Data from a three-year study conducted to integrate pasturing systems with drylot feeding systems were used to assess cultural energy analysis of the cattle production systems. Each year, 84 fall-born and 28 spring-born calves of similar genotypes were brought from Oklahoma and used in the experiment. Fall-born and spring-born calves were started on test in May and October, respectively. Seven treatments were imposed: (1) fall-born calves directly into feedlot; (2) and (3) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of July; (4) and (5) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October; and (6) and (7) spring-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October. A 12.1 ha bromegrass pasture was available and divided into 16 paddocks of 0.69 ha each. Each treatment group had access to one paddock at a time and was rotated through one of four paddocks at approximately 3-day intervals. In the feedlot, steers were provided an 82% concentrate diet containing whole-shelled corn; ground alfalfa hay; and a protein, vitamin, and mineral supplement containing ionophore and molasses. When pens of cattle reached approximately 522 kg average live weight, they were processed into beef. Cultural energy used for pasture establishment and maintenance was calculated using the actual inputs and their corresponding energy values from literature. Cultural energy used for feedlot operations for Kansas feedlots obtained from literature was used. Cultural energy used for feed for treatments was derived from their corresponding lot feed consumption and their corresponding values from literature. Transportation energy was also included in the analysis. Since the objective of the study was to evaluate cultural energy analysis of the feeding systems, energy that the calves had deposited in their muscle and fat tissue when they were bought was deducted from carcass energy. Cattle going directly to feedlot had higher total cultural energy expenditures and those that spent longer time on pasture had lower than other treatments (P < 0.01). Feed energy constituted more than half of the total cultural energy and was highest for cattle going directly to feedlot and lowest for cattle spending the longest time on pasture (P < 0.01). Energy expended per kg live weight was highest for spring-born cattle (P < 0.01). The more time cattle spent on pasture, the lower was the energy output ratio defined as kcal input/kcal output (P < 0.01). Results show that pasturing for cattle is an effective way of reducing cultural energy expenditure and could be used to enhance the sustainability of agriculture and energy conservation.