• Title/Summary/Keyword: research & development

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Pregnancy rate in Hanwoo cows after timed artificial insemination using different sperm concentrations

  • Sung-Sik Kang;Sang-Rae Cho;Ui-Hyung Kim;Yonghwan Kim;Seok-Dong Lee;Myung-Suk Lee;Eunju Kim;Jeong-Il Won;Shil Jin;Hyoun-Ju Kim;Sungwoo Kim;Sun-Sik Jang;Seunghoon Lee
    • Journal of Animal Reproduction and Biotechnology
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    • v.39 no.1
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    • pp.40-47
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    • 2024
  • Background: Sperm quality and the number of sperm introduced into the uterus during artificial insemination (AI) are pivotal factors influencing pregnancy outcomes. However, there have been no reports on the relationship between sperm concentration at AI and sperm quality in Hanwoo cattle. In this study, we examined sperm quality and pregnancy rates after AI using sperm inseminated at different concentrations. Methods: We evaluated the motility, viability, and acrosomal membrane integrity of sperm at different concentrations (10, 15, 18, and 20 million sperm/straw) in 0.5-mL straws. Subsequently, we compared the pregnancy rates after AI with different sperm concentrations. Results: After freeze-thawing, sperm at the assessed concentrations showed similar viability and acrosomal membrane integrity. After AI, cattle in the 10 million group had significantly lower pregnancy rates compared to those in the 18 and 20 million groups. Conversely, there were no statistically significant variances observed between cattle in the 10 and 15 million groups. Conclusions: Sperm at concentrations of 10, 15, 18 and 20 million per straw exhibited comparable motility, viability, and acrosomal membrane integrity. However, a concentration of at least 18 million sperm per straw is required to achieve a consistent rate of pregnancy rate in Hanwoo cattle after AI.

Distribution of Whales and Dolphins in Korean Waters Based on a Sighting Survey from 2000 to 2010 (목시조사(2000-2010)에 의한 한국 연안 고래류의 종류 및 분포)

  • Sohn, Hawsun;Park, Kyum Joon;An, Yong Rock;Choi, Seok Gwan;Kim, Zang Geun;Kim, Hyun Woo;An, Du Hae;Lee, Young Ran;Park, Tae-Geon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.45 no.5
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    • pp.486-492
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    • 2012
  • In the late 1970s, the National Fisheries Research & Development Institute (NFRDI) started cetacean research to submit the Korean whale catch record to the International Whaling Commission. This continued until the moratorium on commercial whaling in 1986. The NFRDI resumed cetacean research with a pilot whale sighting survey in 1999. Subsequently, the NFRDI has conducted 53 cetacean sighting surveys within the Korean exclusive economic zone between 2000 and 2010. The surveys took a total of 760 days and cruising for 23,866 nautical miles. The finless porpoise Neophocaena asiaeorientalis was sighted most frequently (735 times), followed by the minke whale Balaenoptera acutorostrata (396 times), the long-beaked common dolphin Delphinus capensis (102 times), and the Pacific white-sided dolphin Lagenorhynchus obliquidens (27 times). Minke whales were distributed in the Yellow Sea and coastal area of the East Sea from spring to fall. Pacific white-sided dolphin sightings were restricted to the middle and upper coastal areas of the East Sea in summer. Common dolphins were sighted from east of the southern coast to the eastern coast of the Korean Peninsula from spring to fall. Finless porpoise occurred in all Korean coastal areas, except the middle and upper eastern coast.

Development of Polymorphic Microsatellite Markers Suitable for Genetic Linkage Mapping of Olive Flounder Paralichthys olivaceus

  • Kim, Woo-Jin;Shin, Eun-Ha;Kong, Hee Jeong;Nam, Bo-Hye;Kim, Young-Ok;Jung, Hyungtaek;An, Cheul Min
    • Fisheries and Aquatic Sciences
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    • v.16 no.4
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    • pp.303-309
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    • 2013
  • Microsatellite markers are important for gene mapping and for marker-assisted selection. Sixty-five polymorphic microsatellite markers were developed with an enriched partial genomic library from olive flounder Paralichthys olivaceus an important commercial fish species in Korea. The variability of these markers was tested in 30 individuals collected from the East Sea (Korea). The number of alleles for each locus ranged from 2 to 33 (mean, 17.1). Observed and expected heterozygosity as well as polymorphism information content varied from 0.313 to 1.000 (mean, 0.788), from 0.323 to 0.977 (mean, 0.820), and from 0.277 to 0.960 (mean, 0.787), respectively. Nine loci showed significant deviation from the Hardy-Weinberg equilibrium after sequential Bonferroni correction. Analysis with MICROCHECKER suggested the presence of null alleles at five of these loci with estimated null allele frequencies of 0.126-0.285. These new microsatellite markers from genomic libraries will be useful for constructing a P. olivaceus linkage map.