Which trait is considered most important when evaluating dairy cattle?

When evaluating dairy cattle, the mammary system or udder is considered the most important trait because it is directly related to a cow's ability to produce milk efficiently. A well-developed and properly structured udder allows for optimal milk storage and ease of milking, which are crucial for high milk production. The mammary system's health and functionality significantly impact a cow's overall productivity and longevity in the dairy herd.

Additionally, a strong and balanced udder can prevent issues such as mastitis (an infection of the udder), which can severely affect milk yield and quality. The udder's shape and attachment also influence how much milk can be collected during milking sessions, as well as the comfort and well-being of the animal. Therefore, prioritizing the evaluation of the udder is essential when making decisions about breeding and herd management in dairy operations.