The study aimed to find the best selection indices for breeding dairy cattle in Iran by combining different traits like milk yield, reproduction, and udder health. Using a software called SelAction, researchers found that an index including all these traits led to the highest genetic and economic gains. When restrictions were placed on certain traits, the economic gain decreased, depending on the heritability and correlation of the restricted traits. Overall, indices based on records of 200 offspring were 4.819% more efficient than those based on 100 offspring.