00227305

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クロゲ ワシュ キョセイギュウ ニオケル ヒイク キカンチュウ ノ タイジュウ オヨビ タイケイ ソクテイチ ト エダニク ケイシツ トノ イデン ソウカン

Genetic Correlations between Carcass Traits and Body Weight or Measurements at Various Ages during a Fattening Period in Japanese Black Steers

Japanese (日本語)

神戸大学農学部研究報告

15(2)

437-444

神戸大学農学部

1983-01-30

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。

Genetic correlations between carcass traits and body weight or measurements, and also those between carcass traits and relative growth rates (RGR_s) for measurements over 4 subsequent periods were calculated. Body weight and measurements which were periodically recorded from average 266 days up to average 567 days of age, and carcass traits were obtained 732 steers sired by 127 Japanese Black bulls progeny tested during 1971-1977 at 9 testing stations in Japan. Least squares analysis based on Method 3 of Henderson (1953) was used to estimate the variance and covariance components. There were the moderate or high genetic correlations between carcass weight and body weight or measurements recorded at all ages. Dressing percentage had the positive genetic correlations with body weight, chest girth and width, and pin-bone width at all ages. Rib eye area had no or negative correlations with each measurement except for chest girth and width, croup length, and hip and thurl width which were measured at the end of fattening. Generally the negative genetic correlations were found between marbling score or back fat thickness and each body measurement with some exceptions. That is, chest depth at all ages was positively correlated with marbling score. Also body weight, chest girth, and chest and hip width showed the positive relationships to back fat thickness and those relations were the highest at about 350 ddays of age. On the other hand, the genetic correlations between carcass traits and RGR_s varied remarkably during the fattening period as compared with those between carcass traits and measurements at each age. Carcass weight and rib eye area had a tendency to be independently or negatively correlated with RGR_s in the first period, but turned to have positive and sizable correlations in the latter half. However, the genetic correlations between marbling score and RGR_s, in particular RGR_s of chest girth and body widths, changed in the opposite manner as the trend in the correlations between carcass weight or rib eye area and RGR_s. These results indicate that selection of any one of body measurements would result in correlated response in carcass traits, but the direction of response is dependent on the age at measured and largely determined by the composition of growth attained in the time interval under question.

紀要論文