• Journal of Embryo Transfer
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• v.29 no.3
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• pp.265-271
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• 2014

Implementation of smart embryo technologies in cattle e.g. ovum pick-up followed by in vitro embryo production (OPU-IVP). Seasonal variation is important factor for follicular growth, oocytes quality, quantity and developmental competence. Therefore the aim of present study was carried out to investigated whether the seasons (hot and cool) effect on follicular development, oocyte recovery and subsequent embryo development. Follicular oocytes were aspirated from Korean native cows (Hanwoo) by the ovum pick-up (OPU) method, which was performed 24 times during two different seasons, the hot (July to September) and cool (October to December), from OPU donors. The recovered oocytes were classified according to morphological categories and used for in vitro embryo production (IVEP). The mean number of total follicles was significantly higher (p<0.05) during the hot season ($18.32{\pm}2.26$) compared to cool season ($15.41{\pm}3.34$). Furthermore, seasons did not significantly effect on the number of oocytes recovered (hot season: 41.16% vs. cool season: 46.14%). However, the average number of Grade A oocytes was significantly greater during hot ($1.75{\pm}1.86$) season compared to the cool season ($1.00{\pm}1.46$), but there was no significant difference of other grades oocytes. The cleavage rate (hot: 66.67% vs. cool: 63.3%) and embryo development (hot: 58.95% vs. cool: 56.97%) did not differ significantly between the seasons. In conclusion, the results of present study suggest that the season (hot and cool) does not have effects on the oocyte recovery and embryo developmental competence of in vitro cultured embryos.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.193-199
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• 2002

This study was conducted to investigate the optimal physiologic mating time in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. We observed 32 cows that were devide into 4 parts of treatment : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months and 0.5kg daily gain). The first heat of treated cows was 263.3$\pm$6.4 days and average weight was 181.1$\pm$11.3kg. It was revealed the conception rates of first insemination were 25%(T1), 75%(T4) and number of insemination of T3 and T4(both 1.5) was lower than T1 and T2(2.3 and 2.4). In return of estrus after heifer's first parturition, they(T1, T2, T3 and T4) showed 66.2 days, 76.7 days, 62.4 days and 68.5 days respectively and the average was 65.7 days. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 was released just after 12 months. Only 5 cows (15.6%) in 32 were showed normal estrus cycle and ovulation before 12 months. Before and after parturition, P4 concentration was decreased fastly and then there was no detection of P4 from after parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results were summarized as that the optimal mating time of Hanwoo heifers was decided by the 14 months of age, 110 cm height and 265kg weight.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.583-593
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• 2015

This study was conducted to investigate the effects of mixed-sowing of legume forage and applying of cattle manure on the productivity of organic rye to provide dairy farmers with safe organic feeds. Also the present study aimed to evaluate optimal applying level of cattle manure and carrying capacity of Korean native cattle (Hanwoo) per unit area. The amount of crude protein was significantly higher in the mixed-sowing of legume forage (average 760~786 kg/ha) than in the single-sowing of rye (average 353 kg/ha) (p<0.05). The mixed-sowing of forage peas and the single-sowing of rye tended to improve by increasing the level of nitrous fertilization rather than the fertilization treatment. The amount of crude protein on the rye according to the mixed-sowing of legume was significantly higher in the mixture (average 8.29~9.90%) than in the single (average 4.93%) (p<0.05). The comparison by the level of nitrogen fertilization indicated significantly high for the rye in 50 kg N/ha than in fertilization treatments (p<0.05). Total digestible nutrients (TDN) amount in the single-sowing of rye was average 46.86% and has lower than average 49.96~50.12% of the mixed-sowing of legume, and especially the mixed-sowing of forage pea was the highest with 54.55% in 150 kg N/ha for the level of nitrogen fertilization (p<0.05). The breeding ability of annual organic livestocks per unit area according to the feed value of rye presented significantly higher ability in the mixed-sowing of legume (3.72~4.12 heads) than the single-sowing of rye (average 2.26 heads) (p<0.05). By summarizing above results, the mixed-sowing of legume is required to improve the productivity and the feed value of rye for increasing organic livestock breeding ability in southern area of Gyeongbuk regions, and the study for identifying the appropriate fertilization level using livestock excretions is further necessary.

• 한국해양학회지
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• v.27 no.3
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• pp.210-227
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• 1992

KODOS-89 area, the northwestern part of Clarion-Clarion-Clipperton fracture zones in the Northeast Pacific, was surveyed in order to study the occurrence and distribution of manganese nodules. Variations in the nodule characteristics are related mainly to seafloor topography. Nodules from abyssal plain have high Mn/Fe ratio and high Mn, Cu, Ni and Zn concentrations, whereas those from seamount are characterized by low Mn/Fe ratio and high Fe and Co concentrations. These compositional characteristics are attributed to toxic diagnosis and hydrogenesis, respectively. Nodules of the early diegenetic origin tend to accurate crystalline Mn-oxides uniformly within the topmost sediment layers and maintain a regular spheroidal, ellipsoidal to discoidal shape with rough surface textures. On the other hand, those of hydrogenetic origin are characterized by polynucleation, irregualr shape, and smooth surface textures. Nodule abundance is high (avg. 13.4 kg/m$^2$) in seamount area, resulting from ample supply of nucleating materials by auto-fragmentation of older nodules. Nodule abundance in abyssal plain is relatively low (avg. 3.9 kg/m$^2$) and tends to increase southward. This phenomenon results from facilitation of taking seed materials from adjacent seamount and enhancement of the early diagenesis by sufficient supply of organic materials. Nodule abundance is considered to be controlled primarily by seeding effects and secondly by supplies of organic materials.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.4
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• pp.255-264
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• 2003

A study was conducted to determine the effects of pig slurry application on forage yield and growth of fazing Hanwoo heifer in a mixed pasture. To each of three treatments 1.4ha were alloted a control applied with only chemical fertilizer (N-P-K=150-150-120kg/ha), two pig slurry lots applied with the amount to allow 100% (150 kg/ha) or 150% (225 kg/ha) of N used in the control. A randomized block design was used without replication. Cattle were allowed to graze continuously during the experimental period. Results obtained were as follows: Total dry matter yield was 16,291, 15,632 and 16,320 kg/ha for chemical fertilizer. pig slurry 100% and 150％, respectively. The pasture was dominated by perenial ryegrass during the first gazing season, but by orchard grass and perenial ryegrass (60∼70%) and red clover (20∼30%) during the second grazing season. Average gazing rate per ha was 2.75∼2.76 animal units and daily weight gain of grazing cattle was not different among treatments ranging from 0.563 to 0.580 kg. Total weight gain of grazing cattle per ha during the grazing period was 541, 541 abd 555 kg for chemical fertilizer, pig -slurry 100 and 150%, respectively. RBC, WBC, total protein and albumin etc. concentrations in blood were normal in all treatments.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.83-89
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• 2010

The objective of this study was to investigate the effect of the environmental and genetic factors on the carcass traits of Korean cattle. We have used the data of 22,954 Korean cattle slaughtered from 2005 to 2009 in Gyeongnam region and estimated the genetic parameters of 36,868 cattle including the pedigree individuals by means of EM-REML analytical method. In summary, the heritability of the carcass weight, eye muscle area, backfat thickness and marbling score was 0.39, 0.30, 0.33 and 0.62, respectively. The carcass weight and the eye muscle area showed high correlation between them with the genetic correlation of 0.86 and the phenotypic correlation of 0.72. The high heritability of marbling score is assumed to be the result of focusing the breed improvement on the quality of the meat. Through this study, it is considered that the Korean cattle in Gyeongnam region are improving, which will thus contribute to the increase of the farmer's income. Additional study on the economic trait must be carried out to obtain clearer results that will lead to further improvement of Korean cattle.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.331-336
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• 2018

The aim of the present study was to identify the metabolic changes that have occurred in Hanwoo Native Cow. Analysis of serum metabolites was carried out to investigate relationship of pregnancy rate and feeding systems. Totally, 281 cows were used for grazing and barn feeding. Grazing was carried out for 5 months in the pasture. In barn feeding, concentrate 3.0 Kg(TDN 68%, CP 14%) and rice straw 6 kg(TDN 50%, CP 6.5%) were fed. Artificial insemination(AI) carried out by timed AI procedure. The level of glucose(mg/dl), cholesterol(mg/mL), BUN(mg/dl), AST(U/l), ALT(U/l), and NEFA(uEq/l) were analyzed. In Table 1, barn feeding with 120% group was showed high Cholesterol and BUN levels compared those with 80% feeding group(p<0.05). In Table 2, 60 pregnant cows in grazing herd showed low Cholesterol, AST and NEFA levels compared to 43 non-pregnant cows($149.8{\pm}4.9$, $99.1{\pm}2.6$, $326.7{\pm}15.7$ vs. $165.9{\pm}4.6$, $108.9{\pm}3.2$, $419.2{\pm}32.8$, respectively, p<0.05). In Table 3, 126 grazing feeding cows showed high Glucose, Cholesterol, AST, ALT, and NEFA levels compared to 22 barn feeding cows($84.8{\pm}1.3$, $142.5{\pm}2.5$, $97.7{\pm}2.3$, $34.3{\pm}0.5$, $317.8{\pm}13.6$ vs. $56.0{\pm}1.3$, $128.9{\pm}4.6$, $80.9{\pm}2.0$, $27.1{\pm}0.9$, $160.2{\pm}18.9$, respectively, p<0.05). Further study needed to obtain more accurate level of metabolites in serum for pregnant and non-pregnant cows.

• Journal of Practical Agriculture & Fisheries Research
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• v.6 no.1
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• pp.102-115
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• 2004

Main objectives of this study were to increase digestibilities of indigestible ingredients in spent mushroom composts (SMC) consisted of sawdust mainly as well as to fortify conversion of inorganic Se present in SMC to organic Se via fermentable microbial actions. Experimental feeds were designed to contain the increasing level of selenium (0.06ppm, 0.54ppm, 1.26ppm and 1.86ppm) in combination with SMCs of Se-enriched and non-Se mushrooms. Feeds were also fermented using commercial microbial feed additives (Sambae, Ltd., Korea) comprised Saccharomyces, Bacillus, Aspergillus, Streptococcus and Actinomycetes before feeding trial for Hanwoo (Korean native cattle). Those were fermented for 0, 12, 24, and 48 hrs. Initial pH was linearly increased as Se concentration increases or the proportion of SMC of Se-enriched mushroom increased (p<0.0001). pH values of fermented feeds (0.54ppm, 1.26ppm and 1.86ppm) containing SMC of Se-enriched mushroom were not different since 12 hrs of fermentation time and their pH was significantly lowered compared to control group. The increasing level of Se concentration in fermented feeds showed significant differences in organic and inorganic Se contents and proportion of organic Se among treatments. As a SMC proportion of Se-enriched mushrooms in the fermented feed was increased, organic Se proportion was significantly decreased (p<0.0001). The control treatment (0.06ppm) comprising the non-Se SMC only was estimated of the organic Se to be 100% and the treatment groups containing the increasing level of Se were estimated of organic Se to be approximately 70%.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.110-118
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• 2002

This study was conducted to investigate the physiology of optimal reproductive age in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. Thirty two cows were devided into 4 groups of treatments : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months of age and 0.5kg daily gain). The days of the first heat of treated cows were 263.3±6.4 days and average weight was 181.1±11.3kg. The conception rates of first insemination were 25%(T1) and 75%(T4), and the number of insemination of T3 and T4(both 1.5) was lower than those of T1 and T2(2.3 and 2.4), respectively. With regard to estrus return after the first parturition, T1, T2, T3 and T4 showed 66.2,76.7, 62.4 and 68.5 days, respectively, indicating the average days of estrus return was 65.7. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 began to be detected after 12months. Only 5(15.6%) out of 32cows showed normal estrus cycle and ovulation before 12 months. During the peri-parturition period, P4 concentration was rapidly decreased and there was no detection of P4 from parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results imply that the optimal reproductive age of Hanwoo heifers would be around at the 14 months of age, 110cm height and 265kg weight.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.365-373
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• 2000

The purpose of this study was to investigate the effects of the fusion pulses and fusion media on fusion rate and the development of embryos produced by somatic cell nuclear transfer in Hanwoo (Korean cattle). Nuclear donor cumulus and fetal fibroblast cells were cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum at 38.5$^{\circ}C$ in a humidified atmosphere of 5% $CO_2$in air. The in vitro matured oocytes were enucleated and then the isolated donor cells were introduced. The cumulus cell and cytoplast were fused using one pulse of 70 volts for 40$mutextrm{s}$, two pulses of 70 volts for 40$mutextrm{s}$ and one pulse of 180 volts for 15$mutextrm{s}$. The fetal fibroblast cell and cytoplast were fused using one pulse of 180 volts for 15$mutextrm{s}$ or 30$mutextrm{s}$. The cumulus cell and cytoplast were fused using mannitol and Zimmerman cell fusion medium (ZCFM) as a fusion medium. The fused embryos were activated after the fusion with 10 $\mu$M calcium ionophore for 5 min and 2 mM 6-dimethyl- aminopurine for 3 h. The nuclear transfer embryos were cultured in 500 ${mu}ell$ well of modified CR1aa supplemented with 3 mg/$m\ell$ BSA in th $\varepsilon$ four well dish cove red with mineral oil. After 3 days culture, culture medium was changed into modified CRlaa medium containing 1.5 mg/$m\ell$ BSA and 5% FBS for 4 days. The incubation environment was 5% $CO_2$, 5% $O_2$, 90% $N_2$ at 38.5$^{\circ}C$. When the cumulus cells were fused with enucleated oocytes by three different fusion pulses, one pulse of 180 volts for 15 $mutextrm{s}$ yielded the highest fusion rate and developmental rate to blastocyst among the pulses (P＜0.05). When the fetal fibroblast cells were fused with enucleated oocytes, one pulse of 180 volts for 30$mutextrm{s}$ yielded significantly higher fusion rate compared with that for 15 $mutextrm{s}$(P＜0.05). The present result indicates that the fusion rate between karyoplast and cytoplast was affected by the cell type and the optimal fusion condition was different according to cell type or size. When the fusion was conducted by the use of mannitol and ZCFM, the fusion rate was 71.2% and 65.8%, respectively. The developmental rates to blastocyst were 37.8% and 39.8%, respectively. There was no significant difference between two fusion media in the developmental rate of cumulus cell nuclear transfer embryos. These results indicate that optimal electric current should be selected according to cell type.