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Bioeconomic efficiency of cows of different milk yield levels per lactation and feeding strategies

This work was carried out to evaluate the bioeconomic efficiency of cows of different levels of milk yield per lactation, under different feeding strategies. The bioeconomic evaluations was carried out in cows of five milk yield levels and seven feeding strategies The simulation model was developed with the programs CNCPS v5.0 and electronic spreadsheets of Microsoft Excell®, in way to simulate the production and demands of nutrients of a complete lactation for cows of different milk yield levels. The bioeconomic efficiency (EBE) were evaluated in cows of five milk yield levels, in seven feeding strategies. The EBE was defined similarly to the biological efficiency, considering the amount of feeds utilized and the milk production obtained, multiplied by the respective economical values. Also, with the purpose of evaluating EBE of the cows of each production level, were evaluated the medium physical product (PFme) and the marginal physical product (PFma) for each production level and feeding strategy. In the evaluation of PFma, regression equations of milk yield per cow in function of concentrate level utilization and total feeding costs were estimate. The largest biological efficiency of cows of greater milk yield per lactation not result, necessarily, in larger bioeconomic efficiency. The efficiency of the use of concentrate, when evaluated in crescent milk yield per cows, follows the law of the decreasing returns and influences the bioeconomic efficiency as higher is the milk production level per cow.

bioeconomic efficiency; dairy cows; simulation


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