Tomiyama M, Oikawa T, Hoque M A, Kanetani T, Mori H
Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
J Anim Sci. 2009 May;87(5):1613-9. doi: 10.2527/jas.2008-1214. Epub 2009 Jan 30.
The objective of this study was to estimate genetic parameters for growth and body composition traits at 60 d of age and at finish in a population of Berkshire pigs and to evaluate the effectiveness of selection at 60 d of age for meat productivity. A total of 4,548 purebred Berkshire (2,344 males and 2,204 females) pigs born between December 1994 and January 2005 were used in this study. The traits analyzed were BW at 60 d of age; daily BW gain from birth to finish, from weaning to 60 d, from weaning to finish, and from 60 d to finish; age at finish; backfat thickness at 60 d of age and at finish; loin eye area at 60 d of age (LEA60) and at finish; and the number of teats. The heritability estimates for BW at 60 d of age, daily BW gain from weaning to 60 d, backfat thickness at 60 d of age, and LEA60 were 0.22, 0.25, 0.49, and 0.22, respectively. The estimated common environmental effect for BW at 60 d of age, daily BW gain from weaning to 60 d, backfat thickness at 60 d of age, and LEA60 were 0.12, 0.13, 0.18, and 0.21, respectively. Therefore, the common environmental effect should be included in the model to analyze traits at 60 d of age. The positive genetic correlation between LEA60 and loin eye area at finish and the negative genetic correlation between LEA60 and backfat thickness at finish indicated that improvement of the ultrasonic loin eye area at 60 d of age may result in favorable correlated responses to the traits at finish, an increase in loin eye area, and a decrease in backfat thickness. In addition, genetic correlations of backfat thickness at 60 d of age with backfat thickness at finish and loin eye area at finish were found to be favorable, indicating that improvement of ultrasonic backfat thickness at 60 d of age may result in greater correlated responses to the traits at finish: an increase in loin eye area and a decrease in backfat thickness. Therefore, constructing a selection scheme that includes body composition traits at 60 d and traits at finish is practical for gaining a greater selection response.
本研究的目的是估计伯克夏猪群体60日龄和育肥结束时生长及体组成性状的遗传参数，并评估60日龄选择对肉用生产力的有效性。本研究使用了1994年12月至2005年1月出生的4548头纯种伯克夏猪（2344头公猪和2204头母猪）。分析的性状包括60日龄体重；从出生到育肥结束、从断奶到60日龄、从断奶到育肥结束以及从60日龄到育肥结束的日体重增加；育肥结束时的年龄；60日龄和育肥结束时的背膘厚度；60日龄（LEA60）和育肥结束时的眼肌面积；以及乳头数。60日龄体重、从断奶到60日龄的日体重增加、60日龄背膘厚度和LEA60的遗传力估计值分别为0.22、0.25、0.49和0.22。60日龄体重、从断奶到60日龄的日体重增加、60日龄背膘厚度和LEA60的估计共同环境效应分别为0.12、0.13、0.18和0.21。因此，在分析60日龄性状的模型中应包含共同环境效应。LEA60与育肥结束时眼肌面积的正遗传相关性以及LEA60与育肥结束时背膘厚度的负遗传相关性表明，60日龄超声眼肌面积的改善可能会对育肥结束时的性状产生有利的相关反应，即眼肌面积增加和背膘厚度降低。此外，发现60日龄背膘厚度与育肥结束时背膘厚度和育肥结束时眼肌面积的遗传相关性良好，这表明60日龄超声背膘厚度的改善可能会对育肥结束时的性状产生更大的相关反应：眼肌面积增加和背膘厚度降低。因此，构建一个包括60日龄体组成性状和育肥结束时性状的选择方案对于获得更大的选择反应是可行的。
