Nihon Chikusan Gakkaiho
Online ISSN : 1880-8255
Print ISSN : 1346-907X
ISSN-L : 1880-8255
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Review Article
  • Genetic improvements in closed breeding herds of pigs in Japan
    Masahiro SATOH
    2025 Volume 96 Issue 2 Pages 115-126
    Published: May 25, 2025
    Released on J-STAGE: June 06, 2025
    DOIhttps://doi.org/10.2508/chikusan.96.115
    JOURNAL RESTRICTED ACCESS
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    Closed breeding herds of pigs in Japan are used for the development of pig strains (DPS). The program was started in 1969, and has since produced nearly 100 strains. Until the 1990s, the selection index method was used to achieve the relative desired changes, followed by the restricted BLUP method ; and since the 2000s, the BLUP method has been used, which employs weighted values of objective traits for improvement that are estimated from the family selection index. During this latter period, a considerable number of studies have been conducted, including theoretical research on selection methods and inbreeding prevention in DPS, and the estimation of genetic parameters based on actual data obtained from DPS. Traits that were not included at the outset of DPS, such as female reproductive traits, body size, and robustness, have also been added to the list of objective traits. We conclude by discussing the significance of the contribution of DPS to the genetic improvement of pigs in Japan and new genetic improvement methods that have the potential to replace the DPS process.

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Original Articles
  • Phenotypic and genetic analysis of milk β-hydroxybutyrate and fatty acid origin groups and production, reproductive, udder health, and longevity traits of Holsteins in Hokkaido, Japan
    Hayato ABE, Yusaku GOTOH, Satoshi YAMAGUCHI, Satoshi NAKAGAWA, Yuka NA ...
    2025 Volume 96 Issue 2 Pages 127-135
    Published: May 25, 2025
    Released on J-STAGE: June 06, 2025
    DOIhttps://doi.org/10.2508/chikusan.96.127
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    Supplementary material
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    We focused on milk β-hydroxybutyrate and fatty acid origin groups as metabolic indicator traits in Holsteins in Hokkaido, Japan, and we investigated the phenotypic and genetic relationships among the indicator traits and production (305-d milk, fat and protein yield), reproductive (days from calving to first service, days open and conception rate for first service), udder health (maximum somatic cell score within 305-d) and longevity (cow livability and stayability) traits. A least-squares analysis that included the indicator traits as explanatory variables revealed that production traits tended to decline with improvement in the indicator traits, whereas the other traits tended to improve. Heritability estimates for the indicator traits in a multiple-trait animal model were mostly between 0.2 and 0.3. The estimated genetic correlations suggest that genetic selection for the indicator traits causes favorable correlated responses of reproductive and udder health traits but unfavorable responses of production traits. Genetic selection for indicator traits may be possible but, in practice, antagonistic relationships between the indicator traits and production traits should be taken into account.

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  • [title in Japanese]
    [in Japanese], [in Japanese]
    2025 Volume 96 Issue 2 Pages 137-142
    Published: May 25, 2025
    Released on J-STAGE: June 06, 2025
    DOIhttps://doi.org/10.2508/chikusan.96.137
    JOURNAL RESTRICTED ACCESS
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    [in Japanese]
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