• Journal of Embryo Transfer
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• v.21 no.3
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• pp.183-190
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• 2006

These studies were conducted to monitor developmental competence of follicular oocytes collected from the carcass of the high meat quality in Korean native cattle using each individual protocol of IVM, IVF and IVC. The follicular oocytes that were collected from the ovaries of the cow yielded 1, $1^+\;and\;1^{++}$ meat quality were matured, fertilized and cultured using each individual protocol of IVM, IVF and IVC. As results, the number of follicular oocytes collected from individual fundamentally-registered cows yielded 1, $1^+\;and\;1^{++}$ meat grade were 28.9, 28.8 and 29.6 per head, respectively. The rates of blastocyst formation after IVM, IVF and IVC were 27.2, 28.7 and 32.9% in the cows yielded 1, $1^+\;and\;1^{++}$ meat quality, respectively. The rate of blastocyst formation was 8.4 per head. The number of follicular oocytes collected from pedigree registered cows yielded 1, $1^+\;and\;1^{++}$ meat quality were 25.8, 27.1 and 27.0 per head, respectively. The rates of blastocyst formation were 23.0, 33.7 and 42.6% in the meat quality of 1, $1^+\;and\;1^{++}$ after in vitro-manipulation, respectively (p<0.05). The rate of blastocyst formation was 8.5 per head. In conclusion, these results suggest that in vitro embryo production system using individual culture system including IVM, IVF and IVC can make good use of the gene from the carcass of the high meat quality in Korean native cattle.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.260-265
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• 2007

This study was carried out to investigate the effect of Electron Beam irradiation on physico-chemical characteristics of Hanwoo meat. A total of sir beef carcasses $(280{\sim}300\;kg)$ that were quality grade $1^+$(marbling score No. 7, meat color No. 4, maturity No. 1, texture No. 1) was purchased at the commercial slaughter house. The carcasses were transported and washed using high pressure water, and pasteurized with 50% ethyl alcohol in the laboratory. After the carcasses were deboned and trimmed, loin and round were taken out to make steak (1.5 cm thickness) or patty respectively. Samples were wrap or vacuum packaged and irradiated with 0, 3, 4.5, 6 and 7.5 kGy using electron-beam accelerator. Irradiated samples were used to measure pH, moisture, crude protein, crude fat, and meat color. There was no significant (p>0.05) difference in pH between vacuum packaged (VP) and wrap packaged (WP) treatment, and the pH was not changed by electron-beam irradiation levels. Both control and irradiated treatments of steak showed higher tendency in moisture content. In crude protein content, control was higher than irradiated treatment in steak, but there were no difference in patty. Lightness ($L^{\ast}$) of meat color has no difference between irradiated and non-irradiated treatment (p>0.05). The value of redness and Yellowness of meat was dropped by increasing irradiation (p<0.05), but there was no difference between control and 3 kGy treatment (p<0.05).

• Korean Journal of Organic Agriculture
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• v.18 no.3
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• pp.419-432
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• 2010

This study was conducted to determine effects of applying cattle slurry and mixed sowing with legumes such as hairy vetch or forage pea on productivity, feed values and organic stock carrying capacity of whole crop barley and rye as winter forage crops, and to obtain organic forages together with higher soil fertility. Experimental plots consisted of 7 treatments, which were non-fertilizer, chemical fertilizer (containing phosphate and potassium: P+K), chemical fertilizer (containing nitrogen, phosphate and potassium: N+P+K), organic fertilizer, cattle slurry, cattle slurry application (mixture with hairy vetch), and cattle slurry application (mixture with forage pea) plots. Each treatment was triplicates, and seven treatments were allocated in a completely randomized block design. For whole crop barley or its mixture crops, annual dry matter (DM), crude protein (CP), and total digestible nutrients (TDN) yields of N+P+K plots were significantly (P<0.05) higher than other plots except for cattle slurry plots. The CP content of barley or its mixture crops was significantly higher tor N+P+K plot (9.8%) and mixture plots with legumes (8.6~9.7%) than those of other treatments. As 450 kg Hanwoo heifers were fed diets included 70% whole crop barley or 70% mixture crops with legumes, mixture plots are capable of raising average 1.7 to 1.8 heads/ha a year. For rye or its mixture crops, annual DM, CP, and TDN yields represented 6.9~7.1, 0.5~0.6 and 4.3~4.4 ton/ha, respectively. The N+P+K plot contained 10.8% CP, which was higher (P<0.05) than all other treatments. In case of 450 kg Hanwoo heifers fed diets included 70% rye or 70% mixture crops with legumes, mixture plots can rear average 1.9 heads/ha a year. When it was considered based on crop yields and organic stock carrying capacity, applying cattle slurry to whole crop barley or rye had the comparable yields and feed values to chemical fertilizer application. Moreover, whole crop barley and rye within cattle slurry plots had a greater combination with hairy vetch and forage pea, respectively, and their mixture crops with legumes had higher crude protein and TDN yields within cattle slurry plots. In conclusion, it would be expected that mixed sowing with legumes in the application of cattle slurry to grass crops could be substituted for imported organic grains as dietary protein sources in feeding organic livestock.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.191-200
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• 2002

This study was conducted to estimate the effects of environmental factors on certain reproductive traits in Korean cattle on the basis of data from Korean Cattle Improvement Areas which were surveyed from 1986 to 1995. Results obtained were summarized as follows ; 1. Least square means of the reproductive traits estimated were 466.11${\pm}$5.72 days for age at 1st service, 480.10${\pm}$6.15 days for age at 1st conception, 742.79${\pm}$7.48 days for age at 1st calving, 64.97${\pm}$1.42 days for days at 1st service postpartum, 72.06${\pm}$1.73 days for days open, 355.93${\pm}$1.92days for calving interval, 285.38${\pm}$0.42 days for gestation length and 1.21${\pm}$0.02 days for number of services for conception, respectively. 2. The ranges of the least squares means for the districts were 447.62${\pm}$5.94-490.72${\pm}$5.94 days for age at 1st service, 464.27${\pm}$6.38-505.20${\pm}$6.39 days for age at 1st conception, 721.91${\pm}$7.85-772.75${\pm}$7.80 days for age at 1st calving, 62.27${\pm}$1.55-68.97${\pm}$1.74days for days at 1st service postpartum, 69.74${\pm}$1.97-74.36${\pm}$2.27days for days open, 352.71${\pm}$2.18-359.64${\pm}$2.09 days for calving interval, 284.52${\pm}$0.42-286.04${\pm}$0.47days for gestation length and 1.11${\pm}$0.02-1.30${\pm}$0.02 days for number of services for conception, respectively. 3. Age at 1st service was latest in the cows with Basic Register and tended to be earlier for the more advanced registers. The number of services per conception tended to increase for the more advanced registers. 4. Days at 1st service postpartum was longest in the 2nd parity and tended to be shorter with the advancement of parity. The number of services per conception tended to decrease with the advancement of parity. 5. As the calving year advances from 1987 to 1995, days at 1st service postpartum, days open and calving interval tended to be longer, and number of service per conception tended to increase. 6. Days at 1st service postpartum, days open and calving interval were shorter in the cows that calved in spring and summer than in the cows that calved in fall and winter. The number of services per conception was larger in the cows that cocalved in fall and winter than the cows that calved in spring and summer.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.1-10
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• 2004

These studies were carried out to improve the reproductive efficiency through embryos transfer of Hanwoo IVM/IVF embryos. Following routine IVM/IVF procedure, oocytes and zygotes were cultured far 40 to 44 h in CRlaa medium with BSA. Then 2 to 8-cell embryos were removed the cumulus cell and were cultured in CRlaa medium containing 10% fatal bovine serum and 2.5 mM taurine in 5% $O_2$ and 5% $CO_2$ at 38.5$^{\circ}C$. The fresh embryos of the morulae and blastocysts cultured for 6 to 9 days in vitro or the frozen-thawed embryos were transferred into recipients. The pregnancy rates of the blastocyst produced for 6, 7, 8, and 9 days in vitro culture were 59.4, 68.2, 66.0 and 100%, respectively. In the developmental stage, pregnacy rates of early blastocysts (61.1%), blastocysts(64.7%) and expanded blastocysts(69.5%) were higher than that of morulae stage(20.0%). The pregnancy rates according to the corpus luteum grades of A, B and C in recipients were 73.6, 62.9 and 50.0%, respectively. Effects of donor-recipients synchrony of after day 2, 1 and 0, before day 1 and 2 on the pregnancy rates were 35.7, 65.5, 72.6, 67.9 and 60.0%, respectively. Pregnancy rates of the body condition score of recipients $\leq$2(71.3%) were higher than those of $\geq$3.0 score(40.0%). The pregnancy rates according to the parity of recipients when embryo was transferred to cow(70.6%) was higher than in heifer(59.1%). The pregnancy rates according to hormone treatment before embryo transfer were 69.9% in hCG + GnRH administration group and 63.0% in control group. Fresh and frozen-thawed embryos on the pregnancy rates were 70.6 and 36.4%, respectively. Pregnancy rates in single and AI+single was 90.0% and 64.8%. Pregnancy rates in twin induction was better than in single. These results indicate that pregnancy rates after transfer were affected on the embryo ages, donor-recipient synchrony, body condition score of recipients, corpus luteum status, parity and hormone treatment to recipients.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.742-748
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• 2009

In the meat industry, correct breed information in food labeling is required to assure meat quality. Genetic markers provide corroborating evidence to identify breed. We described the development of DNA markers to discriminate between Korean beef cattle (Hanwoo), Holstein, and mixed cow beefs. As most breeds are standardized for coat colour, the melanocortin 1 receptor (MC1R) gene, involved in the regulation of eu/pheomelanins synthesis, has been suggested as marker for breed traceability of products of animal origin. We also designed sex-determining region Y (SRY) gene specific primers for Y chromosome detection. In this study, fragments of MC1R gene and SRY gene were amplified by multiplex-PCR and subjected to digestion by MspA1I restriction endonuclease. Reaction products were analysised by denaturing high performance liquid chromatography (DHPLC). As a result, we identified 6 DHPLC peak types from MC1R gene and SRY gene analysis. DHPLC method showed more sensitive than RFLP method for DNA fragments analysis. Therefore, DHPLC method can apply to identify for Hanwoo, Holstein and mixed beef.

• 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.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.833-840
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• 2004

The current study was conducted to analysis the effects of sex and live weight on carcass characteristics using total 773 Hanwoo, and to assess the effects of quality grade on chemico-physical and sensory characteristics in longissimus muscle. Results show that both steer and cow received superior quality grade to bull within the same weight c1ass(P < 0.05). Marbling score, texture, maturity, meat color and fat color were significantly( P< 0.01) affected by sex, whilst only marbling score and maturity were significantly affected by live weight. The ultimate quality grade showed significant relationships with marbling score(r = - $0.81^{**}) meat color (r= 0.21^{**}) fat color(r = 0.10^{**}) and with texture(r = 0.41^{**})$ but that had no such a relationship with maturity. WB-shear force and cooking loss were decreased when carcass grade was increased(P < 0.01), but water-holding capacity was identical between the quality grades. Objective meat color dimensions in lightness, redness and yellowness were increased for higher quality grade(P< 0.01). Meat flavor, juiciness and tenderness received higher scores for higher quality grade(P< 0.01). Intramuscular fat content had significantly relationships with WB-shear force(r = 0.$56^*), water-holding capacity(r = 0.18^{**}), juiciness(r = 0.46^{**}), tenderness(r= 0.49^{**})$, and flavor intensity(r = 0.$34^*$). In addition, a higher WB-shear force was related to a lower flavor, tenderness and juiciness scores.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.72-81
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• 1981

This study was conducted to determine the differences in the growth and milk production performance of Holstein Crossbreds (Korean Native Cattle(♀)${\times}$Holstein(♂)) and Korean Native Cattle produced at the Livestock Experiment Station of the Office of Rural Developement from 1973 to 1978. The number of heifers and cows used in this experiment were 15 head of Korean Native Cattle and 11 head pf Holstein Crossbreds Cattle. Body weight and body measurements were taken at birth, 6, 12, 24 and 36 months of age, however, body measurements were not taken at birth. Milk production was checked from the 11 th day to 180th day after calving. The data was analyzed using the least square procedure in order to estimate the effect of the mating group, year of birth, calving season and parity. The results obtained from this study were as follows: 1. The body weights of the Holstein Crossbreds were heavier than the body weights of purebred Korean Native Cattle. The body weight of the Holstein Crossbreds averaged 28.09kg, 146.64kg, 254.48kg, 392.04kg and 454.46kg at birth, 6, 12, 24 and 36 months of age, respectively. However, the body weights of purebreds Korean Native Cattle averaged 22.45kg, 132.82kg, 220.68kg, 363.54kg and 365.54kg at the same ages. 2. The year of birth affected on body weight at each point during the growing stage, except birth, heifers born in the spring and autumn were heavier than the others, but calving season did not affect on body weight during the growing stage except at birth and 6 months. 3. Parity showed significant differences on body weight in the growing stage. Calves from the 5th parity had a tendency to be heavier than the other calves. 4. The year of birth, calving season and parity at calving had no affect on the change of body measurements, but the wither height, hip height, chest depth, chest girth and hip width were significantly greater in the Holstein Crossbreds at 24 months of age. 5. Mating groups had a significant affect on milk production during the growing stage. Year of birth and calving season did not affect milk production, but parity was significant from 11 days after calving. 6. The least-squares means used to determine the daily milk production were 3.60 and 8.26kg/day for Korean Native Cattle and the Holstein Crossbreds, respectively.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.840-846
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• 2005

This study was carried out to investigate the effect of electron beam irradiation and cooking temperature on physico-chemical characteristics and lipid oxidation of beef. A total of six beef carcasses ($280\∼300 kg$) that were quality grade $1^{+}$(marbling score No.7, meat color No.4, maturity No.1, texture No.1) was purchased at the commercial slaughter house. The carcasses were transported and washed using high pressure water, and pasteulized with $ 50\% $ ethyl alcohol in the laboratory. After the carcasses were deboned and trimmed, loin and round were taken out to make steak (1.5cm thickness) or ground beef respectively. Samples were wrap or vacuum packaged and irradiated with 0, 3, 4.5, 6 and 7.5 kGy using electron-beam accelerator at Samsung Heavy Industries Ltd. Co. (in Taejun). Irradiated samples were cooked with different methods(electronic pan and gas oven) and temperatures ($ 60^{\circ}C, 70^{\circ}C and 80^{\circ}C$) and used to measure fatty acid composition, TBARS, cholesterol oxide products and panel test scores. The content of saturated fatty acids increased by increasing heating temperature in oven boiling steak (OBS) and pan boiling steak (PBS), and there was no difference by electron-beam irradiation. Both irradiated and non-irradiated treatment were high as the heating temperature increased in TBARS by heating temperature in PBS (p < 0.05) and the amount of Malonaldehyde (MA), standard of fat deterioration, was increased in OBS (p < 0.05). Non-irradiated and 3, 6 kGy treatment produced about 2 fold amount of MA at $ 60^{\circ}C $ compared with $ 80^{\circ}C $. In comparison with PBS, OBS produced much amount of MA and a bit different from non-irradiated treatment but did not show no tendency. As irradiation levels and heating temperature increased, the amount of cholesterol oxides products was increased and also pan-heating method, direct heating method, significantly increased the degree of oxidation compared with oven-heating method, indirect heating method (p < 0.05).