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Abstract：
In beef production herds, unique situations such as breeding system, economic parameters, and current phenotypic performance can affect the emphasis of traits in the breeding goal and consequently the weighting of traits within a selection index. An often overlooked component of breeding goals is the planning horizon, or the time span to consider the economic impact of a selection decision, that varies between enterprises. A platform for constructing economic selection indexes (iGENDEC) was used to determine the impact of planning horizon length, breeding system, and sale endpoint on the relative emphasis of traits in the breeding goal and the re-ranking of selection candidates. As part of this investigation, the adjustment of phenotypic means for hot carcass weight and planning horizons were used to determine the impact of the relative emphasis on hot carcass weight as its mean approached a predetermined discount threshold. General-purpose indexes were created for animals sold at weaning and slaughter for three breeding systems with six different planning horizons (2, 5, 10, 20, 30, and 50 yr). As planning horizon increased, the relative emphasis on weaning weight or hot carcass weight, which affected revenue, decreased while the relative emphasis on stayability and mature weight increased. As the phenotypic mean for hot carcass weight approached and surpassed a predetermined discount threshold, the relative emphasis decreased before increasing again, once the mean weight surpassed the threshold. Rank correlations between indexes with different sale endpoints was 0.71 ± 0.1. Within a slaughter endpoint, re-ranking occurred between short and long planning horizons (r = 0.78 ± 0.09) while that of a weaning endpoint was less substantial (r = 0.85 ± 0.10). Jacard index scores between indexes with different planning horizons ranged from 39.7% to 87.9% and from 47.9% to 78.7% for weaning and carcass endpoints, respectively, for the top 5% of selection candidates. These results illustrate that the determination of a planning horizon can impact the rank of selection candidates and increases in net profit.
摘要：
在牛肉生产的牛群中，独特的情况，如育种系统，经济参数，和当前的表型表现会影响育种目标中性状的重点，从而影响选择指数中性状的权重。育种目标的一个经常被忽视的组成部分是规划视野，或考虑选择决策的经济影响的时间跨度，企业之间的差异。构建经济选择指标（iGENDEC）的平台用于确定规划水平长度的影响，育种系统,和销售终点取决于育种目标中性状的相对重点和选择候选物的重新排名。作为调查的一部分,对热car体重量和计划范围的表型平均值进行调整，以确定相对重视对热car体重量的影响，因为其平均值接近预定的折扣阈值。为具有六个不同计划范围（2、5、10、20、30和50年）的三个育种系统在断奶和屠宰时出售的动物创建了通用指数。随着规划视野的增加，相对强调断奶重量或热car体重量，这影响了收入，下降，而对稳定性和成熟体重的相对重视增加。当热car体重量的表型平均值接近并超过预定的折扣阈值时，相对重点在再次增加之前有所下降，一旦平均体重超过阈值。具有不同销售终点的指标之间的排名相关性为0.71±0.1。在屠杀终点内，重新排序发生在短期和长期计划范围之间（r=0.78±0.09），而断奶终点则不那么重要（r=0.85±0.10）。在断奶和car体终点方面，不同计划范围的指标之间的Jacard指数得分在39.7％至87.9％和47.9％至78.7％之间，分别,选择前5%的候选人。这些结果表明，规划范围的确定会影响选拔候选人的排名和净利润的增加。
