• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.281-288
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• 2000

This experiment was carried out to investigate the optimal activation condition for parthenogenetic development. In order to activate oocytes at 22 h post onset of maturation, the oocytes were subjected to 5 $\mu$M ionomycin(I) for 5 min ,10 $\mu$M calcium ionophore(Ca) for 5 min, 2 mM 6-dimethylamino-purine(DMAP) for 3 h and 10 $\mu\textrm{g}$/$m\ell$ cycloheximide(CH) for 6 h alone or in combination. The activated oocytes were cultured in modified CR$_1$aa at 5% $CO_2$, 5% $O_2$, 90% $N_2$. l. The cleavage rates after 48 h culture of oocytes treated with I, Ca, DMAP and CH were 12.7%, 14.1%, 28.9% and 22.9%, respectively. There was no blastocyst formation. 2. The cleavage rates after 48 h culture of oocytes treated with I ＋ DMAP, I ＋ CH, Ca ＋ DMAP and Ca ＋ CH were 96.9%, 82.1%, 93.1% and 34.7%, respectively. Developmental rates to blastocysts were 10.4%, 5.3%, 17.6% and 7.1 %, respectively. When oocytes were treated with Ior Ca followed by DMAP, the blastocyst formation rate was significantly higher than other groups(P <0.05). 3. According to single activation treatment, pronucleus formation rates were 5.4%, 3.6%, 28.3% and 28.8%, respectively, Whereas, all oocytes treated with the combined activation agents formed 100% pronucleus.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.195-199
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• 2011

The objective of this study was to evaluate the efficiency of the conventional slow freezing and vitrification methods for cryopreserving in vivo and in vitro-produced bovine embryos. Morphology of post-thawed embryos was evaluated and normal embryos were used for successive culture for 72 h. In experiment I, In embryo viability, There was no significant differences in blastocyst re-expansion rates were found between in vivo and in vitro embryos(89.6% vs. 81.5%). whereas hatched-BL and total cell number rates was significantly higher (p<0.05) for in vivo-derived embryos (76.9%, 136${\pm}$3.6 vs. 43.4%, 107${\pm}$3.8). In experiment II, There was no significant differences in blastocyst re-expansion and Expansion-BL rates were found between in slow freezing and vitrification methods (91.3% vs. 85.7% and 71.4% vs. 75.0%, respectively). in conclusion, These results suggested that the field application for bovine embryo transfer is in part supported by improvements of technologies in embryo conventional slow freezing and vitrification cryopreservation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.104-108
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• 2016

The objective of this study was to determine how feeding forage and concentrate separately (SF) or as a total mixed ration (TMR) affects enteric methane production of cattle. Six Holstein steers ($203{\pm}22.5kg$) were used in a $2{\times}3$ changeover design experiment. Experimental diets (TMR and SF) consisted of compound feed, timothy hay and soybean curd residue in a ratio of 40:48:12, respectively, and diets were fed at 10% of metabolic body weight, on an as-fed basis. There were no differences in dry matter intake and enteric methane production (g/d) between SF and TMR but the methane conversion rate (methane energy/GE intake) of TMR was significantly higher (p=0.05) than that of SF. The mean methane emission factor (kg/head/year) and conversion rate of the two treatments were 21.4 and 0.05, respectively. There was a strong relationship between metabolic body weight and enteric methane production (p<0.001). At the present time, further studies may be necessary in order to establish the effects of TMR and SF on enteric methane production.

• 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.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.509-516
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• 2003

Growth curves were estimated for 1083 female Korean cattle raised in Daekwanryeong branch, National Livestock Research Institute (NLRI). Comparisons were made among various growth curve models for goodness of fit for the growth of the cows. Estimated growth curve functions were $W_t=370.2e^{-2.208e^{-0.00327t}$ for Gompertz model, for von Bertalanffy model, and $W_t=341.2(1+5.652e^{-0.00524t})^{-1}$ for Logistic model. Ages at inflection estimated from Gompertz model, von Bertalanffy model and Logistic model were 242.2 days, 191.5 days, and 330.5 days respectively, body weight at inflection were 136kg, 115kg, and 170kg, and daily gain at inflection were 0.445kg, 0.451kg, and 0.446kg. The predicted weights by ages from Gompertz model, von Bertalanffy model, and Logistic model were onsistently overestimated at birth weight and underestimated at 36 month weight. The von Bertalanffy model which had a variable point of inflection fit the data best.

• Food Science of Animal Resources
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• v.22 no.3
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• pp.218-221
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• 2002

A total of 40 domestic-fed imported beef cattle were used to determine meat quality traits. Sirloin was taken from each 10 of Hereford, Angus, Hurray Grey(MG), Cross breed(Hereford$\times$Angus) and objective and subjective meat quality were assessed after a 7 days ageing(0$\pm$1$\^{C}$). Results showed that ultimate pH and fat hardness was not affected by breeds. MG showed a higher water holding capacity and consequently a lower cooking loss(%) than the other breeds(p<0.05). Angus sirloin was shown to be the toughest meat(assessed by WB-shear force), Hereford and MG resulted in the most tender meat(p<0.05). Objective meat color and sensory properties did not differ between the breeds. The current study indicated that the breeds had a similar characteristics in meat quality. However, further research on consumer preference including Hanwoo needs to be undertaken.

• Journal of Animal Science and Technology
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• v.58 no.9
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• pp.33.1-33.7
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• 2016

Background: The continuing growth of the ethanol industry has generated large amounts of various distillers grains co-products. These are characterized by a wide variation in chemical composition and ruminal degradability. Therefore, their precise formulation in the ruminant diet requires the systematic evaluation of their degradation profiles in the rumen. Methods: Three distillers grains plus soluble co-products (DDGS) namely, corn DDGS, high-protein corn DDGS (HP-DDGS), and wheat DDGS, were subjected to an in situ trial to determine the degradation kinetics of the dry matter (DM) and crude protein (CP). Soybean meal (SBM), a feed with highly degradable protein in the rumen, was included as the fourth feed. The four feeds were incubated in duplicate at each time point in the rumen of three ruminally cannulated Hanwoo cattle for 1, 2, 4, 6, 8, 12, 24, and 48 h. Results: Wheat DDGS had the highest filterable and soluble A fraction of its DM (37.2 %), but the lowest degradable B (49.5 %; P < 0.001) and an undegradable C fraction (13.3 %; P < 0.001). The filterable and soluble A fraction of CP was greatest with wheat DDGS, intermediate with corn DDGS, and lowest with HP-DDGS and SBM; however, the undegradable C fraction of CP was the greatest with HP-DDGS (41.2 %), intermediate with corn DDGS (2.7 %), and lowest with wheat DDGS and SMB (average 4.3 %). The degradation rate of degradable B fraction ($%\;h^{-1}$) was ranked from highest to lowest as follows for 1) DM: SBM (13.3), wheat DDGS (9.1), and corn DDGS and HP-DDGS (average 5.2); 2) CP: SBM (17.6), wheat DDGS (11.6), and corn DDGS and HP-DDGS (average 4.4). The in situ effective degradability of CP, assuming a passage rate of $0.06h^{-1}$, was the highest (P < 0.001) for SBM (73.9 %) and wheat DDGS (71.2 %), intermediate for corn DDGS (42.5 %), and the lowest for HP-DDGS (28.6 %), which suggests that corn DDGS and HP-DDGS are a good source of undegraded intake protein for ruminants. Conclusions: This study provided a comparative estimate of ruminal DM and CP degradation characteristics for three DDGS co-products and SBM, which might be useful for their inclusion in the diet according to the ruminally undegraded to degraded intake protein ratio.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.195-203
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• 2018

Interferon-tau (IFNT) is known as a major conceptus protein that signals the process of maternal recognition of pregnancy in ruminants. Also, multiple interferon genes exist in cattle, However, molecular mechanisms of these bovine IFNT (bIFNT) genes whose expressions are limited have not been characterized. We and others have observed that expression levels of bovine subtype IFNT genes in the tissues of ruminants; thus, bIFNT1 and other new type I (bIFNTc1/c2/c3) gene co-exist during the early stages of conceptus development and non-trophoblast cells. Its genes transcription could be regulated through CDX2 and ETS2 and JUN and/or cAMP-response element binding protein (CREB)-binding protein (CREBBP) expression, a transcription factor implicated in the control of cell differentiation in the trophectoderm. Bovine ear-derived fibroblast cells, were co-transfected with luciferase reporter constructs carrying upstream (positions -1000 to +51) regions of bIFNT1 and other new type I gene and various transcription factor expression plasmids. Compared to each - 1kb-bIFNT1/c1/c2/c3-Luc increased when this constructs were co-transfected with CDX2, ETS2, JUN and/or CREBBP. Also, Its genes was had very effect on activity by CDX2, either alone or with the other transcription factors, markedly increased luciferase activity. However, the degree of transcriptional activation of the bIFNTc1 gene was not similar to that bIFNT1/c2/c3 gene by expression plasmid. Furthermore, Sequence analyses also revealed that the expression levels of bIFNT1/c2/c3 gene mRNAs expression were highest on day 17, 20 and 22 trophoblast and, Madin-Darby bovine kidney (MDBK), Bovine ear-derived fibroblast (EF), and endometrium (Endo) non-trophoblast cells. But, bIFNTc1 mRNA had not same expression level, bIFNTc1 lowest levels than those of IFNT1/c2/c3 gene in both trophoblast and non-trophoblast cells. These results demonstrate that bovine subtype bIFNT genes display differential, in the trophoblast and non-trophoblast cells.

• Food Science of Animal Resources
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• v.30 no.6
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• pp.997-1006
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• 2010

The objective of this study was to investigate the proximate composition, pH, meat color, water holding capacity (WHC), cooking loss (CL), cholesterol content, and trans-fatty acid content of Hanwoo beef according to quality grade and cut. Five cuts [Cheggt (strip loin), Dngsim (loin), Moksim (chuck roll), Udoon (top round), Yanggi (brisket)] were obtained from 15 Hanwoo animals [3 bulls and 12 steers, 24-30 months old]. Three animals were selected from each quality grade of $1^{++}$, $1^+$, 1, 2, and 3. The protein and moisture contents (%) were significantly higher, and the fat contents (%) were significantly lower in 3 quality grade compared to the other grades (p<0.05). pH values of chuck roll and strip loin were significantly lower in $1^+$ quality grade (5.61 and 5.51) than those in 3 quality grade (5.88 and 5.92) (p<0.05). CIE L* values were significantly higher in the $1^{++}$ quality grade group (38.52-42.69%) than in 3 quality grade (33.02-36.08) (p<0.05). In the $1^{++}$ and 2 quality grade groups, CIE $L^*$ values of loin were significantly higher than those of other cuts (p<0.05). CIE $a^*$ values of loin (28.11) in 1 quality grade were the highest, whereas those of strip loin (15.36) in 3 quality grade were the lowest (p<0.05). WHC was not significantly different among the five cuts or quality grades. In CL, loin and strip loin were significantly lower in $1^{++}$ quality grade than in 3 quality grade (p<0.05), and they were also significantly lower (22.21-24.81%) than the other cuts in the same quality grade (p<0.05). The loin in $1^{++}$ (41.26 mg/100 g), $1^+$ (43.23), and 1 quality grades (48.63) had higher cholesterol contents (%) than in 2 (36.02) and 3 quality grades (29.84) (p<0.05). Cholesterol contents of the five cuts in $1^{++}$ quality grade (39.44-43.31%) were significantly higher than those in 3 quality grade (28.09-32.39%). The trans-fatty acid contents of the five cuts were 1.08-2.72%. The loin, strip loin, brisket, and top round in 3 quality grade had significantly higher trans-fatty acid contents than those of the other grades (p<0.05).