黒毛和種若雌牛の外貌記載形質に関与する要因

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The objectives of this study are to investigate the inheritance of type traits and to obtain some means to select for carcass value in Japanese Beef Cattle. At first, factors affecting 28 descriptive type traits and final score were studied. The type traits were evaluated by the descriptive classification method which was instituted by the Wagyu Registry Association in Japan. The data on 1338 heifers, belonging to 89 sires, which had been raised in five different prefectures and averaged 23.6 months old were recorded by the Association in 1973 and 1974. A least square analysis with regression was carried out as described by HARVEY. Each trait was classified by region where the heifer had been raised, by year when it was judged, by sire to which it belonged and its age at judging. Over all means of descriptive traits indicated that hair color and skin color in quality, fore quarter, rib and belly in middle quarter, etc. had been considerably improved in heifers, while impressiveness, thigh in hind quarter, etc. had not been yet. All traits with the exception of "neck" and "udder" were affected significantly by region. Some traits, especially quality and dairy characters were affected by year and by the interaction between region and year. The image of heifer herds in each prefecture was provided by least square means by region and year. That is, the herd in Hyogo prefecture was excellent in quality characters, while that in Kagoshima was excellent in body capacity and stature, fore quarter, middle quarter and hind quarter characters. The herd in Tottori demonstrated the same pattern as that in Kagoshima. Least square means in Miyazaki were equal or superior to over all means in all traits. Partial linear or cubic regression coefficients of several traits on age at judging were significant and negative. Sire effect was significant in all traits except for "shoulder (side view)", "loin" and "feet". It was suggested from these results that characteristics in type of both an animal and a herd could be visualized by the descriptive classification method. Genetic differences were found in most of 28 traits, which would provide breeders with the useful information for selection.
社団法人日本畜産学会の論文

黒毛和種若雌牛の外貌記載形質に関与する要因

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