Freeze Mark Identification Information
The technique is simple and completely painless to the animal. The left side of the neck is shaved andwashed with alcohol, and the mark is applied with an iron that is chilled in liquid nitrogen. The hair at the site of the mark will grow back white and show the identification number.
Although every effort is made to apply freezemarks that are legible, occasionally freezemarks do get blurred. This happens when the animal moves as the iron is applied, resulting in all or some of the identification number becoming illegible.
During the 1970's, information was gathered and studied by Washington State University, the United States Department of Agriculture, The Arabian Horse Registry, and an agent in charge of the Colorado Bureau of Investigation, to research the pros and cons of livestock identification methods.
In 1980 their research was published in an article titled "Freeze Marking and Other Techniques for Identifying Horses" in the Journal of Forensic Science. Dr Keith Farrell of Washington State University, and his wife Pat developed the Alpha-Angle Freeze Mark and horse identification system that has gained recognition internationally. Many top breed associations and the Bureau of Land Management highly support this method of identification.
Each letter of the alphabet was developed to be unalterable, where it could not be changed from one letter to another, such as a P to an R. Each Alpha symbol could be rotated into one of eight positions.
The BLM uses freezemarking to identify captured wild horses and burros. Freezemarking is a permanent, unalterable, and painless way to identify each horse individually. It is applied on the left side of the neck. It follows the International Alpha Angle System, which uses a series of angles and alpha symbols that cannot be altered. The mark contains the Registering Organization (U.S. Government), year of birth, and registration number.
In addition to the freezemark on the left side of the neck, wild horses in long-term pastures are marked on the left croup with four-inch high Arabic numerals that correspond with the last four digits of the freezemark on the neck.
The graph at the right illustrates how to read a BLM freezemark. If a mark is difficult to read, we recommend shaving the left side of the neck. You must know the freezemark of your horse or burro before making an inquiry to a BLM office about the animal.