One disadvantage of selection is that some good traits may be eliminated.
Selection is the process of choosing individuals with desirable traits for breeding purposes. While this process can result in improvement of the population over time, it can also have the unintended consequence of eliminating some good traits that were not the focus of the selection process.
For example, if a farmer is only selecting for larger size in their livestock, they may unintentionally eliminate traits such as hardiness or disease resistance that are also important for the health and survival of the animals.
This is why it is important to consider multiple traits when selecting individuals for breeding, and to be mindful of the potential trade-offs between different traits. By considering a variety of factors, farmers can help to ensure that their populations continue to be healthy and productive over time.