Relationship of Parts
aAa® Animal Analysis founder, Bill Weeks, showed that the lack of a quality in one area of a cow can lead to problems in function or performance in other areas of the cow. This is the principle of relationship of parts. These functions include standing, walking, eating, calving, will to milk and milk let-down, blood circulation, breathing and strength of immune system.
Bill observed that the manner in which the parts of a cow are formed together has a relationship to how the cow functions. He realized that each parent in a mating displays a specific physical pattern, which is defined by the genetics of its parents. The patterns Bill Weeks identified are based on the same six aAa® numbers used by aAa® and Weeks® Approved Analyzers today: 1 – Dairy, 2 – Tall, 3 – Open, 4 – Strong, 5 – Smooth, and 6 – Style.
Bill Weeks also identified a fundamental concept that significantly affects breeding results: a problem in several different cows may look the same, but the cause of the problem may be for different reasons. The fundamental point of aAa® analysis is that relationship of parts is the basis for understanding the different causes of a problem.
For example, a “bulgy front udder” may be caused by lack of space for the udder in the pelvic cavity, which results in a squeezed and “spread” front udder. This relationship between pelvic capacity and front udder attachment shows a need for aAa® and Weeks® number 3 – Open.
On the other hand, a “bulgy front udder” may be caused by ineffective circulation of blood, resulting in a swollen and inflamed front udder. This is a relationship between the strength of the front end and its ability to oxygenate and pump blood to the udder to produce milk and fight infection, indicating a need for aAa® and Weeks® number 4 – Strong.
Or, a “bulgy front udder” may be a “meaty” front udder by nature, and may not milk out completely due to a lack of elasticity and excess udder tissue. This is a relationship between udder texture and milk out, and shows a need for aAa® and Weeks® number 2 – Tall.
Understanding the cause of a cow’s problem is essential in order to choose a bull whose strengths complement a cow’s weaknesses.