• Journal of Veterinary Clinics
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• v.31 no.4
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• pp.272-277
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• 2014

This retrospective study evaluated the effect of somatic cell count (SCC) in milk during early lactation on reproductive performance in dairy cows. Data were collected on 774 cows from six dairy farms, including cow parity, dates of previous calving, artificial insemination, pregnancy diagnosis, incidence of postpartum endometritis, reproductive performance (the intervals from calving to first insemination and conception), milk production and SCC. Data on 774 lactations were grouped based on the average first 3 months postpartum linear somatic cell score (SCS) as T1 (< 3.0, n = 521), T2 (3.0 ${\leq}$ and < 4.0, n = 113), and T3 (${\geq}$ 4.0, n = 140) groups. The odds ratio (OR) for the probability of endometritis increased 1.6 (p < 0.05) and 3.2 times (p < 0.0001) in the T2 and T3 groups, respectively, compared with that in the T1 group. The hazard of first insemination by 150 days in milk (DIM) was lower in the T3 group (hazard ratio [HR]: 0.76, p < 0.01) than in the T1 group. First insemination conception rate did not differ among the 3 groups (28.7-34.2%, p > 0.05). The hazard of pregnancy by 365 DIM in the T3 group was lower (HR: 0.75, p < 0.05 respectively) than in the T1 and T2 groups. The SCS during 4 to 7 months postpartum differed (p < 0.0001) among the 3 groups. Farm and cow parity were important risk factors for higher SCS (${\geq}$ 4.0). Multiparous cows were more likely to have a higher SCS (OR: 2.26, p = 0.0005) compared with primiparous cows. In conclusion, higher SCS (${\geq}$ 4.0) during early lactation was associated with decreased reproductive performance of dairy cows.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.85-88
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• 2001

Temperature-related cleavage rates and mitotic intervals (${\tau}_o$) in the far eastern catfish Silurus asotus were studied by averaging the duration of the second and third embryonic divisions to establish effective procedures for chromosome manipulations. At higher temperatures eggs developed faster and underwent more asynchronous development. Mitotic intervals for far eastern catfish were $21.5{\pm}1.4$ min at $22^{\circ}C$, $18.5{\pm}1.2$ min at $24^{\circ}C$, and $14.0{\pm}2.1$ min at $26^{\circ}C$. There was a strong negative correlation between ${\tau}_o$ and water temperature (Y=-1.85X+21.9, $R^2=0.9868$, where Y is ${\tau}_o$ and X is temperature).

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.285-292
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• 2008

Data were taken from the dairy herd improve- ment program from the year 2000, composed of 10,929 first lactation cows consisting of 290,144 test-day records and 37,723 udder type records. The objective of the study was to estimate genetic and phenotypic correlation between fore udder attachment, rear udder height, rear udder width, udder cleft, udder depth, and somatic cell score (SCS) and to calculate heritability of udder depth, front teat length and SCS in Holstein cattle in Korea. The variance component estima- tion using test day model was determined by a derivative-free algorithm-restricted maximum likeli- hood(DF-REML) analysis method. Generally phenotypic correlations were very low between udder traits and lactation SCS which varied from －0.03 to －0.06. Heritability of all type traits and SCS was smaller than 0.12. The results of this study would be applicable to SCS using linear genetic evaluation for future studies.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.35-35
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• 2023

안정적인 유묘의 확보는 스마트작물생산을 위한 공정육묘 생산에서도 중요하며, 기내배양시 유전적 안정성이 높은 유묘의 대량증식은 유묘생산과 공정육묘생산에서 중요한 과정이다. 기내배양시 배양과 정에서 존재하는 체세포영양계변이(somaclonal variation)라는 장벽을 제거하는 것이 중요하다. 본 연구에서는 화본과 식물인 홍띠(Imperata cylindrica ‘Rubra’)로부터 기관분화 단계별 재분화체를 작성하여 기관분화 시 기내재생체의 유전적 안정성을 조사하였다. ISSR 마커에 기반하여 유전적 변이성을 조사하고자 7종류 총 21개체의 기관분화 단계별 재분화체 및 재분화식물체에 대하여 분석한 결과, 유전적 다형성은 기관분화 단계별 재분화체 및 순화 재분화체에서 대조구인 모식물체(1.4％) 대비 같거나 높게 나타나서 재분화체에서 유전적 안정성이 다소 낮은 것으로 나타났다. 또한, Jaccard 계수(Jaccard coefficient)로 총 21개체들 간의 유전적 유사도 지수를 평가한 결과, 유전적 유사도 지수는 0.747~1.0 사이에 분포하며, 평균 0.868로 나타났다. ISSR 마커 밴드에 기반하여 평균연결법(Average linkage method)으로 군집 분석한 결과, 모든 개체는 유사도 지수 0.809 ~ 1.000 내에 분포하였다. 유전적 유사도 지수 0.809에서 2개 그룹으로 유집되었으며, 모식물체와 실내재배, 노지재배 재분화 녹색 식물체가 같은 그룹으로 분류되었다. 이상의 결과는 화본과 식물의 기내배양에서 기관분화 시 존재하는 체세포영양계변이에 대한 기초 정보를 제공해 준다. 이들 기관분화에 따른 기내재생체의 안정성에 대한 연구자료는 향후 기내식물의 안정적인 대량번식에 있어 유익한 배경을 제공해 줄 것이다.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.739-748
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• 2003

The objective of this study was to estimate genetic parameters for test-day milk production and somatic cell score using field data collected by dairy herd improvement program in Korea. Random regression animal models were applied to estimate genetic variances for milk production and somatic cell score. Heritabilities for milk yields, fat percentage, protein percentage, solid-not-fat percentage, and somatic cell score from test day records of 5,796 first lactation Holstein cows were estimated by REML algorithm in single trait random regression test-day animal models. For these analyses, Legendre polynomial covariate function was applied to model the fixed effect of age-season, the additive genetic effect and the permanent environment effect as random. Homogeneous residual variance was assumed to be equal throughout lactation. Heritabilities as a function of time were calculated from the estimated curve parameters from univariate analyses. Heritability estimates for milk yields were in range of 0.13 to 0.29 throughout first lactation. Heritability estimates for fat percentage, protein percentage and solid-not-fat percentage were within 0.09 to 0.11, 0.12 to 0.19 and 0.17 to 0.23, respectively. For somatic cell score, heritabilities were within 0.02 to 0.04. Heritabilities for milk productions and somatic cell score were fluctuated by days in milk with comparing 305d milk production.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.680-693
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• 2011

In conceptual ecology, a concept does not exist independently but occupies an ecological niche in ecological environment. Among many biological concepts, genetic concepts are connected to several units including the genetics unit, and within the genetics unit the concepts of sub-areas are highly dependent on one another. For this reason, we analyzed conceptual diversity and conceptual proximity of genetic concepts through the ecological niche approach. For this purpose, we surveyed 995 9th graders. The areas covered in the survey were four genetic concepts: gene, chromosome, mitosis, and meiosis. The questionnaire presented biological concepts or terms related to each area, and the respondent marked the relevance between the presented biological concepts or terms and each area on a scale of 1~30 points. With 9th grade students, we analyzed the change of genetic concepts through class by the ecological niche approach. Through class, the total number of concepts increased in all of the areas, and the increase was smallest in the area of meiosis followed by mitosis, chromosome and gene. Relative density decreased with increases in the number of concepts. The conceptual diversity index also increased through class in all of the areas, and the increase was smallest in the area of meiosis followed by mitosis, chromosome and gene. In addition, difference in the relative density of concepts was reduced after class, and difference in the score of relevance was also reduced and consequently similarity among concepts increased. From these results were drawn conclusions as follows: First, through class, the conceptual diversity of genetic concepts increased. Second, through class, the conceptual proximity of genetic concepts increased.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.200-211
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• 1993

Somatic hybrids of Pleurotus florida ASI 2016 and Pleurotus ostreatus ASI 2018 were obtained by protoplast fusion. The 40 fusants($P1{\sim}P40$) was examined for the yield on fermented and pasteurized rice straw in a tray. The carpophore yield of them were showed as the range of $27.0{\sim}155.2$, based on parental values of 100(ASI 2018), The pilei of fusants between orange white colored P. florida and dark grey colored P. ostreatus had mixed colors in the young stage. Other breeding programmes were performed to improve new varieties with high yield and good quality. A new oyster mushroom variety, Wonhyeongneutaribeosus(P72), was developed at the Agricultural Sciences Institute, Rural Development Administration in 1990. This P.florida-ostreatus-ostreatus hybrid P72 was selected from 38 protoplast fusion products($P41{\sim}P78$) between P.florida-ostreatus recombinant P5-M 43-arg rib and P. ostreatus ASI 2-13-0 2001-19-pro orn. The yield indexes of 38 hybrids ranged $40.5{\sim}152.7$ compared with the parental values of 100(ASI 2001). Hybrid P72 was characterized by the large fruiting bundle of semispherical shape with long stipe and by the small and circular pileus, resulting in lower harvesting cost. A significant increase in carpophore production was observed in somatic hybrids of protoplasts due to heterosis. A comparision of hybrid with parents P72 was made using isozyme analysis. The esterase banding patterns could be characterized by new bands in the hybrids. Seven fusion products of four crosses between P.florida ASI 2016 and P. ostreatus ASI 2018 were analysed with respect to the distribution of progenies and segregation of gene markers by random basidiospore analysis. Segregation of alleles should yield progeny of four genotypes in a Mendelian ratio of 1 : 1 : 1 : 1 for prototrophs, auxotrophs of one parental type, auxotrophs of the other parental type, and auxotrophic recombinants, respectively. However, five fusants of them did not detect one parental, P.ostreatus, type. Basidiospores could yield progeny of 16 genotypes in the cross of one of the recombinant P5-M43-arg $rib{\times}P. ostreatus$ ASI 2-13-pro orn but the segregants of three fusants were not detected clearly. The allele ratio of loci could be expected 1 : 1 : 1 : 1 for arg, rib, pro and orn. The ratio, however, would be changed to 4 : 1 : 1 : 1 with increasing proportion of argo In almost all the fusants, prototrophic recombinants were recovered in large numbers against auxotrophic markers. Parental genotypes were recovered with the recombinant progeny amounting to $38.68{\sim}99.56%$. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.335-346
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• 2004

Factors associated with milk urea nitrogen on milk yield and milk composition were investigated in this study regarding feeding management and Physiological status of lactating cows. The data for 3 years between 1999 and 2002 for this study were collected from 129,645 cows by Korean Agricultural Cooperatives Federation. The objectives of this study were to describe the relationships between milk urea concentrations and seasonal factors, cow factors and production of milk, milk fat, protein and somatic cell score(SCS). Milk urea was highest in summer and it also showed a nonlinear association with milk yield. Milk yield was higher at milk urea concentrations of 21 ${\sim}$ 24mg/dl, however it decreased at higher level of milk urea concentrations than 24mg/dl. Milk urea was higher with increased parities of cows and in particular, at 3 to 4 parities. There was a negative association between milk urea and SCS in milk. SCS in milk was lowest at milk urea concentrations of 2l${\sim}$24mg/dl. Milk fat and milk protein were greatly affected by days in milk(DIM), year of birth, season and milk urea concentrations, respectively. While milk urea increased in summer, milk fat and protein were decreased. Milk protein decreased according to longer days in milk. With regard to the influences of parity, milk protein in overall was negatively correlated to milk urea in all lactations, however the extent of decrease of milk protein at high concentrations of milk urea was bigger at third lactation. The balanced supply of energy and protein to the animals might have greatly affected the urea concentrations and protein content of milk.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.517-524
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• 2004

The objective of this study was to investigate the environmental effects on duration time of milk flow, peak milk flow, and average milk flow in teats, and to estimate their relationships with milk yields in morning and evening milking, and to provide fimdamental information for the further study on their relationships with clinical mastitis and somatic cell in milk. A total of 6,768 milking records were studied in 72 Holstein cows. The influences of season, parity, lactation month, and milking interval on characteristics of milk flow considering in linear model were significant(p<.05). Duration of milk flow was longest at milking in fall, past first parity and second month of lactation, and with milking interval over than 13.5hrs. Average milk flow rate and peak milk flow rate were highest at milking in summer, past first parity and 8${\sim}$10 months of lactation, and with milking interval over than 13.5hrs. Milk flow rate was positively correlated to milk yield, and negatively correlated to the duration of milk flow. However duration milk flow was positively correlated to the milk yield with high level of correlation coefficient(+.60). For the establishment of optimum selection criteria on these traits, other aspects such as the udder health, disease and respective economic weights of milk flow characteristics in this study must be considered to develop the indices.

• Korean Journal of Plant Taxonomy
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• v.35 no.3
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• pp.161-174
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• 2005

In order to presume the relationships between two species of P. ternata and P. tripartia, and their populations of the Korean Pinellia, RAPD analysis was performed. The length of the amplified DNA fragments ranged from 300 to 2,500bp. Seventy scorable RAPD makers were found from the PCR reactions with 7 random oligoprimers and were analyzed by Nei-Li's genetic coefficient. Also, some regional groups instead of same taxa were clustered from the phenogram of UPGMA analysis and NJ tree. Populations within each species were clustered at low genetic distance, there had the closed relationship. According to the regional individuals, Pinellia ternata was showed the variation pattern of morphological (leaf shape and flower color) and cytological characters(somatic chromosome numbers). So we suggested to difference of characteristic variety based on variety of habitat. According to this study, new species (Pinellia sp.) was affiliated with Pinellia and had the closest relationship with Hallasan and Japan population. The RAPD data was very useful to define the genetic variation and to discuss the relationships among the intraspecific taxa and their populations of the Korean Pinellia.