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シュセイブン ブンセキホウ ニヨル クロゲ ワシュ シュユウギュウ ノ タイケイ ヒョウカ チクサンガク

Application of Principal Componenet Analysis for Defining Size and Shape in Japanese Black Cattle Sires

Japanese (日本語)

神戸大学農学部研究報告

15(1)

169-176

神戸大学農学部

1982

2006-09-15

本文ファイルは、国立情報学研究所CiNiiより提供されたものです。

This study was conducted to evaluate body size and shape of Japanese Black Cattle sires and to classify them according to breeding prefecture where they were produced. The body measurement data consisted of withers height, body length, chest girth, chest depth, hip width and thurl width, which were collected on 149 Japanese Black Cattle sires measured at over 4.5 years old. Principal component analysis was used as a method of defining body size and shape, which was carried out upon the correlation matrix among six common log-transformed body measurements. The first principal component accounted for 64.8% of the total variance, and appeared to be a index of general size factor, because all body measurements in this component had nearly equal and positive coefficients. The second component explained 10.8% of the total variance. This component was composed of positive coefficients for withers height and chest depth, and negative coefficients for hip and thur width. Thus, the second component was a bipolar dimension which contrasted animals with regard to height and width. The third component explained a much smaller percentage (8.2%) of the riginal variance. This dimension was positively correlated with chest depth, though negatively with withers height and body length, and was interpreted as a shape factor concerning to body depth. It was possible to describe distinctive feature of each breeding prefecture by combining the first three principal component scores. Sires bred in Hyogo prefecture were characteristic of the smallest framed with narrow and shallow body comparing to height. On the other hend, sires in Tottori prefecture were characterized by the largest framed of all and broad width. Groups belonging to Hiroshima and Miyazaki where a great number of sires were produced by linecrossing occupied the position between the two extreme size groups, namely Hyogo and Tottori. Body size of sires in Okayama was inferior to those in Tottori, however, they were relatively deep in trunk. Sires in Kagoshima, Ooita and Shimane were simlar in size and shape one another and were closely related to Okayama and Tottori sires. Cluster analysis carried out on correlation matrix among principal component scores, so succeeded in grouping sires according to body size and shape, although it was quite impossible to make the cluster based on correlations among original body measurements instead of component scores. These results suggeted that principal component analysis was a useful method for defining body size and shape of sires.

紀要論文