There are twenty amino acids known that make up the building blocks for mammalian body protein. Approximately one-half of the amino acids are essential (this means the body is unable to make those nutrients; therefore, the nutrients must be ingested). Methionine is an essential amino acid that can be converted to cystine by the body.
Cystine and the Horse
Cystine is important because it furnishes the sulfur crosslinks that are necessary for healthy collagen, thus strong hoof infrastructure (hoof, skin, hair, ligaments, tendons, and cartilage). A certain quantity of essential amino acids can be manufactured by the micro organisms in the hind gut of the equine.
Methionine
Most hoof supplements containing methionine is the DL-methionine form. L-methionine is the biologically active form amounting to approximately 50% of the total DL-methionine. A supplement containing 6,000 milligrams of DL-methionine would contain 3,000 milligrams of the biologically active L form. There is no data on the equine requirements of methionine; however, the average requirements for other species converted to the metabolic size of a horse amounts to approximately 3,000 milligrams of L-methionine per day.
Because methionine is readily converted to cystine by the liver in mammals it is necessary to supplement only methionine to fulfill the methionine/cystine requirement.
J. Frank Gravlee, DVM, MS, CNS
Founder of Life Data Labs, Inc.
Developer of Farrier’s Formula®