熊本県産褐毛和種集団の繁殖構造

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タイトル別名
  • Breeding Structure of the Japanese Brown Cattle Population in Kumamoto Prefecture
  • クマモト ケンサン カツモウワシュ シュウダン ノ ハンショク コウゾウ

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抄録

In order to clarify changes in the breeding structure of the Japanese Brown Cattle population in Kumamoto Prefecture, breeding cows were sampled from the population at intervals of 5 or 11 years from 1955 to 1990 and the values of inbreeding coefficient, components of current inbreeding and inbreeding expected from relationship, index of subdivision and effective population size were estimated. The results were summarized as follows :1) The inbreeding coefficient of this breed has increased from 0.83% in 1955 to 3.36% in 1990. 2) The average coefficient of relationship has increased from 0.89% in 1955 to 4.21% in 1990 and the values for the Aso and Kuma area were higher than other areas. 3) The index of subdivision (F/F') shows that the local or strain division occured in this breed. 4) The effective population size was reduced to 50% in 1966 as compared with 1955, was double again in 1975 and was reduced to 50% again in 1985. The emigration and immigration of breeding stocks between areas is still happening. 5) Bulls belonging to the Shigetama and Mitsuura line showed high genetic contribution of 64.9% and 23.4%. 6) The breeding population of Japanese Brown Cattle has differentiated between areas, and no tendency to genetic homogeneity has been observed in the past 35 years.

収録刊行物

  • 日本畜産学会報

    日本畜産学会報 62 (9), 878-883, 1991

    公益社団法人 日本畜産学会

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