Population structure of subpopulations of Japanese black cattle divided by the local districts in Hyogo prefecture [Japan]
1996
Takayanagi, S. (Kyoto Univ. (Japan). Coll. of Agriculture) | Moriya, K. | Nomura, T. | Dohgo, T. | Sasaki, Y.
Pedigree analysis was carried out on subpopulations of Japanese Black cattle in Hyogo prefecture, considering herds raised in the local districts as the subpopulation. Twenty Japanese Black registered heifers produced in 1960, 1970, 1980 or 1988 in Hyogo prefecture were ramdomly selected from each of 9 local districts. Population genetic parameters, such as the index of diversity of sires, the effective sire number, F-statistics (F-it, F-st and F-is), the index of subdivision and the average coefficients of relationship within and between districts, were estimated. The diversity of sires increased from 1960 to 1980 in most of the districts, while decreased in 1988. The average inbreeding coefficient for heifers (F-it) and the average inbreeding coefficient expected by random mating of the parents of heifers (F-st) increased for all districts. The inbreeding coefficient due to consanguine mating (F-is) and the index of subdivision decreased in many districts. The average coefficients of relationship within and between districts increased year by year, with the latter approaching the former. The results of this study indicate that the population of Japanese Black cattle in Hyogo prefecture has become genetically homogeneous through the dispersion of genes from one district to others
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