oz and Mg @ 600mg/oz.
Supplementing with Endura-Lyte at 6 doses, 1.5 oz/dose, during a 50 mile race will replace 49% Na, 38% K, 48% Cl, 100% Ca and 26% Mg. 100% replacement is unnecessary since hay, grain and other forage will make up a significant amount of the total required.
How the cations are available makes a significant difference in the bio-availability of each cation, e.g. Ca acetate is much more soluble than Ca phosphate (also Mg in a citrate is more soluble than a calcite--"dolomite"). These ions need to be highly soluble to work at all.
Make sure you read your labels and understand what the ingredients are. Avoid products like Stress Dex that are high in sugars.
Buckeye Feeds has produced an excellent product called "Perform `N Win" with outstanding solubility and bio-availability. This product appears to be "less harsh" and prompts an almost immediate drinking response. It is also highly palatable to most horses. Recommended doses range from 3/4-1.0 oz. per application (your individual needs may vary).
Ride-Rite electrolytes, made by A.B.C. contains Jeannie Waldron`s formulation with additional K citrate, Ca sulfate, amino acetic acid, Mg sulfate, Na sulfate, Si dioxide, etc. These additional ingredients act as "buffers" to the highly acidic chlorides and acetates. A.B.C. recommends feeding these electrolytes in conjunction with Pro-Bi to maintain gut sounds and deter appetite suppression.
Acculytes are designed to be fed daily as a topical dressing. It is not very soluble at all. I personally do not recommend using this as an oral dose via syringe.
Apple Dex is a very palatable electrolyte with sugars. It works best as an additive to the water bucket for free choice application.
Jeannie Waldron`s and Perforn `N Win electrolytes have been extensively field tested on horses doing what YOU do--endurance racing and CTR`s. These products merit your careful consideration for addition to your conditioning/racing program.