• Proceedings of the Korean Society of Developmental Biology Conference
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• 2001.10a
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• pp.37-43
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• 2001

1. About fifty thousand of cattle embryos were transferred and 16000 ET-calves were born in 1999. Eighty percents of embryos were collected from Japanese Black beef donors and transferred to dairy Holstein heifers and cows. Since 1985, we have achieved in bovine in vitro fertilization using immature oocytes collected from ovaries of slaughterhouse. Now over 8000 embryos fertilized by Japanese Black bull, as Kitaguni 7~8 or Mitsufuku, famousbulls as high marbling score of progeny tests were sold to dairy farmers and transferred to their dairy cattle every year. 2. Embryo splitting for identical twins is demonstrated an useful tool to supply a bull for semen collection and a steer for beef performance test. According to the data of Dr. Hashiyada(2001), 296 pairs of split-half embryos were transferred to recipients and 98 gave births of 112 calves (23 pairs of identical twins and 66 singletons). 3. A blastomere-nuclear-transferred cloned calf was born in 1990 by a joint research with Drs. Tsunoda, National Institute of Animal Industry (NIAI) and Ushijima, Chiba Prefectural Farm Animal Center. The fruits of this technology were applied to the production of a calf from a cell of long-term-cultured inner cell mass (1988, Itoh et al, ZEN-NOH Central Research Institute for Feed and Livestock) and a cloned calf from three-successive-cloning (1997, Tsunoda et al.). According to the survey of MAFF of Japan, over 500 calves were born until this year and a glaf of them were already brought to the market for beef. 4. After the report of "Dolly", in February 1997, the first somatic cell clone female calves were born in July 1998 as the fruits of the joint research organized by Dr. Tsunoda in Kinki University (Kato et al, 2000). The male calves were born in August and September 1998 by the collaboration with NIAI and Kagoshima Prefecture. Then 244 calves, four pigs and a kid of goat were now born in 36 institutes of Japan. 5. Somatic cell cloning in farm animal production will bring us as effective reproductive method of elite-dairy- cows, super-cows and excellent bulls. The effect of making copy farm animal is also related to the reservation of genetic resources and re-creation of a male bull from a castrated steer of excellent marbling beef. Cloning of genetically modified animals is most promising to making pig organs transplant to people and providing protein drugs in milk of pig, goat and cattle. 6. Farm animal cloning is one of the most dreamful technologies of 21th century. It is necessary to develop this technology more efficient and stable as realistic technology of the farm animal production. We are making researches related to the best condition of donor cells for high productivity of cloning, genetic analysis of cloned animals, growth and performance abilities of clone cattle and pathological and genetical analysis of high rates of abortion and stillbirth of clone calves (about 30% of periparutum mortality). 7. It is requested in the report of Ministry of Health, labor and Welfare to make clear that carbon-copy cattle(somatic cell clone cattle) are safe and heathy for a commercial market since the somatic cell cloning is a completely new technology. Fattened beef steers (well-proved normal growth) and milking cows(shown a good fertility) are now provided for the assessment of food safety.

• Proceedings of the Korean Society of Grassland Science Conference
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• 2002.09b
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• pp.131-156
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• 2002

Although economically viable, the livestock industry is currently facing a number of challenging environmental problems and highly complex social issues, many of which are related to its size and geographically concentrated nature. Increased emphasis on environmental quality has also placed new demands on livestock producers to ensure that their production practices are in harmony with natural environment. In terms of sustainable agricultural systems, ruminants have served and will continue to serve a valuable role. They are particularly useful in converting vast renewable resources from rangeland, pasture, and crop residues or other by-product into food edible for human. With ruminants, land that is too poor or too erodable to cultivate becomes productive. Also, nutrients in by-products are utilized and do not become a waste-disposal problem. In Korea, however, native and dairy cattle production is not consistent with the advantageous roles of ruminant livestock in sustainable agricultural system because imported feed grains become the main basis for cattle raising. At present the ruminant livestock producers are heavily concentrated in and around the urban areas. About 75% of all the nation's cattle herds are kept on the outskirts of urban areas. As a result, the amount of pasture and forage land available per head of cattle is generally small. Furthermore, animals are raised in a cattle shed with high density. This situation is rather unfavorable for the national economic and environmental points of view As nation income increased, the demand for livestock products grew at an unforeseeable pace. But the pasture area involving in current utilization is tended to decrease during recent years. Based on the above figures more than 250,000 ha of pasture ought to be available for the present herd of cattle. It is obvious that these needs can scarcely be met with arable lands. Lands area for the establishment of new grassland have to be found in the hills and mountains which have not yet been used for crop framing or livestock. The development of extensive grasslands in the hill and woodland areas is now a declared aim. The starting point of the present work is the lack of knowledge of forage production and utilization in hill pasture and woodland in spite of indispensable necessity for livestock production in Korea. The importance of pastoral system in hill region and woodland is particularly emphasized in a standpoint of sustainable livestock production. Main chapter comprises the principle and techniques applicable for improving the utilization of hill pasture and woodland. We finally discussed the problems to solve and future works for a successful livestock production in hill and mountainous area in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1689-1695
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• 2008

Leptin, the hormone product of the obese gene, is secreted predominately from white adipose tissue and regulates feed intake, energy metabolism and body composition. It has been considered a candidate gene for performance, carcass and meat quality traits in beef cattle. The objective of this study was to identify SNPs in the promoter region of the leptin gene and to evaluate the possible association of the SNP genotypes with carcass and meat quality traits in Korean cattle. We identified a total of 25 SNPs in the promoter region (1,208-3,049 bp upstream from the transcription start site) of the leptin gene, eleven (g.1508C>G, g.1540G>A, g.1545G>A, g.1551C>T, g.1746T>G, g.1798ins(G), g.1932del(T), g.1933del(T), g.1934del(T), g.1993C>T and g.2033C>T) of which have not been reported previously. Their sequences were deposited in GenBank database with accession number DQ202319. Genotyping of the SNPs located at positions g.2418C>G and g.2423G>A within the promoter region was performed by direct sequencing and PCR-SSCP method to investigate the effects of SNP genotypes on carcass and meat quality traits in Korean cattle. The SNP and SSCP genotypes from the two mutations of the leptin promoter were shown to be associated with the BF trait. The average BF value of animals with heterozygous SNP genotype was significantly greater than that of animals with the homozygous SNP genotypes for the g.2418C>G and g.2423G>A SNPs (p<0.05). Analysis of the combined genotype effect in both SNPs showed that animals with the AC SSCP genotype had higher BF value than animals with BB or AA SSCP genotypes (p<0.05). These results suggest that SNP of the leptin promoter region may be useful markers for selection of economic traits in Korean cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.6
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• pp.826-833
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• 2019

Objective: This study was performed to evaluate whether hot temperature and rumen-protected fat (RPF) supplementation affect growth performance, rumen characteristics, and serum metabolites in growing stage of Korean cattle steers. Methods: Twenty Korean cattle steers ($230.4{\pm}4.09kg$ of body weight [BW], $10.7{\pm}0.09months$ of age) were divided into a conventional control diet group (n = 10) and a 0.8% RPF supplementation group (n = 10). Steers were fed 1.5% BW of a concentrate diet and 4 kg of tall fescue hay for 16 weeks (July 10 to August 6 [P1], August 7 to September 3 [P2], September 4 to October 1 [P3], October 2 to 30 [P4], of 2015). Results: The mean temperature-humidity index (THI) was higher (p<0.001) in P1 (76.8), P2 (76.3), and P3 (75.9) than in P4 (50.9). The mean THI of P1-3 were within the alert heat stress (HS) category range according to previously reported categories for feedlot cattle, and the mean THI of P4 was under the thermo-neutral range. Neither month nor RPF supplementation affected (p>0.05) average daily gain and gain to feed ratio. Month and RPF supplementation affected concentrations of glucose, albumin, and high-density lipoprotein (HDL); those of albumin and glucose tended to decrease (p<0.10), but HDL concentration increased (p<0.01) by RPF supplementation. Neither month nor RPF affected (p>0.05) ruminal pH, $NH_3-N$, and volatile fatty acid concentrations, whereas the C2:C3 ratio was affected (p<0.05) by month. Conclusion: Korean cattle may not have been significantly affected by alert HS during the growing stage. Growth performance was higher during hotter months, although some changes in blood metabolites were observed. The RPF supplementation affected some blood lipids and carbohydrate metabolites but did not affect growth performance.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.869-879
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• 2016

The present study was conducted to evaluate the effects of dietary formulated feed additive on growth performance and carcass traits of Hanwoo steers. A formulated feed additive reported to reduce heat load in the rumen in our previous research was used (Cho et al., 2014). Total 32 herds of Hanwoo steers were assigned into two groups of control and treatment. Total mixed ration was provided as basal diet for cattle and 100 g of additive was supplemented on diet for treatment. Feeding trial was performed during 120 days before slaughter. For growth performance, 3 periods (0~90 days; 90~120 days; 0~120 days) were allotted and average daily gain, feed requirement and final body weight were determined. Loin meat between $12^{th}$ and $13^{th}$ rib was used for meat quality analysis after slaughtering. Only $1^{st}$ period showed significantly improved growth performance of treatment (P<0.05) and there were no significant difference in other periods. At $3^{rd}$ periods (overall), a trend of increased average daily gain was found at treatment (P=0.075). Carcass performance and quality did not show significant differences between treatment and control (P>0.05). In meat quality, treatment showed significant increment in all measured meat colors (P<0.05) and significantly less sharing force compared to the control (P<0.05). Although no significant difference in growth performance and carcass yield were found, remarkably improved economic status was detected in treatment group. In conclusion, it could be suggested that application of a formulated feed additive specialized in reduction of heat load in the rumen was able to increase economical balance through enhancing heat stress condition of ruminant and growth.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.1
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• pp.1-6
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• 1989

Nutritive values and fermentation rates of rice straw treated with 3% anhydrous and 3% aqueous ammonia were evaluated both in vitro and sheep metabolism trials. Daily gain, feed efficiency and feed cost per gain were also determined with growing Holstein bulls fed anhydrous and aqueous ammonia treated rice straw. Crude protein was increased 2.4 fold and NDF was decreased 6.5%, but ADF and cellulose were not different between untreated and ammonia treated rice straw. An average of 35.5% of total added ammonia-N retained in the rice straw and other 64.5% was not retained in the rice straw. Ammonia treatment increased in vitro DM, NDF, ADF and cellulose digestibilities by 44.8%, 43.3%, 49.4% and 42.4%, respectively, and fermentation rates by 63.3%, 132.4%, 49.4% and 42.4%, respectively. In sheep metabolism trials, DM digestibilities of rice straw treated with anhydrous and aqueous ammonia were increased 22% and 36%, respectively, and digestible DM intakes by 48% and 70%, respectively in sheep fed anhydrous and aqueous ammonia treated rice straw over untreated rice straw. Rumen ammonia and blood urea were considerably higher in sheep fed ammonia treated rice straw than sheep fed untreated rice straw. Daily gain of Holstein bulls was increased 20.8% and 29.9% and rice straw intakes were increased 28.4% and 44.3% in anhydrous and aqueous ammonia treated rice straw over untreated rice straw. Feed conversion was improved 9.5% and 10.3% and feed cost/gain was reduced 7.1% and 9.2% respectively in anhydrous and aqueous ammonia treated rice straw group as compared with untreated rice straw group.

• Korean Journal of Veterinary Service
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• v.39 no.3
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• pp.167-174
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• 2016

In this study, we analyzed for the changes of low organic compounds during 4 weeks incubation though inoculation of harmful microorganisms on commercial feed. Two percent of overnight cultures of Exiguobacterium acetylicum, Acinetobacter calcoaceticus, Aspergillus flavus and Fusarium graminearum were inoculated in feed, respectively. After adjusting moisture level to 50% for the promotion of feed spoilage, pH was decreased to 4.58~5.03 and microorganism was ranged to $6{\sim}10log_{10}CFU/g$. The compounds were compare between aflatoxin G1 producing feeds and aflatoxin G1 non-producing feeds. Aflatoxins G1 were detected by the immunoaffinity column clean-up method with HPLC-FLD, and were confirmed in samples incoulated by Aspergillus flavus and Acinetobacter calcoaceticus. Koiganal II, cyclohexanol and butadien-one were detected from samples (the non-sterilized inoculated feed) by Aspergillus flavus and Acinetobacter calcoaceticus. Respectively as aflatoxin G1 pre-detected substance, Koiganal II, cyclohexanol and butadien-one may be useful substance for the pre-detection of aflatoxin G1.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.831-842
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• 2021

Accurate measurements of feed energy values have a positive effect on the control of feed intake for animals, the formation of prices, and on economic profits. However, few studies have attempted to measure the energy values of domestic roughages and to validate an energy value prediction model. The purpose of this study is to build a database through measurements of the nutrient digestibility and digestible energy results of roughages used in Korea and to evaluate the domestic applicability of the National Research Council (NRC) estimation model. Oat hay, annual ryegrass, tall fescue, barnyard millet, and concentrates for beef cattle were used in the test. As a result of an in vivo digestibility trial, the total digestible nutrients (TDN) of oat hay, annual ryegrass, tall fescue, and barnyard millet were found to be 68.73, 55.02, 55.71, and 52.89%, respectively. As a result of comparing the estimated values using the NRC equation with the in vivo results, there was a difference of 3.55 to 6.84%P in the TDN. Inferred from this result, it is considered that TDN calculations using the NRC equation can be reasonable for the test feeds used in this study. These results can be utilized when revising the Korean Standard Tables of Feed Composition, which provides a comprehensive overview of Korean feed.

• Journal of Food and Nutrition Research
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• v.9 no.7
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• pp.363-366
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• 2021

This study aimed to determine the effect of regulating crude protein (CP) levels in total mixed ration (TMR) on the growth performance and carcass characteristics of Hanwoo steers. The regimens were divided into a control group (TMR with 15% CP) and treatment group (TMR with 12.5% CP). The viable cell count and fermentation potential of the prepared experimental feed and the nutrient digestibility were evaluated. Growth performance and carcass characteristics were confirmed by evaluating the weight and intake of Hanwoo steers, and an economic analysis was performed. Only CP digestibility was higher in the control group than in the treatment group (p<0.05). There were no significant differences in the initial and final body weights, daily gain, and feed requirements between the groups (p>0.05). There were no significant differences in carcass weight, yield index, back fat thickness, and loin area (p>0.05), but the appearance rate of quality grade A was higher in the treatment group than in the control group. In addition, there was no difference in the meat quality characteristics, such as marbling, meat color, fat color, texture, and maturity (p>0.05), and the treatment group had a higher rate of 1++ grade than the control group. Economic analysis showed that when 10 cattle were shipped, the control group received a price of 100,041 thousand won, and the treatment group received a price of 102,033 thousand won. When the income for each group was calculated, the production cost of the treatment group was 8% lower than that of the control group; thus, a higher net profit could be expected considering the low feed cost. Therefore, the economic feasibility of steer raising could be improved while maintaining productivity by controlling CP levels in feed. In addition, this study provides useful basic data for precisely adjusting the CP levels in feed for Hanwoo steers.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.4
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• pp.505-513
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• 2017

Objective: This study was performed to evaluate whether ambient temperature and dietary glycerol addition affect growth performance, and blood metabolic and immunological parameters, in beef cattle. Methods: Twenty Korean cattle steers ($405.1{\pm}7.11kg$ of body weight [BW], $14.2{\pm}0.15$ months of age) were divided into a conventional control diet group (n = 10) and a 2% glycerol- added group (n = 10). Steers were fed 1.6% BW of a concentrate diet and 0.75% BW of a timothy hay diet for 8 weeks (4 weeks from July 28th to August 26th and 4 weeks from August 27th to September 26th). Blood was collected four times on July 28th, August 11th, August 27th, and September 26th. Results: The maximum indoor ambient temperature-humidity index in August (75.8) was higher (p<0.001) than that in September (70.0), and in August was within the mild heat stress (HS) category range previously reported for dairy cattle. The average daily gain (ADG; p = 0.03) and feed efficiency (p<0.001) were higher in hotter August than in September. Glycerol addition did not affect ADG and feed efficiency. Neither month nor glycerol addition affected blood concentrations of cortisol, triglyceride, or non-esterified fatty acid. Blood concentrations of cholesterol, low-density lipoprotein, high-density lipoprotein, glucose, and albumin were lower (p<0.05) on August 27th than on September 26 th, and blood phosphorus, calcium and magnesium concentrations were also lower on August 27th than on September 27th. Glycerol addition did not affect these blood parameters. Percentages of $CD4^+$ T cells and $CD8^+$ T cells were higher (p<0.05) on July 28th than on August 27th and September 26th. The blood $CD8^+$ T cell population was lower in the glycerol supplemented-group compared to the control group on July 28th and August 27th. Conclusion: Korean cattle may not be significantly affected by mild HS, considering that growth performance of cattle was better in hotter conditions, although some changes in blood metabolic and mineral parameters were observed.