aAa Mating

Many people have heard of aAa Mating, but probably don’t know what it really is. aAa Analysis is a breeding tool that analyzes the structural make-up of the cow in order to breed healthier and more balanced cows. aAa focuses on finding the structural problems of a cow that may cause poor performance. Founder, Bill Weeks called this the “relationship of parts”.

How it Works:

Both cows and bulls are analyzed on six factors: Dairy, Tall, Open, Strong, Smooth, and Style. Cows are given a ranking of which of these traits they are lacking, while bulls are ranked on the traits that they will bring to a mating.

Cows are mated to bulls that have the same numbers, so a cow that is lacking traits 4, 3, 2, will be mated to a bull who is ranked 432. the goal of aAa is to breed cows that have enough “roundness” to live and enough “sharpness” to milk.

Bill Weeks believed that poor quality in one area could lead to poor performance in another. His analysis sought to explain why a cow had a fault, not just simply state that the cow had this fault.

aAa does not take into account any genetic evaluation, just physical traits. aAa works well as a stand-alone mating guide and can be paired with other tools such as genomic testing. Global Genetic Resources markets bulls with aAa numbers to meet any producer’s needs.

One of the best parts about aAa Analysis is it is not breed-specific. It works very well for crossbreeding programs and pure bred programs alike.

If aAa Analysis is something you are interested in, the Weeks Corporation website is a great source for additional information, history, and to find a certified analyzer. find their website at:


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