• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.238-246
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• 1994

This experiment was carried out to determine the effects of seeding date and fall harvest method on the growth characteristics, forage yield and quality of winter rye(Seca1e cereale L.) at the forage experimental field, College of Agriculture and Life Sciences, SNU, Suweon from 5 September 1992 to 21 May 1993. The experiment was arranged in a split plot design with three replications. Main plots consisted of three harvests, no defoliation, cutting and grazing. Sub-plots consisted of seeding dates, early(5 September), mid(25 September) and late(l0 October). The results obtained are summari7d as follows; I . A 3-day difference in the first heading of rye was observed between no defoliation and fall grazing, while there was a 6day difference between early and late seeding dates. Therefore, the effect of seeding dates on the fist heading date of rye was larger than that of fall harvest methods. 2. CP content of rye with fall grazing was slightly higher averaged 16.5% compared with both fall cutting and no defoliated 1ye(15.6%). Mean CP content of rye at the early, mid and late seeding dates was 14.2, 14.5 and 19.1 %, respectively. 3. ADF content of rye was slightly higher with both fall cutting(29.99) and no defoliation(29.5%) than that of fall grazing(28.0%). ADF content of rye at the early, mid and late seeding dates was 30.7, 29.1 and 27.7%, respectively. Effect of fall harvest methods and seeding dates on NDF content of rye were similar to the observations made on ADF. 4. RFV and IVDMD of rye were lower with both no defoliation and fall cutting than fall grazing. but those of rye slightly increased with seeding dates progressed. 5. Dry matter yield of rye was the highest of 6,779 kg/ha with fall cutting, while the lowest yield of 6,240 kg/ha was obtained from no defoliation But no significant difference was found among the harvest methods. Dry matter yield of rye was significantly declined with later seedings. It is concluded that the highest forage yield of rye be possible from two harvest systems of fall and spring with earlier seeding rather than from one harvest system of spring.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1710-1718
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• 2016

The objective of this study was to evaluate the effects of supplements with different crude protein (CP) contents on grazing cattle intake, digestibility, ruminal fermentation pattern, and nitrogen (N) metabolism characteristics during the rainy season. Five ruminal and abomasal cannulated Holstein${\times}$Zebu steers (296 kg body weight, BW) were used in a $5{\times}5$ Latin square design. The animals grazed five signal grass paddocks (0.34 ha). The five treatments evaluated were: Control (no supplement) and 1.0 g of supplement/kg BW with 0, 330, 660, and 1,000 g of CP/kg as-fed. The supplement was composed of starch, soybean meal, urea, and ammonium sulphate. There was a positive linear effect ($p{\leq}0.033$) of the CP content in the supplements on the organic matter (OM), CP, and digested OM intakes. The provision of supplements did not increase ($p{\geq}0.158$), on average, total and ruminal digestibilities of OM and CP. However, the increase in CP content in the supplements caused a positive linear effect ($p{\leq}0.018$) on ruminal digestibilities of OM and CP. Additionally, a quadratic effect of the CP contents of the supplements were observed (p = 0.041) for the ruminal digestibility of neutral detergent fiber corrected for ash and protein, with the highest estimate obtained with the CP content of 670 g/kg. The supply of supplements increased (p<0.001) the ruminal ammonia N concentration, which also changed linearly and positively (p<0.001) according to increase in CP content in the supplements. The apparent N balance and relative N balance (g/g N intake) were not, on average, changed ($p{\geq}0.164$) by the supplements supply. However, both showed a tendency of a linear increase ($p{\leq}0.099$) with increasing supplement CP content. The supplements increased (p = 0.007) microbial N production in the rumen, which also changed linearly and positively (p = 0.016) with increasing supplement CP content. In conclusion, protein supplementation in grazing cattle during the rainy season, while stimulating voluntary forage intake, results in higher efficiency of N utilization when compared to energy supplementation. This is a possible response to increased microbial protein synthesis in the rumen and improved N status in the animal body.

• Ocean and Polar Research
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• v.29 no.4
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• pp.401-410
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• 2007

In Korea the study of marine heterotrophic protists started in the late 1980s, and since the early 1990s many studies have been conducted in various marine environments. In this article, studies on the distribution and abundance of protists and the biotic interactions(bacteria-protists, phytoplankton-protists) conducted in Korean coastal waters are reviewed, and a field study is reported and discussed. The field study in Masan Bay was carried out from February 2004 to November 2005 at seven selected stations representative of the bay. During the study, the mean abundance of heterotrophic bacteria and the mean concentration of chlorophyll-a were $2.1{\times}10^6\;cells\;mL^{-1}$ and $9.8{\mu}g\;L^{-1}$, respectively. Heterotrophic protists consisted of heterotrophic dinoflagellates, heterotrophic nanoflagellates(excluding dinoflagellates) and ciliates, and their abundances were means of $7.9{\times}10^4\;cells\;L^{-1}$, $1.2[\times}10^3\;cells\;mL^{-1}$, and $4.0{\times}10^4\;cells\;L^{-1}$, respectively. Generally, the chlorophyll-a concentra+CZ14tions and the abundances of heterotrophic bacteria and protists were higher in the inner zone of the bay, where there are high concentrations of organic matters, than in the middle and outer zones. Using the grazing rates of heterotrophic nanoflagellates on bacteria previously reported in this area, it can be calculated that about 69% of bacterial producton was removed by HNF grazing activity. About 24% of initial chlorophyll-a concentration was removed by microzooplankton grazing activity. In conclusion, this study suggests that in Masan Bay heterotrophic protists control the growth of bacteria and phytoplankton, and heterotrophic protists represent an important link of bacterial & microalgal biomass to higher trophic levels.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.299-309
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• 2003

In an accidental release of radioactive materials to the environment the contaminative influence of animal products due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was investigated with the improvement of the Korean dynamic food chain model DYNACON Although mathematical models for both contaminative pathways have been established for considering all animal products and incorporated into the model, investigation was limited to milk. As a result, it was found that both pathways are influential in the contamination of milk in the case of an accidental release during the non-grazing period of dairy cows. In the case of an accidental release during the non-grazing period, the inhalation of air was more influential than the ingestion of soil in the early days following an accidental release. While, it was the opposite with the lapse of time. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was greater compared with the cases of no precipitation, in general, because of a stealer deposition of radionuclides onto the ground. Precipitation during an accidental release was a less influential factor in $^{131}I$ (elemental iodine) contamination compared with the $^{137}Cs\;and\;^{90}Sr$ contaminations. In the case of an accidental release during the grazing period of dairy cows, the contaminative influence due to the inhalation of air was negligible.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.5
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• pp.726-732
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• 2014

The objective of this study was to investigate the effect of maintenance system as well as the effect of Se, Zn, and vitamin E supplementation of ram-lambs on the slaughter value and concentration of mineral elements in the loin muscle of lambs. The experiment was conducted on 72 Polish Merino ram-lambs divided into three groups: group C, indoor with no supplement, 19 lambs; S, indoor with supplement, 23 lambs; G, outdoor with no supplement, 30 lambs. From birth all the lambs were maintained indoor with their dams and then weaned at the age of 8 weeks. The rams from group C and S were placed in individual straw-bedded pens and fattened individually with concentrate mixture offered ad libitum until the age of 16 weeks. The lambs from group G were grazed every day from May to July (2 months). During the fattening period each lamb from the supplemented group S was administered per os 1 mL 0.1% $Na_2SeO_4$ (Se, 0.42 mg), 3 mL 10% $ZnSO_4$ (Zn, 68 mg), and 1 mL premix protect vitamin E (0.1 g ${\alpha}$-tocopherol, 5 mg lysine, 5 mg methionine) daily. A comparison of half carcasses across the groups has shown no difference between the control group and the one with supplements, while the weight of half carcasses in the grazing group was smaller in comparison with groups C and S (p<0.001). The meat content in the pelvic limb showed no differences across all groups under study. The pelvic limb of grazing lambs contained less fat compared to the control and supplemented groups (p<0.001). The concentrations of Se and Zn in the blood plasma of ram-lambs from the supplemented group were significantly higher than for the control and grazing lambs. Inorganic Se and Zn supplementation with vitamin E to the diet of lambs increased Se and Zn levels in loin muscle (p<0.001) to $0.46{\mu}g/g$ and $32.9{\mu}g/g$ in fresh tissue, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.123-128
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• 2007

A study was conducted over two years to determine the temperate mixtures of grasses for grazing horses in Jeju, Korea. The experiment field located at 450 m altitude (Jeju Horse Training Center of Korea Racing Association) was divided into 3 different mixtures plots (3 replications) without a fence between treatments, and sown by three main grasses (orchardgrass, perennial ryegrass and timothy). Seven castrated adult horses were kept on pasture from the middle of April to the end of November without supplementary concentrates. The dry matter yield, percentage of grasses intake and botanical composition were determined during the grazing period. Nutrients in grasses and soils were analyzed. The dry matter yield during two-year experimental period was not different among mixtures (11,000-12,000 kg/ha/year). In botanical composition, perennial ryegrass was dominant in all mixtures during spring through early summer season, but faded away during hot summer season. Timothy seemed to be more resistant against a hot or dry weather than other grasses. The percentage of grasses intakes was higher in the mixture of timothy than those in other mixtures. The contents of NDF (neutral detergent fiber) and ADF (acid detergent fiber) were not different among different mixtures. These results indicate that the mixture of timothy, orchardgrass, perennial ryegrass and white clover (20, 5, 5, 2 kg/ha as a seeding rate) can be used for gazing pasture of horses in the high altitude of Jeju.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.390-401
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• 2006

This study was conducted to understand the phytoplankton-zooplankton trophic linkage in Lake Paldang ecosystems (Paldang Dam and Kyungan Stream) from April to December 2005. Zooplankton were filtered as two size groups (microzooplankton (MICZ): 60{\sim}20\;{\mu}m$, macrozooplankton (MACZ): >$200\;{\mu}m$), and their clearance rates and C-fluxes on phytoplankton were measured. Grazing experiments were performed in the laboratory with the different zooplankton densities (0, 2, 4, 8x of ambient density, n=2). Diatoms, such as Aulacoseira and Cyclotella were dominant phytoplankton taxa at both sites. Among phytoplankton communities, total carbon biomass of phyflagellates was much higher than others at both sites. Rotifers numerically dominated zooplankton community, while cladocerans dominated carbon biomass. Both phytoplankton and zooplankton density and biomass were high in spring, but decreased markedly after summer monsoon season. plankton biomass at Kyungan Stream was significantly higher than that of Paldang Dam. Zooplankton clearance rate and amount of C-flux were relatively high in the spring and then decreased after summer at both sites. Seasonal change of C-flux was similar to that of zooplankton biomass (P<0.001, n=7). MACZ clearance rate and C-flux were higher than those of MICZ. Water residence time and physical disturbance in summer appeared to affect zooplankton grazing on phytoplankton at the study sites. Our results indicate phytoplankton were an important energy source for zooplankton in Lake Paldang ecosystem. Furthermore, C-flux of plankton food web is affected by not only biological components but also physical parameters.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.515-519
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• 2009

Antibodies to Anaplasma phagocytophilum and Ehrlichia chaffeensis were detected by the immunofluorescent antibody (IFA) test in sera collected from cats, thoroughbred horses and Holstein cattle in Gwangju, Jeonju and Jeju Island of Korea. Two hundred fifty four sera (33 feral and pet cats, 92 grazing horses and 129 grazing cattle) were obtained from Republic of Korea. Antibodies to A. phagocytophilum (titer $\geq$ 80) were detected in 6 of the 33 feral and pet cats (18.2%), and 1 seropositive cat (3.0%) also had antibodies to E. chaffeensis. Only 1 of 129 (0.8%) cattle and 2 of 92 (2.2%) horses had antibodies to A. phagocytophilum. Antibodies to E. chaffeensis were not detected in either of these animals. This is the first report of serological evidence of A. phagocytophilum and E. chaffeensis from cats, cattle and horses in Korea. These rickettsial agents could have an important impact on human health or impact animal health with economic losses among industrial grazing animals in Korea.

• The Journal of the Acoustical Society of Korea
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• v.32 no.2
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• pp.95-103
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• 2013

An underwater acoustic (UWA) communication in shallow water is strongly affected by the water surface and the seabed acoustical properties. Every reflected signal to receiver experiences a time-variant scattering in sea surface roughness and a grazing-angle-dependent reflection loss in bottom. Consequently, the performance of UWA communication systems is degraded, and high-speed digital communication is disrupted. If there is a dominant signal path such as a direct path, the received signal is modeled statistically as Rice fading but if not, it is modeled as Rayleigh fading. However, it has been known to be very difficult to reproduce the statistical estimation by real experimental evaluation in the sea. To give an insight for this scattering and grazing-angle-dependent bottom reflection loss effect in UWA communication, authors conduct experiments to quantify these effects. The image is transmitted using binary frequency shift keying (BFSK) modulation. The quality of the received image is shown to be affected by water surface scattering and grazing-angle-dependent bottom reflection loss. The analysis is based on the transmitter to receiver range and the receiver depth dependent image quality and bit error rate (BER). The results show that the received image quality is highly dependent on the transmitter-receiver range and receiver depth which characterizes the channel coherence bandwidth.

• Korean Journal of Veterinary Service
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• v.14 no.2
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• pp.104-109
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• 1991

Tile present study was carried out to investigate the incidence of bovine brucellsis in Cheju-do during the period from 1985 to 1990. The results were summarized as follows. 1. In the total 239,238 cattles tested. 1180(0.49%) were positive by standard tube agglutination test during the period from 1985 to 1990. 2. The major causes of incidence on brucellosis was grazing with carriers and repeated incidence in a herd. 3. The 13 Brucella abortus biotype 1 isolated from 10(50％) of 20 cattles slaughtered on brucellosis in 1990.