• Journal of Animal Science and Technology
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• v.53 no.5
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• pp.475-480
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• 2011

This study was conducted to investigate the effects of different feeding level of TDN (Total Digestible Nutrients) on the generation of main greenhouse gases such as carbon dioxide and methane in Hanwoo cows. The diet TDN (kg) adjusted to achieve ADG of 0 g/day (Control), 200 g/day (T1), and 400 g/day (T2) of the maintenance level TMR (Total Mixed Ration) delivered twice a day at 08:30 and 17:30. Cow are housed in a respiration chamber and the environmental temperature was maintained at $20^{\circ}C$. The gases were measured for 24 hours using the multi-detector instrument Mamos-300. The analyzed methane emissions of T1 and T2 were 33.5% and 69.6% higher than control, respectively, and the carbon dioxide emissions were 21.1% and 40.6% higher than control. Also, the hourly pattern of carbon dioxide and methane production were showed very similar emission. Gas production showed peak after 1 hour of feeding and this gap was wider in the afternoon than in the morning hours. It is clearly conducted that $CO_2$ and $CH_4$ emissions were different by limited intake levels of feed.

• Journal of Animal Science and Technology
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• v.51 no.2
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• pp.97-104
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• 2009

Complement of test standard, evaluation methods and models are needed to improve national competitiveness and to exchange superior genetic resources through the comparison of genetic evaluation score among nations in dairy cattle. Therefore, this study was conducted for the application of international standard to Korea considering domestic circumstance by changing linear-classification test score system of 50 classes which is currently used in Korea to system of 9 classes which is used in advanced nations of dairy. 15,230 of holstein cow linear type records with first parity records for the fifteen linear type and one total score from 2001 to 2006 and pedigree data which were collected by the Korean Animal Improvement Association were used in this study. Population classified by 9 levels was more normal distributed than 50 levels. Correlation coefficients between 50 and 9 score system showed over 0.98 by each classification scheme. Therefore, the 50 point system can be substituted with 9 point system due to their highly positive correlation. However, scores in all traits were still very contingent on classifier under the 9 point system (p<0.001), and F values between foot angle and front teat attachment showed high fluctuation depending on classifier. It means that subjective opinions of classifier would influence on linear type score as ever even if class scheme transformed to system of 9 class. Therefore, the relevance of transformation to the 9 point system should be assessed after analyses about various environmental factors.

• Journal of Animal Science and Technology
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• v.62 no.2
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• pp.263-275
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• 2020

Studies on promoting milk protein yield by supplementation of amino acids have been globally conducted. Nevertheless, there is a lack of knowledge of what pathways affected by individual amino acid in mammary epithelial cells that produce milk in practice. Phenylalanine (PHE) and valine (VAL) are essential amino acids for dairy cows, however, researches on mammary cell levels are still lacking. Thus, the aim of this study was conducted to evaluate the effects of PHE and VAL on milk protein synthesis-related and energy-mediated cellular signaling in vitro using immortalized bovine mammary epithelial (MAC-T) cells. To investigate the effects of PHE and VAL, the following concentrations were added to treatment medium: 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mM. The addition of PHE or VAL did not adversely affect cell viability compared to control group. The concentrations of cultured medium reached its maximum at 0.9 mM PHE and 0.6 mM VAL (p < 0.05). Therefore, aforementioned 2 treatments were analyzed for proteomics. Glucose transporter 1 and mammalian target of rapamycin mRNA expression levels were up-regulated by PHE (166% and 138%, respectively) (p < 0.05). Meanwhile, sodium-dependent neutral amino acids transporter type 2 (ASCT2) and β-casein were up-regulated by VAL (173% in ASCT2, 238% in and 218% in β-casein) (p < 0.05). A total of 134, 142, and 133 proteins were detected in control group, PHE treated group, and VAL treated group, respectively. Among significantly fold-changed proteins, proteins involved in translation initiation or energy metabolism were detected, however, expressed differentially between PHE and VAL. Thus, pathway analysis showed different stimulatory effects on energy metabolism and transcriptional pathways. Collectively, these results showed different stimulatory effects of PHE and VAL on protein synthesis-related and energy-mediated cellular signaling in MAC-T cells.

• 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.

• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.225-230
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• 2000

This study was designed to investigate effect of cryoprotectant kinds and cell stages on the viability of bovine embryos cryopreserved by vitrification. The oocytes were collected from ovarian follicles of Korean native cows. The follicular oocytes were cultured in TCM-199 medium containing hormone and 10%(v/v) FCS for 24~48hrs in a incubator with 5% $CO_2$, in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 7~10 hrs with spermatozoa capacitated by preincubation. The vitrification solutions of EFS and EDS were consisted of 40%(v/v) ethylene glycol, 18%(v/v) Ficoll and 0.3M sucrose, and 20%(v/v) ethylene glycol, 16.5%(v/v) DMSO and 0.5M sucrose in TCM-199 medium supplemented with 10% FCS, respectively. The embryos were exposed to EFS or EDS at $25^{\circ}C$ and loaded into OPP straw for 30 sec. The plug end of each straws was heat-sealed and straws was slowly immersed into liquid nitrogen(L$N_2$). The results obtained were summarized as follows : 1 . The rates of cleavage and hatching of embryos frozen with vitrification, rapid and slow freezing methods were 67.5%, 27.5% and 42.5%, 20.0% and 52.5%, 25.0%, respectively And rates of cleavage and hatching of embryos frozen with vitrification method were significantly(p<0.05) higher than those in other methods, and the rates were lower than those in control group(82.5% and 37.5%). 2. The rates of cleavage and hatching of embryos were significantly(p<0.05) different between EFS(47.5% and 22.5%) and EPS(52.5% and 27.5%), and the rates were lower than those in control group(82.5% and 37.5%). 3. After vitrification freezing of bovine embryos at zygote, 2 cell, 8 cell, morulae and blastocyst stage, the rate of cleavage and hatching were 25.0% and 15.0%, 32.5% and 20.0%, 37.5% and 20.0%, 52.5%, 27.5%, 47.5% and 25.0%, respectively. And developmental rates to the expended blastocyst stage of embryos frozen at zygote stage was significantly(p<0.05) lower rather than those in 2, 8-cell and morulae stage.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.629-636
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• 2008

This study was carried out to compare the quality of beef from outdoor-reared before finishing and indoor-reared Hanwoo. Among the experimental animals, $28{\pm}4$ mon-aged Hanwoo cows (n=5) were outdoor-reared for 7 mon (April-November) and then indoor-reared for 6 mono The 6 mon-aged Hanwoo steers (n=10) were indoor-reared for 24 mono The M. longissimus from all animals were stored at $4{\pm}0.2^{\circ}C$ for 7 days. Carcasses from outdoor-reared cattle before finishing were lighter, firmer, maturer, and leaner than indoor-reared (p<0.05). The beef from outdoor-reared cattle had lower crude fat and n-6 PUFA contents, n-6/n-3 ratio, and higher n-3 PUFA and SFA contents than indoor-reared (p<0.05). The pH and water-holding capacity were lower in beef from outdoor-reared cattle than in indoor-reared (p<0.05). The aroma pattern by electronic nose was discriminately different between beef from outdoor-reared and indoor-reared cattle. During storage, beef from outdoor-reared cattle showed lower lipid and myoglobin oxidation stabilities, and a darker and less red color than indoor-reared.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.8
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• pp.1242-1251
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• 2020

Objective: The 3×3 factorial arrangement was used to investigate if either high water-soluble carbohydrates (WSC) cultivars or suitable time of day that the grass cut could improve nutrient values and in vitro fermentation characteristics. Methods: The 3 cultivars were mowed at 3 diurnal time points and included a benchmark WSC ryegrass cultivar 'Premium', and 2 high WSC cultivars AberAvon and AberMagic, which contained, on average, 157, 173, and 193 g/kg dry matter (DM) of WSC, and 36.0, 36.5, and 34.1 g/kg DM of N during 7th regrowth stage, respectively. The fermentation jars were run at 39℃ with gas production recorded and sampled at 2, 5, 8, 11, 14, 17, 22, 28, 36, and 48 h. The rumen liquid was collected from 3 rumen fistulated cows grazing on ryegrass pasture. Results: High WSC cultivars had significantly greater WSC content, in vitro DM digestibility (IVDMD) and total gas production (TGP), and lower lag time than Premium cultivar. Methane production for AberMagic cultivar containing lower N concentration was marginally lower than that for AberAvon and Premium cultivars. Grass cut at Noon or PM contained greater WSC concentration, IVDMD and TGP, and lower N and neutral detergent fiber (NDF) contents, but CH₄ production was also increased, compared to grass cut in AM. Meanwhile, the effects of diurnal cutting time were influenced by cultivars, such as in vitro CH₄ production for AberMagic was not affected by cutting time. The IVDMD and gas production per unit of DM incubated were positively related to WSC concentration, WSC/N and WSC/NDF, respectively, and negatively related to N and NDF concentrations. Conclusion: These results imply either grass cut in Noon or PM or high WSC cultivars could improve nutrient values, IVDMD and in vitro TGP, and that AberMagic cultivar has a slightly lower CH₄ production compared to AberAvon and Premium. Further study is necessary to determine whether the increase of CH₄ production response incurred by shifting from AM cutting to Noon and/or PM cutting could be compensated for by high daily gain from increased WSC concentration and DM digestibility.

• Journal of Veterinary Clinics
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• v.20 no.1
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• pp.66-73
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• 2003

Numerous physiological effects are attributed to conjugated linoleic acid(CLA). The purpose of this study is to consider these effects with respect to the cis-9, trans-11 and trans-10, cis-12 CLA isomer. Both isomers are natural products. The c9,t11-CLA isomer is the principal dietary form of CLA, but the concentrations of this isomer and the t10,c12-CLA Isomer in dairy products or beef vary depending on the diet fed to cows or steers, respectively. The influence of dietary CLA isomers on the immune response was examined, body weight and weight ratio of organ to body of Balb/C mice. Mice were divided into four groups of 8 mice. Balb/C mice were fed the experimental diets supplemented with 1% CLA (c9,t11-CLA isomer : t10,c12-CLA isomer = 2:3) (Group 1), 1% CLA (c9,t11-CLA isomer t10,c12-CLA isomer : 1:1) (Group 2), 1% safflower oil (Group 3) or nothing (Control) for 3 weeks. After 3 weeks, serum, gut lumen lavage, fat, liver, spleen and thymus were taken. Measurement of total immunoglobulin were executed using sandwich ELISA. Serum levels of IgA and IgM showed that group fed with t10,c12-CLA isomer significantly were higher than group fed with c9,tl1-CLA isomer. In addition serum level of IgG showed that group fed with t10,c9-CLA isomer significantly were lower than group fed with c9,tl1-CLA isomer. However, no significantly differences were observed in the serum IgE and secretory IgA. Weight ratio of spleen to body showed no significant differences. In weight ratio of liver and thymus to body, tl0,c9-CLA isomer significantly were respectively higher than group fed with c9,t11-CLA isomer. In weight ratio of fat to body, tl0,c9-CLA isomer significantly were respectively lower than group fed with c9,tl1-CLA isomer. In conclusion, t10,c12-CLA isomer produced a situation favorable for immunopotentiative effect and body composition. But it should be protected against hepatomegaly induced lipid accumulation in liver.

• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.143-151
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• 1992

Sixty Four fresh and 142 frozen embryos of dairy cattle were transferred to synchronized dairy, beef or Korean Native Cattle nonsurgically at National Animal Breeding Institute from 1985 to 1990. The results obtained were as follows ; 1. The pregnancy rate of fresh embryos(39.1%) was higher than that of frozen embryos(32.4%) and average pregnancy rate was 34.5%. 2. The pregnancy rate of grade 1 embryos was higher than that of grade 2 embryos for both fresh(41.3% vs 33.3%) and frozen embryos(35.4% vs 25.6%). 3. The pregnancy rate according to development stage of fresh embryos was increased with maturity as 29.2%, 33.3%, 50.0% and 54.5% for morula, early blastocyst, blastocyst and expanded blastocyst, respectively. For frozen embryos, the pregnancy rate of blastocyst(44.4%) was higher than those of morula(31.3%) and early blastocyst(28.0%). 4. The pregnancy rate according go recipient-donor synchrony for fresh embryos was higher when the recipients exhibited estrus 1 day earlier than the donors(43.8%) than when the recipients exhibited estrus 1 day later than the donors(38.1%) or when the recipients and donors exhibited estrus at the same time(37.0%). For forzen embryos, the pregnancy rate was decreased when the recipients and donors exhibited estrus at the same time(37.9%), when the recipients exhibited estrus 1 day later than the donors(32.0%) and when the recipients exhibited estrus 1 day earlier than the donors(23.5%), in sequence. 5. The pregnancy rate of heifers was higher than that of cows for both fresh(50.5% vs 37.9%) and frozen embryos(39.7% vs 25.7%). 6. The pregnancy rate according to recipient breed for fresh embryos was higher in dairy cattle(42.1%) and beef cattle(40.%) than in Korean Native Cattle(33.3%). For frozen embryos, the pregnancy rate was decreased beef cattle(39.1%), dairy cattle(30.3%) and Korean Native Cattle(14.3%), in sequence. 7. The pregnancy rate according to equilibrium steps of glycerol and freezing rate was higher when transferred after 3-steps equilibrium and freezing by the rate of $0.3^{\circ}C$/min from $-6^{\circ}C$ to $-35^{\circ}C$ and $0.1^{\circ}C$/min to $-38^{\circ}C$(39.4%) than when transferred after 6-steps equilibrium and freezing by the rate of $0.5^{\circ}C/min$ from $-6^{\circ}C$ to $-30^{\circ}C$(30.3%).

• Journal of Dairy Science and Biotechnology
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• v.34 no.1
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• pp.37-41
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• 2016

Melatonin is a hormone produced by the pineal gland in dark conditions. It plays a major role in the regulation of the sleep-wake cycle. Melatonin synthesis is known to be suppressed by environmental light. Cortisol is a steroid hormone that is a major indicator of physiological alterations due to stressful stimuli. It also displays a circadian rhythm, like melatonin. The highest levels are encountered during early morning and the lowest levels are observed at around midnight. In the present study, the effects of milking time on the melatonin and cortisol concentrations of raw milk and milk powder at the summer and winter solstices were examined. The melatonin concentration in milk increased significantly if cows were milked in the dark at night (p<0.05). The melatonin concentration in milk powder showed the same pattern with respect to the milking time (p<0.05). However, no significant difference in the cortisol concentration was observed between day- and night-time milk. Although the time of day did not affect the level of milk cortisol, seasonal factors affected the release of cortisol in milk (p<0.05). In conclusion, night-time milk is rich in endogenous melatonin. In this respect, it has potential applications for the development of melatonin rich-dairy products, which serve as natural sources of melatonin.