The origin of the aAa method can be found in the work of Bill Weeks, an American classifier. After years of inspecting thousands of cows, he discovered a correlation between certain characteristics of a cows build and her performance. He also discovered the existence of certain qualities on which he based his method.
A cow is not made up of loose parts, but parts that that are connected in functional terms. Certain parts of a cows body influence the functioning of other body parts. For example, a weak back and loin affects the position of the pelvis. Narrow pin bones affects the
position of the hind legs and the udder, and the position of the thurls has consequences for the hind legs and feet of the cow. Some of these traits of specific parts are more strongly correlated than others. We can distinguish between six groups of strongly correlated traits. These groups are called qualities and are numbered one to six. (1 to 6).
A cow or bull never has only one single quality, but some have all of them. The “perfect” cow has an equal amount and a reasonable level of all qualities and is “balanced”. This does, however, not occur often in reality. There’s almost always one quality that is more or less dominant.
Every cow or bull can be analyzed on the basis of the 6 numbers of the qualities called the aAa code. Eg. 135462. The bulls numbers represents the qualities he transmits while the cows numbers represent the qualities she needs.