Effect of carcass price fluctuations on genetic and economic evaluation of carcass traits in Japanese Black cattle
Effect of carcass price fluctuations on genetic and economic evaluation of carcass traits in Japanese Black cattle
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DOI：
10.2527/jas.2005-610
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发表时间：
2006-12-01
影响因子：
3.3
通讯作者：
Hirooka, H.
中科院分区：
文献类型：
--
作者：
Ibi, T.;Kahi, A. K.;Hirooka, H.
本研究的目的是：1）调查牛海绵状脑病（BSE）发生导致的胴体市场价格变化对胴体性状的遗传参数和经济权重估计值的影响; 2）比较直接和间接方法预测日本黑牛的遗传价值及其后代的盈利能力。直接方法利用估计的育种价值的胴体价格，而在间接方法中，选择指数被构造为产品的经济权重和育种价值的组成性状。数据由80，191个胴体记录组成，根据日本和美国发生BSE导致的胴体价格变化分为5个时期。这些时期从日本发生疯牛病之前的时期到牛肉进口限制和价格上涨的时期。分析的胴体性状包括HCW、LM面积、肋骨厚度、皮下脂肪厚度和大理石花纹评分（MS）。价格性状包括胴体单价和胴体销售价格。价格性状的遗传力估计值为中等（0.32至0.46），对胴体市场价格的变化稍敏感。随着时间的推移，肥育猪胴体重和屠宰面积与胴体价格性状的遗传相关性逐渐增大，而肥育猪胴体销售价格与胴体重的遗传相关性逐渐减小，而肥育猪胴体重与胴体单价的遗传相关性在各时期均较高（0.96 ~ 0.98）。胴体性状的经济权重随时期而变化，因为胴体价格对性状的经济重要性高度敏感。然而，使用直接和间接方法估计的价格性状的期间内育种值之间的相关性很高（0.92至0.99）。这一结果表明，通过直接和间接方法实现的选择将提供非常相似的结果。在不同时期内的方法育种值估计之间的比较表明，最大的价格性状的育种值的公畜之间的差异是在日本和美国发生疯牛病后的时期。牛海绵状脑病发生的经济影响的重要性，胴体性状和经济价值的价格性状，通过改变胴体价格从一个时期到另一个时期，无论采取的方法，在确定育种动物的遗传价值，其后代的盈利能力。
The objectives of this study were 1) to investigate the effect of changes in carcass market prices due to bovine spongiform encephalopathy (BSE) occurrences on estimates of genetic parameters and economic weights for carcass traits; and 2) to compare direct and indirect approaches for prediction of genetic merit of Japanese Black cattle for profitability of their progeny. The direct approach utilized estimated breeding values of carcass prices, whereas in the indirect approach, selection indices were constructed as products of economic weights and breeding values of component traits. Data were composed of 80,191 carcass records divided into 5 periods based on changes in carcass prices as a result of occurrences of BSE in Japan and the United States. The periods ranged from a period before occurrence of BSE in Japan to a period of beef import restrictions and a rise in prices. Carcass traits analyzed included HCW, LM area, rib thickness, subcutaneous fat thickness, and marbling score (MS). Price traits included carcass unit price and carcass sale price. Estimates of heritability for price traits were moderate (0.32 to 0.46) and slightly sensitive to changes in carcass market prices. Genetic correlations of HCW and LM area with price traits increased and that between MS and carcass sale price decreased with period, whereas estimates of genetic correlation between MS and carcass unit price were high in all periods (0.96 to 0.98). Economic weights for carcass traits varied with periods because carcass prices were highly sensitive to economic importance of traits. Nevertheless, correlations between within-period breeding values for price traits estimated using direct and indirect approaches were high (0.92 to 0.99). This result indicates that selection realized by direct and indirect approaches will provide very similar results. A comparison among within-approach breeding values estimated in different periods showed that the largest differences in breeding values of sires for price traits were between the periods after occurrences of BSE in Japan and in the United States. Economic effects of BSE occurrences influenced the importance of carcass traits and economic merits of price traits through a change of carcass prices from period to period, irrespective of the approach taken in determining the genetic merit of breeding animals for profitability of their progeny.