Abstract Data suggests crossbreeding a Romney ewe flock with Merino sires to achieve a second cross ¾ Merino ¼ Romney (¾M¼R) flock would reduce wool fibre diameter and increase income from wool sales. It is not known how cashflow would vary during such a breed transition and which factors would affect the profitability of such a strategy. A bio-economic system-dynamics modelling study was conducted to simulate the breed transition with low or high selection intensity (24 % vs. 35 % of crossbred ewe lambs not retained at each of two selection events) and either consistent lambing rate (132 % for all flocks) or breed specific lambing rate (lower for Merino-Romney crossbred flocks). Although sheep enterprise profit was always greater post-transition compared with the base Romney flock, during transition annual profit was reduced below that of the base Romney flock. The total cashflow of the breed transition (i.e. twelve years) ranged from relatively small or no economic benefit, to up to 26 % greater than maintenance of the base Romney flock. The most profitable breed transition strategies modelled had higher Merino-Romney ewe lamb selection intensity, achieved greater wool fibre diameter reductions, and occurred over a longer breed transition period.

中文翻译：

---

通过从 Romney 到 Merino 杂交生产更高价值的羊毛 ii：现金流和利润

摘要 数据表明，将罗姆尼母羊群与美利奴公牛杂交以获得第二个 ¾ 美利奴 ¼ 罗姆尼 (¾M¼R) 羊群将减少羊毛纤维直径并增加羊毛销售收入。目前尚不清楚在这种品种过渡期间现金流会如何变化，以及哪些因素会影响这种策略的盈利能力。进行了一项生物经济系统动力学建模研究，以模拟具有低或高选择强度（24 % 与 35 % 的杂交母羊羔羊在两次选择事件中均未保留）和一致产羔率（132 %）下的品种过渡所有羊群）或品种特定的产羔率（美利奴-罗姆尼杂交羊群较低）。尽管与基础的罗姆尼羊群相比，羊企业的利润在转型后总是更大，在过渡期间，年利润减少到低于基本罗姆尼鸡群的利润。品种过渡（即十二年）的总现金流量范围从相对较小或没有经济效益，到比维持罗姆尼基础鸡群高 26%。建模的最有利可图的品种过渡策略具有更高的美利奴-罗姆尼母羊羔羊选择强度，实现了更大的羊毛纤维直径减少，并且发生在更长的品种过渡期。