Bioeconomic evaluation of pasture sheep finishing using castor bean cake

Abstract This study evaluates the economic viability of sheep finishing systems on irrigated Tamani grass pasture under continuous stocking, using castor bean cake. Four production systems were simulated: sheep supplemented with soybean meal on pasture fertilized with urea (SMUR), sheep supplemented with detoxified castor bean cake on pasture fertilized with urea (CCdUR), sheep supplemented with soybean meal on pasture fertilized with in natura castor bean cake (SMCC) and sheep supplemented with detoxified castor bean cake on pasture fertilized with in natura castor bean cake (CCdCC). A minimum unit of 3 hectares and an average slaughter weight of 28 kg were considered. A minimum selling price, at which the least profitable system would become profitable, was stablished: US$ 2.38 and US$ 4.45/kg per kilogram of body weight and carcass weight equivalent, adopting a minimum rate of return of 3.5% per year, based on the Selic rate. The costs for organic fertilization were 46.01% higher than in systems using chemical fertilization. The selling of live animals was not attractive in any of the systems evaluated, and the opposite was observed for the selling of carcasses and non-carcass components. System SMUR proved to be more profitable, with a gain of US$ 0.53 per kg carcass.

摘要：本研究针对连续放牧制度下灌溉型塔玛尼草牧场的肉羊育肥系统（辅以蓖麻籽饼）开展经济可行性评估。共模拟了四类生产系统：牧场施用尿素并补饲豆粕的肉羊育肥系统（SMUR）、牧场施用尿素并补饲脱毒蓖麻籽饼的肉羊育肥系统（CCdUR）、牧场施用原生蓖麻籽饼并补饲豆粕的肉羊育肥系统（SMCC），以及牧场施用原生蓖麻籽饼并补饲脱毒蓖麻籽饼的肉羊育肥系统（CCdCC）。本研究设定最低牧场规模为3公顷，平均屠宰体重为28千克。以3.5%的年最低收益率为基准（参照塞尔伊克基准利率），确定了使盈利能力最弱的系统实现盈利的最低售价：按活体重与胴体重当量计算，售价分别为2.38美元/千克和4.45美元/千克。有机肥施用成本较化肥施用系统高出46.01%。所有评估系统中，活畜销售均无经济吸引力，而胴体与非胴体组分的销售则呈现相反态势。系统SMUR的盈利能力最优，每千克胴体可获利0.53美元。