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Objectives: The objectives were to (a) evaluate whether marginal reproductive gains from early weaning (EW) calves of first-calf replacement heifers extend throughout the animal’s productive life and (b) compare via cost–benefit analysis EW with conventional weaning (CW) practices on a vertically integrated ranch in Florida, USA. Materials and Methods: A system dynamics model was developed to evaluate CW versus EW of calves from replacement heifers that calve in the first 21 or 42 d of the calving season. A combination of sensitivity analyses and deterministic management tests (EW vs. CW and 21- vs. 42-d calving seasons) were simulated and compared across a range of 18 production and financial metrics, including net present value, over the useful life of one generation of replacement heifers. We hypothesized that EW calves from replacement heifers would improve reproductive performance, resulting in greater total calves produced and, therefore, improved cow-calf and whole-system profitability. Results and Discussion: The 42-d calving criteria for EW created significant production and financial gains and outperformed the 21-d calving criteria. Counterintuitively, these gains did not arise in the cow-calf or feedyard segments (which saw financial declines) but in the stocker segment due to more efficient livestock gains facilitated by lower weaning weights of incoming calves. Sensitivity analyses corroborated these trade-offs. Feedyard sale price (i.e., value received for finished cattle) was the most influential factor influencing whole-system profitability. Implications and Applications: Trade-offs and incentives between enterprises may provide misleading feedback and mask changes that improve the system as a whole (e.g., EW reduced calf weaning weights and reinforced the reproductive performance pressure on management; gains at the stocker segment may mask EW benefits at the cow-calf level, making the cow-calf enterprise more reliant on short-term adjustments, a behavior known as “shifting the burden”).