Análise bioeconômica da substituição do farelo de soja pelo de mamona para ovinos em confinamento

Abstract

The objective of this study was to evaluate the effect of different replacement levels of soybean meal by detoxified castor meal by autoclave the bioeconomic evaluation of feed for them. We used 20 lambs, crossbred, male, non-castrated, live weight of 19.3 ± 1.35 kg and average of 7 months old, and randomly assigned to four treatments of 0, 50, 75 and 100% of replacement on the dry matter basis. The roughage used was hay of elephant grass (Pennisetum purpureum Schum.). The diets were isocaloric and isonitrogenous. The experiment lasted 70 days, when the animals were slaughtered. To analize the economic performance of the feed offered in the experiment, were considered the market price obtained for the ingredients of rations and the live weight (PV) of lambs. After the calculation of cost of each diet and consumption of dry matter of them, were analyzed technical, animal production and economic indicators using spreadsheets in Excel® program. Analyzing the profite of activity, any treatments showed profitability. Furthermore, the and net margins (R$/kg PV) and profit (R$/kg PV) obtained, was positive only for the treatment without castor bean meal that only the replacement level of 0% of soybean meal by detoxified castor meal showed positive result for such indices, with values of R$ 0.69/kg PV, R$ 0.66/kg PV and R$ 0.59/kg PV, respectively, when the selling price of live weight was R$ 5.20, this is explained by additional investment in the autoclave for detoxification of castor bean meal, but also with the increasing percentage of concentrate in the diets with 75 and 100% of replacement. The use of castor detoxified meal by autoclave feed for the fattening of lambs in feedlot is not showed a viable alternative to ensure profit to the farmers, because this activity would only be viable if the sale price was more than R$ 9.25/kg PV.