• Journal of Embryo Transfer
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• v.9 no.2
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• pp.145-152
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• 1994

The suitable electric stimulation is essential for activation and fusion of oocytes before or after nuclear transplantation The present study was undertaken to determine the optirnal condition for the parthenogenetic activation of in vitro rnatured(IVM) bovine oocytes by electric stimulation. Different direct current(DC) electric voltage of 1.0, 1.5 and 2.0 kV/cm and pulse duration of 30, 60 and 120 $\mu$sec were applied to the JVM nocytes in 0.3 M mannitol solution containing each 100 $\mu$M CaCl$_2$ and MgCl$_2$. IVM occytes at 24, 28 and 32 hours Post-maturation(hpm) were also electrically stimulated at 1.5 kV /cm, for 60 $\mu$ sec. The stimulated nocytes were then co-cultured in TCM-199 solution containing 10% fetal calf serum with bovine oviductal epithelial cells for 7~9 days in a 5% $CO_2$ incubator at 39$^{\circ}C$ ~ Their activation and in vitro development to morula and blastocyst were assessed under an inverted microscope. The higher activation rates 62.8 and 63.4% and in vitro de- velopment rates to morula and blastocyst 5.1 and 10.9% were shown in the oocytes stimulated at the voltage of 1.0 and 1.5 kV/cm than 2.0 kV/cm, respectively. No signifi- cantly(P<0.05) different activation rate was shown in JVM oocytes stimulated for 30, 60 and 120 $\mu$sec, but developmental rates to morula and blastocyst was significantly(P<0.05) higher in the oocytes stimulated for 30 $\mu$sec(6~3%) and 60 $\mu$sec(10~0%) than 120 $\mu$sec(0~ 0%). The aged oocytes at 28 and 30 hpm showed significantly(P<0.05) higher activation rates(72~7 and 79.7%) than the oocytes at 24 hpm(50~9%)~ Also, their developmental rates to morula and blastocyst were significantly(P<0.05) higher in the nocytes at 28(14.3%) and 32 hpm(15.9%) than 24 hpm(3.6%). From these results, it can be suggested that the optimal electric stimulation for IVM bovine occytes is a DC voltage between 1.0 and 1.5 kV/cm, pulse duration of 30 or 60 $\mu$sec, and the optimal age of IVM oocytes for electric activation is at 32 hpm.

• Journal of Embryo Transfer
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• v.11 no.1
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• pp.15-26
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• 1996

This study was conducted to improve the in vitro maturation(JVM), in vitro fertilization (IVF) and in vitro developmental capacity of oocytes derived from slaughtered Korean native cattle. The recoverd oocytes, obtained from a local slaughter house, were used completely surrounded by at least 3 layers of cumulus cells in combination with a homogeneous cytoplasmic pigmentation. In vitro maturation was induced in TCM-199 or Ham's F-10 supplemented with LH(1O $\mu$g/rnl), FSH(35 $\mu$g/ml), estradiol-17$\beta$(1 $\mu$g/ml) at 39$^{\circ}C$ under 5% $CO_2$ in air for 24 hours. Sperm from caudal epididyrnis and previously matured cumulus-oocytes complexes were cultured for 24 hours in 100 $\mu$l droplets of fertilization media under paraffin oil. The zygotes were cultured with media(TCM-199 with bovine oviductal epithelial cells or CRlaa) for 7 to 10 days. The cleavage rate of IVM-IVF oocytes was significantly (P<0.05) higher following maturation using Ham's F-10 (59.9%) than TCM-199 (51.6%). Development to the blastocysts among cleaved embryos was not signficantly different between maturation media: Ham's F-10 (16.0%) and TCM-199(11.9%). However, the hatching rate was affected significantly (P<0.05) on rnaturation media as 62.9% in Ham's F-10, compared with 41.2% in TCM-199. The cleavage rate of IVM-IVF oocytes was significantly (P<0.05) higher following IVF using m-TALP medium (80.1%) than BO medium (51.6%). The percentage of in vitro developed blastocysts among cleaved embryos was not signficantly different between fertimization media: BO (11.7%) and m-TALP (17.6%). The cleavage and the developmental rate to the blastocysts after IVF in m-TALP or condition medium(CM) with or without oviduct epithelial cell monolayer(OECM) was similar(80.1% and 17.6% in m-TALP, 83.8% and 19.4% in M-TALP with OECM. 82.9% and 18.9% in CM, 87.6% and 16.0% in CM with OECM, respectively). The percentage of in vitro developed blastocysts among cleaved embryos was significantly (P<0.05) higher in TCM-199 medium co-cul tured with bovine oviduatal epithelial cell monolayers(35.2%) than CRlaa medium(1.9%). These results stggest that the most transferable IVF embryos could be produced from Ham's F-10, m-TALP and TCM-199 medium with bovine oviductal epithelial cell monolayers for IVM, IVF and IVC, respectively.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.604-609
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• 2008

Analyses were conducted to estimate carcass component of yield grade factors by sex and live weight class and to develop the prediction equation of retail product weight by sex in Korean native cattle (Hanwoo). Data from 42,113 Hanwoo carcasses were used to estimate the traits of yield grade factor and an additional 1,066 carcasses were used to develop the prediction equation of retail meat weight. The average of fasting weight of cow, bull and steer were 529 kg, 596 kg, and 634 kg respectively. Carcass weight (CW), backfat thickness (BFT), loineye area (REA), Index score of wholesale meat and yield grade were significantly (p<0.01) affected by sex and live weight. The lean meat percentage, fat percentage and bone percentage based on the weight of cold carcasses were significantly different (p<0.05) between sex groups. The equation of predicting the retail meat product from this study could be expressed as a multiple regression $Y=-4.18+0.63{\times}CW\;(kg)-0.17{\times}BFT\;(cm)+0.16{\times}REA\;(cm^2)$, $R^2=0.93$. Among the independent factors, the BFT was the highest contributor to the prediction equation. Using the equation from this study should allow for rapid, precise and cost-effective assessment of the retail product in Hanwoo beef carcasses.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.667-672
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• 2011

This study was carried out to increase the breeding rate using sustained recombinant bovine somatotropin (bST) and examine the reproductive disorder and disease prevalencies of cow and calf, respectively. Sixty cows were allotted randomly to three groups in randomized complete block design; (1) No treatment, (2) 500 mg bST two times + 250 mg bST SC injection five times from 3 weeks before to 9 weeks after parturition every two weeks, (3) 500 mg bST two times before 3 weeks parturition + 250 mg bST SC injection three times from five to 9 weeks after parturition every two weeks. Developmental data of birth weight, weaning weight, total gain and average daily gain in control was $22.9{\mu}0.45$ kg, $88.0{\mu}1.13$ kg, $65.1{\mu}0.74$ kg and $0.54{\mu}0.08$ kg, respectively. There is no significant difference between Group 1 and 3 in the examined factors. However, there is significant difference between Group 1 and 2 in the birth weight ($24.4{\mu}0.88$ kg), weaning weight ($101.0{\mu}1.77$ kg), total gain ($76.7{\mu}0.9$ kg) and average daily gain ($76.7{\mu}0.9$ kg). Total gain was showed higher in Group 2 and 3 than Group 1 in the >2nd parity, and in Group 2 than Group 1 and 3 in the 1st parity. There is no significant difference in the BCS, no return days and disease occurrence of cow and calf by bST treatment. Number of service per conception was slightly increased in the Group 3 compared to Group 1 and 2. To increase the breeding ability of Hanwoo, it is recommended that 500 mg bST two times + 250 mg bST injection five times from 3 weeks before to 9 weeks after parturition every two weeks.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.65-71
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• 2017

The elevated temperature and high humidity has been known as main reason for heat stress on animals and cause detrimental effects on productivity of organisms and physiological conditions of normal bioactivities. The aims of this study were to evaluate the relationship between time of heat shock simulation during in vitro maturation and developmental competence of subsequent embryo after in vitro fertilization. Heat shocked cumulus-oocyte complexes (COCs) of Korean native cattle were subjected to normal conditions for 22, 21, 18 and 12 h respectively and transferred to heat stress inducing condition at $40.5^{\circ}C$ in other incubator for 0 (control), 1 and 4 h. After maturation for 22 h, the oocytes were fertilized and cultured in mSOF media for 8 d and examined the developmental capacity of embryos. There were no differences in maturation and cleavage rates between 0, 1 and 4 h heat socked oocytes, but blastocysts formation were lower in the 4 h heat stressed oocytes. The apoptotic cells of developed blastocysts were also increased in at day 8 with 4 h heat shocked oocytes. These results indicate that heat shock on oocytes during maturation could cause negative effects on the developmental competence of embryos.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.269-277
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• 1995

This experiment was conducted to study on forage utility of native grasses in polderland for salt tolerance plant selection and good feed with collection and evaluation. As the result of investgate, it was carried out feed evaluation, germination physiology and early growth at the different salt content of Puccinellia coreesis Honda and P. nipponica Ohwi from May 1993 to June 1994. Germination physiology of the grasses was light and low temperature favored optimum germination temperature was 1$0^{\circ}C$, germination period was 30 days. Dormancy awakening was needed wet and high temperature condition with 1~3 days storage. Germination rate increased 18.0% of P. coreensis and 39.0% of P. nipponica than those of non treatments. Early growth condition of different salt content was good also at in 1.00% and 0.50% levels of P. coreensis and P. nipponica. Crude protein content was 8.4% at P. coreensis, 7.1% at P. nipponica and 10.3% of Italian ryegrass, and NFE content was arrangement in order of P. coreensis, Italian ryegrass and P. nipponica. TDN content was not different between P. coreensis, P. nipponica and Italian ryegrass. Also P. coreensis and P. nipponica have a good taste for cattle as same as other crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.263-268
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• 2009

This study was conducted to determine application possibility of mulberry (Morus alba) silage as a functional feed in feeding management of Korean native cattle for high quality beef production by analysing active components and antioxidative activity. The chemical analysis of mulberry silage indicates that the content of dry matter, crude protein, ether extract, crude fiber and crude ash was $28.41{\pm}3.12%,\;12.43{\pm}0.28%,\;2.47{\pm}0.18%,\;20.29{\pm}0.75%\;and\;6.98{\pm}0.12%$, respectively. The content of 1-deoxynojirimycin (1-DNJ), which is representative active ingredient of mulberry and blood sugar descending component, was 0.568 mg/g and the content of $\gamma$-Aminobutyric acid (GABA), which is blood pressure descending component, was 5,936.22 pmol. Mulberry silage used in this study did not contain flavonoids but did contain total phenols for 21.69 ${\mu}g/mg$. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was increased with increasing the concentration of mulberry silage extracts and there was above 50% of scavenging activity at the concentration of 0.25 mg/ml. Hydroxyl radical scavenging activity was also increased with increasing the concentration of silage extracts. Alkyl radical scavenging activity was high at the low concentration of silage extracts, which was above 50% of scavenging activity at the concentration of 0.125 mg/ml. The result of this study indicated that there was high possibility of mulberry silage as a functional feed for beef cattle.

• Journal of Animal Science and Technology
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• v.55 no.1
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• pp.13-18
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• 2013

This study was conducted to estimate the Genomic Estimated Breeding Value (GEBV) using Genomic Best Linear Unbiased Prediction (GBLUP) method in Hanwoo (Korean native cattle) population. The result is expected to adapt genomic selection onto the national Hanwoo evaluation system. Carcass weight (CW), eye muscle area (EMA), backfat thickness (BT), and marbling score (MS) were investigated in 552 Hanwoo progeny-tested steers at Livestock Improvement Main Center. Animals were genotyped with Illumina BovineHD BeadChip (777K SNPs). For statistical analysis, Genetic Relationship Matrix (GRM) was formulated on the basis of genotypes and the accuracy of GEBV was estimated with 10-fold Cross-validation method. The accuracies estimated with cross-validation method were between 0.915~0.957. In 534 progeny-tested steers, the maximum difference of GEBV accuracy compared to conventional EBV for CW, EMA, BT, and MS traits were 9.56%, 5.78%, 5.78%, and 4.18% respectively. In 3,674 pedigree traced bulls, maximum increased difference of GEBV for CW, EMA, BT, and MS traits were increased as 13.54%, 6.50%, 6.50%, and 4.31% respectively. This showed that the implementation of genomic pre-selection for candidate calves to test on meat production traits could improve the genetic gain by increasing accuracy and reducing generation interval in Hanwoo genetic evaluation system to select proven bulls.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.4
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• pp.499-505
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• 2011

The purpose of this research was to study the characteristics of Hanwoo (Korean native cattle) beef fed without mugwort (T0) and Hanwoo beef fed with mugwort (T1) during storage at$3{\pm}1^{\circ}C$ for 50 days. During cold storage, $a^*$ and $b^*$ value of meat color for T1 decreased slowly compared to those of T0, there was significant difference between T0 and T1 after 40 days (p<0.01). The shear force value of T0 and T1 decreased (p<0.001), and the drip loss and cooking loss of T0 and T1 increased (p<0.05). However, there was no significant difference between T0 and T1. During refrigeration period, the volatile basic nitrogen contents of T1 slowly increased compared to T0, there was significant difference between T0 and T1 after 50 days (p<0.01). The total plat count and thiobarbituric acid value of T1 slowly increased compared to T0, and there was significant difference between T0 and T1 after 30 days (p<0.01). Further, the decrease of the antioxidant activity of T1 was delayed, there was significant difference between T0 and T1 after 40 days (p<0.05). There was no significant difference of taste, juiciness, or tenderness of cooked meat between T0 and T1. The aroma and palatability of cooked meat for T1 fed with mugwort were significantly superior than those of T0 at day 30 after storage (p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1202-1208
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• 2020

Objective: The aim of this study was to identify a distribution pattern of meat quality grade (MQG) as a function of carcass yield index (CYI) and the gender of Hanwoo (bull, cow, and steer) to determine the optimum point between both yield and quality. We also attempted to identify how pre- and post-deboning variables affect the gender-specific beef quality of Hanwoo. Methods: A total of 31 deboning variables, consisting of 7 pre-deboning and 24 post-deboning variables from bulls (n = 139), cows (n = 69), and steers (n = 153), were obtained from the National Institute of Animal Science (NIAS) in South Korea. The database was reconstructed to be suitable for a statistical significance test between the CYI and the MQG as well as classification of meat quality. Discriminant function analysis was used for classifying MQG using the deboning parameters of Hanwoo by gender. Results: The means of CYI according to 1+, 1, 2, and 3 of MQG were 68.64±2.02, 68.85±1.94, 68.62±5.88, and 70.99±3.32, respectively. High carcass yield correlated with low-quality grade, while high-quality meat most frequently was obtained from steers. The classification ability of pre-deboning parameters was higher than that of post-deboning parameters. Moisture and the shear force were the common significant parameters in all discriminant functions having a classification accuracy of 80.6%, 71%, and 56.9% for the bull, cow, and steer, respectively. Conclusion: This study provides basic information for predicting the meat quality by gender using pre-deboning variables consistent with the actual grading index.