The objective of this study was to develop a feedlot beef cattle calculation model and production cost analysis and, from the results obtained, devise a production cost index. A case study was conducted to understand the characteristics of the productive processes of a commercial feedlot. Then, based on the Economic Theory, cost items of the farm under analysis were identified and transferred to a spreadsheet. The survey included ten feedlot farmers from the state of São Paulo and other nine from the state of Goiás and was carried out to determine representative properties, and prices of items used were monitored. Production costs of each farm were calculated, and theoretical concepts of index numbers were used to devise the feedlot cattle production cost index. The cost allocation scheme was divided into four cost groups: variable, semi-fixed, fixed, and production remuneration factors. The developed model allowed a cost prognosis of the analyzed systems. Highest total costs for São Paulo State feedlots were R$ 9.17 kg −1 and R$ 9.08 kg −1 for average-sized and large farms, respectively, as contrasted to that of Goiás, of R$ 8.29 kg −1. Between the months April and June, the cost of production for feedlot beef cattle showed reductions of 1.48 and 1.40% for the average and large feedlots in the State of São Paulo and 9.13% for the Goiás feedlot by the Konüs Exact Index, respectively. Studies available in literature were compared and it was concluded that the model can help feedlot cattle farmers take production decisions. The Konüs Index allows for a methodological advancement in relation to other studies carried out on the Brazilian livestock industry; besides, it can contribute to the sector organization.

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A hybrid stochastic model was developed including discrete events and agent-based simulations in order to identify the productive parameters and management criteria that most affect meat sheep production. A sheep herd on a pasture termination system, without weaning and with natural mating, was outlined. In order to devise this herd, a pre-existing database from between 1999 and 2013 was used. This conceptual model included the flushing, mating, gestation, lactation, termination and maintenance phases. Health, feeding and management criteria were also considered and recommended. Simulation scenarios were built which were later evaluated by regression analysis. The net operational margin was between R$ 11 741.80 and R$ 21 389.80, and an average of R$ 14 412.14 ± R$ 3 873.02 for different scenarios. Food costs had the greatest impact (25.4%) in relation to operating costs, while health costs were the lowest (1.3%). The abortion rate showed a higher linear response in contrast to the birth rate and the net operating margin, upon analysing ewe productivity parameters. However, neonatal mortality showed the greatest impact on net profit and on general lamb mortality. Carrying out economic analyses within the livestock sector can make a difference within such a competitive market, where prices are not controlled, only costs. The use of discrete event and agent-based simulation methodologies allowed for the assessment of different approaches to sheep production. The present study demonstrated the tool’s potential within the scope of meat sheep production, but this model can act as a guideline for other animal production systems.

The objective of this study was to create a stochastic, agent-based simulation model to compare the economic performance of reproductive strategies in beef cattle. The model was parameterized using data from a real herd and the scientific literature. The scenarios evaluated were: natural mating (NM) only (ONM); one timed artificial insemination (TAI) plus NM (1TAI+NM); two TAI plus NM, with 24, 32, and 40 days between TAI (2TAI/24+NM, 2TAI/32+NM, and 2TAI/40+NM, respectively); three TAI without NM, with 24, 32, and 40 days (3TAI/24, 3TAI/32, and 3TAI/40, respectively), and three TAI plus NM, with 24 and 32 days (3TAI/24+NM and 3TAI/32+NM, respectively). The initial female herd was 400 and remained constant. The bull population varies from 0 to 15, depending on the scenario. The outcomes for each scenario are assessed on 32 farms, using a 5000-day time horizon at one-day time intervals and an animal-by-animal basis. The 3TAI/24+NM scenario resulted in the highest incomes (US$ 96,479.2 ± 709.8), while ONM had the least value (US$ 79,753.4 ± 741.9). The total operating cost was highest for 3TAI/24+NM (US$ 101,720.6 ± 79.2) and lowest for ONM (US$ 90,898.6 ± 59.2). However, when the total operating cost was evaluated per kg of weaned calf, the highest and lowest costs were for ONM (US$ 2.8 ± 0.0/kg) and 2TAI/24+NM (US$ 2.17 ± 0.0/kg), respectively. The 2TAI/24+NM (US$ -4,651.3 ± 630.7) scenario presented the best net margin, while the lowest result was for 3TAI/40 (US$ -12,590.0 ± 746.3). Our model suggests that reproductive strategies that use TAI have better economic performance than those under ONM. However, when three TAI were performed with 40 days, the benefit was lower, and even for some analyzes, it was worse than the ONM. The 2TAI/24+NM scenario outperformed the others because of the contrast between its high income with moderate costs.