デュロック種の肢蹄形質と産肉能力,体尺測定値との関連 [in Japanese] Relationship of Leg Soundness Trait to Meat Performance and Body Size in Duroc Swine [in Japanese]
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外観形状による肢蹄の5段階評価と管囲を肢蹄形質とし, 肢蹄形質と産肉能力の関連を検討するとともに, 肢蹄形質の遺伝率を推定した。デュロック種, 雄50頭, 雌149頭, 去勢59頭の計258頭を供試した。体重が30kgから105kgまで雄は単飼, 雌と去勢は9頭群飼とし, いずれも不断給餌とした。体重105kg到達後, 全頭について体尺測定と産肉能力の測定および前肢・後肢の評価を行った。前肢得点と背脂肪厚との表型相関は全ての性で負の値を示し, 特に体長1/2部位より前の部位の背脂肪厚と高い負の相関を示した。後肢得点と背脂肪厚との表型相関は性によって異なる傾向を示し, 雄では正, 雌と去勢では負の相関を示した。前・後肢得点と体の幅, 特に胸幅との表型相関は雄では低いが, 雌と去勢では負の相関が認められた。肢蹄得点, 管囲と産肉能力, 体尺測定値の遺伝相関についても表型相関と同様の傾向が認められた。肢蹄得点について, 分散分析法で推定した遺伝率は前肢得点0.306, 後肢得点0.231で中程度の値を示した。管囲については前管囲0.429, 後管囲0.414でほぼ同程度の高い遺伝率を示し, 改良の可能性が示唆された。
A total of 258 Duroc pigs (50 boars, 149 gilts and 59 barrows) was used to investigate the relationships of leg soundness traits to meat performance and body size. Leg soundness score and the circumference of fore shank and hind shank were recorded, and heritabilities of leg soundness traits were estimated. Boars were reared individually and approximately 8-9 gilts and barrows were housed per pen, and they were fed <i>ad libitum</i> to grow from 30kg to 105kg of live weight. Meat performance traits, body size and the shortest circumference of fore shank and hind shank were recorded at 105kg of live weight. Leg soundness scores of the fore legs and hind legs were also marked for their structure using the NPPC method. The phenotypic and genetic correlations of fore leg soundness score with back fat thickness (BF) measured at five different positions were all negative and highly negative correlations of fore leg soundness score with BF at the fore part of the body were obtained. The phenotypic correlations between hind leg soundness score and BF were different in sex; positive values were observed only for boars and the values of gilts and barrows were negative. The phenotypic correlations between fore leg soundness score and chest width were low for boars, but values of gilts and barrows were negative. Although the genetic correlations between leg soundness scores and chest width were all negative, the values between leg soundness scores and body height were found to be positive. Heritabilities of leg soundness traits estimated by analysis of variance were .306, .231, .429 and .414 for fore and hind leg soundness score, and the circumference of fore shank and hind shank, respectively.
- Nihon Yoton Gakkaishi
Nihon Yoton Gakkaishi 35(3), 107-113, 1998-09-25
The Japanese Society of Swine Science