Jun-Kyu Son

Genome scan linkage analysis identifies a major quantitative trait loci for fatty acid composition in longissimus dorsi muscle in an F2 intercross between Landrace and Korean native pigs.

Objective This study was conducted to locate quantitative trait loci (QTL) influencing fatty acid (FA) composition in a large F2 intercross between Landrace and Korean native pigs. Methods Eighteen FA composition traits were measured in more than 960 F2 progeny. All experimental animals were genotyped with 165 microsatellite markers located throughout the pig autosomes. Results We detected 112 QTLs for the FA composition; Forty seven QTLs reached the genome-wide significant threshold. In particular, we identified a cluster of highly significant QTLs for FA composition on SSC12. QTL for polyunsaturated fatty acid on pig chromosome 12 (F-value = 97.2 under additive and dominance model, nominal p-value 3.6×10−39) accounted for 16.9% of phenotypic variance. In addition, four more QTLs for C18:1, C18:2, C20:4, and monounsaturated fatty acids on the similar position explained more than 10% of phenotypic variance. Conclusion Our findings of a major QTL for FA composition presented here could provide helpful information to locate causative variants to improve meat quality traits in pigs.

Effects of Lactation Stage and Milk Yield on Reproductive Performance in Holstein Dairy Cows

【This study aimed to improve the reproductive efficiency of dairy herds by comparison and analyzing estrous appearance rate, conception and non-conception rate according to the stage of lactation using the lactation and reproductive records of average (less than 10,000 liters milk in 305 days) and high yielding (more than 10,000 liters milk in 305 days) Holstein cows (n=102). Milk production and reproduction data were collected between January 2010 and December 2012 from Holstein cows kept in the commercial dairy farms. Average (n=32) and high yielding (n=24) Holstein cows used to analyze the relationship between milk yield and reproductive performance. Our results showed that estrous appearance rate according to the stage of lactation was 25.0% (30~59d), 40.6% (60~89d), 25% (90~110d) and 9.4% (>111d) in average yielding cows and 16.7% (30~59d), 20.8% (60~89d), 12.5% (90~110d) and 50.0% (>111d) in high yielding cows, respectively. Conception rate according to the stage of lactation was 87.5% (30~59d), 61.5% (60~89d), 75.0% (90~110d) and 66.7% (>111d) in average yielding cows and 25.0% (30~59d), 0% (60~89d), 33.3% (90~110d) and 50.0% (>111d) in high yielding cows, respectively. Days between parturition and conception was 23.7% ( 210 d) in average yielding cows and 69.0% ( 210d) in high yielding cows, respectively. Conception rate from 110 days postpartum in high yielding cows was 41.7% (110~150d), 50.0% (151~180d) and 50.0% (>181d). Body condition score (BCS) in 120 days postpartum was

Embryo Gender Ratio and Developmental Potential after Biopsy of In Vivo and In Vitro Produced Hanwoo Embryos

2.64{\pm}0.1

88 SURVIVAL AFTER FREEZING OF IN VITRO AND IN VIVO BOVINE EMBRYOS

in average yielding cows and

A Survey of Disease Occurrence in Korean Black Goats

2.28{\pm}0.1

Effect of Pentoxifylline Concentration on Sperm Quality in Jeju Crossbred Horses

in high yielding cows, respectively.】

Effect of Ovarian Changes according to Four Season for Reproduction of Jeju Crossbred Horses

The present study was to assess the in vitro viability and sexing rate of bovine embryos. Blastocysts were harvested on day 7~9 day after insemination(in vitro and in vivo), and the sex of the embryos was examined using the LAMP method. Embryo cell biopsy was carried out in a 80 μl drop Ca, Mg 2+ free D-PBS and, biopsied embryos viability were evaluated after more 12 h culture in IVMD culture medium. The formation of recovered embryo to expanded and hatching stages had ensued in higher of sexed embryo in vivo than in vitro (100% vs. 89%, p<0.05), and in vitro, the rates of degeneration after sexing were significantly (p<0.05) higher in vitro than in vivo(11% vs. 0.0%). The rates of the predicted sex were female 61% vs. 56%, and male 39% vs. 44% in vivo and in vitro, respectively. The rates of survival following different biopsy methods were seen between punching and bisection method in vivo and in vitro (100% vs. 89% and 100% vs, 78% respectively). Biopsy method by punching was significantly (p<0.05) higher than bisection between produced embryos in vivo and in vitro. The present data indicate that with microblade after punching for embryo sexing results in high incidence of survivability on development after embryo biopsy. It is also suggested that LAMP-based embryo sexing suitable for field applications. (