The beginning of the confinement cycles, starting in April in various regions of Brazil, reinforces the need for attention to the adaptation of cattle within intensive systems. The entry of animals with different origins and sanitary histories has become the main challenge for cattle ranchers. Contrary to what one might think, the biggest risks are not related to ectoparasites, but rather to the heterogeneity of the lots, which can compromise performance and increase production costs. Animals coming from different properties arrive at the confinement with varied levels of immunity and exposure to pathogens. This scenario increases the predisposition to diseases such as pneumonia, clostridial diseases, and difficulties in dietary adaptation. The lack of uniformity directly impacts the predictability of results, making the system more sensitive to performance variations and requiring more technical management. Despite the common concern about ticks and horn flies, the confinement ...