• Reproductive and Developmental Biology
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• v.29 no.1
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• pp.25-30
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• 2005

This study was carried out to investigate the effects of semen characteristics, frozen-thawed sperm viability and serum FSH, LH, estradiol-17β and testosterone concentrations between breeds and among seasons in boars. In all seasons, Yorkshire boars produced higher semen volume compared with Duroc boars, whereas sperm concentration did not differ significantly between Duroc and Yorkshire boars. Semen volume in spring was higher compared with summer, autumn and winter in both Duroc and Yorkshire boars, but sperm concentration did not differ significantly among seasons. Sperm motility and normal acrosome rate of frozen-thawed sperm produced in spring were higher than those in summer, autumn and winter in both Duroc and Yorkshire boars. Sperm motility of frozen-thawed sperm in Yorkshire boars was higher than that in Duroc boars regardless of seasons. However, normal acrosome rate did not differ significantly between Duroc and Yorkshire boars. Serum FSH concentration in Yorkshire boars was lower than that in Duroc boars in all seasons. However, there were no significant differences on serum FSH concentration of Duroc and Yorkshire boars among seasons. Serum LH and estradiol-17β concentrations did not differ significantly between Duroc and Yorkshire boars. Also, there were no significant differences in serum LH and estradiol-17β concentrations of Duroc and Yorkshire boars among seasons. Serum testosterone concentration in Yorkshire boars was higher than that in Duroc boars in all seasons. In both breeds, serum testosterone concentrations were higher in spring than in summer, autumn and winter. In conclusion, when serum FSH concentrations were low, semen volumes were high, and when serum testosterone concentrations were high, sperm motility and normal acrosome rate of frozen-thawed sperm were high.

• Korean Journal of Environment and Ecology
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• v.25 no.6
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• pp.828-835
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• 2011

This study was conducted to understand the characteristics of bird community, migration, nesting guild, ordination analysis of observed frequency of birds at Jeju Experimental Forests (JEFs) from November 2006 to September 2007 with surveys of two areas by line transect methods and point-count methods at five areas for three consecutive days in each month. Among observed 58 species could be classified into the 24 residents, 9 summer visitors, 9 winter visitors and 16 passage migrants according to migration habit. In species composition, passage migrants are dominant birds at study areas whereas summer and winter visitors are most dominant birds at mainland's forests. We could divide two groups of bird community in the view of monthly species composition, one is November to February group, the other March to July group by ordination analysis. Number of species did not show seasonal fluctuation which is common pattern of bird community in mainland. This pattern reflects that species composition can change during breeding and non-breeding periods, but overall number of species did not change. This can be related with the high use of passage migrants at study area, also suggests that the JEFs can be highly utilized as stopover sites during migration. At mainland's forests, we can observe about five species of woodpeckers, however we just observed the only one species of White-backed Woodpeckers (Dendrocopos leucotos) at study areas. In the view of nesting guild, breeding birds can be grouped into the 9 bush-& ground nesters, 8 canopy nesters, 7 hole nesters and one house nesters. Among hole nesters, we can observe only one species of primary cavity nesters White-backed woodpecker, and the five secondary cavity nesters, that is three species of tits, tricolor flycatchers (Ficedula zanthopygia) and ruddy kingfishers (Halcyon coromanda). Therefore, White-backed woodpeckers can be regarded as a keystone species and forest practice should consider the careful conservation of this species.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.3
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• pp.36-45
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• 2006

By analyzing the sea surface temperature (SST), chlorophyll ${\alpha}$, zooplankton and Orview/SeaWiFS satellite data in the Korean Waters from 1999 to 2001, we studied the seasonal and annual variation of chlorophyll ${\alpha}$ concentration and zooplankton biomass. Sea surface temperature was fluctuated with the typical seasonal variation in the waters of temperate zone. Chlorophyll ${\alpha}$ concentration and zooplankton biomass were high in spring and autumn. Year to year fluctuations on annual averaged chlorophyll ${\alpha}$ concentrations in Korean Waters in the spring from 1999 to 2001 were decreased continuously. On the other hand, the estimated chlorophyll ${\alpha}$ concentrations derived from SeaWiFS ocean color data were lower than the measured sea surface chlorophyll a in the Korean Waters.

• Feed Journal
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• v.4 no.7 s.35
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• pp.108-115
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• 2006

우리나라는 사계절이 뚜렷한 기후적 환경으로 여름철 한낮의 외부온도가 35℃ 이상이 되는 날이 계속되고, 야간에도 25℃ 이상인 열대야가 지속되는 날이 많다. 이러한 조건하에서 양돈 생산성 향상을 위해서는 돼지의 사육환경과 성장단계별 적절한 사양기술을 투입하여야만 한다. 돼지는 생리적으로 추위에 의한 영향보다는 여름철 더위에 의한 영향을 쉬게 받으며, 이로 인해 자돈의 쇠약, 압사,수태율 저하, 번식장애 등으로 생산성 저하의 원인이 되며, 사육기간 중에 일시적인 고온스트레스가 돼지가 생존하는 동안 능력의 저하를 초래하게 된다. 특히 하절기 양돈장은 우기와 무더위로 인한 돈사내 온도의 급상승과 더불어 습도의 불균형에 의한 환경적 스트레스로 번식능력과 생산성에 크게 영향을 미칠 수 있으며,돼지에 일시적인 고온 스트레스 피해는 장기간 계속되며, 생존하는 동안 능력저하를 초래하기 때문에 농장별 사육여건에 따른 성장저해 요인을 제거하는 안목이 필요한 계절이다. 즉,5~9월 모돈에 고온스트레스가 가해지면 11~12월, 다음해 1월 모돈의 분만율은 최저가 되고 , 이 시기에 생산된 자돈은 추운겨울을 이겨내야 함으로 육성률도 낮아지며, 이로 인해 4~7월의 출하성적은 최저가 되는 것이다. 따라서 모돈 관리는 5~9월이 집중관리가 필요한 시기이기도 하다. 고온 다습한 환경 하에서 어미돼지는 영양불균형과 생체리듬의 파괴로 인하여 신생자돈의 폐사가 증가할 수도 있고,이유 후 1주일 이내 발정 재귀율이 약 30%정도 감소하고 무발정돈이 많이 발생되며, 수태가 되어도 조기 배아사멸 및 흡수로 인하여 수태율이 25%까지 감소될 수 있다. 현재 국내 양돈농가에는 예년과 같이 돼지 조모성질환의 발생이 늘어나고 있고, 어려움을 겪고 있는 농장이 많은 것으로 조사 보고되어지고 있는데, 이는 농장에 사육되는 돈군이 외부환경에 대한 적응능력과 질병에 저항력이 부족하여 쉽게 질병에 노출되어 발생함으로 농장에는 돼지가 스트레스를 받지 않게 외부 환경과 사양관리 측면에 심혈을 기울려 강건한 축군을 유지하려는 노력이 무엇보다 우선되어져야 한다고 생각된다. 따라서 본고에서는 여름철에 돼지 스트레스를 줄이고 생산성을 향상시키기 위해 돼지의 생리변화와 돈사 급수설비와 사료관리 및 사육관리에 대해 알아보고자 한다.

• The Korean Journal of Ecology
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• v.25 no.3 s.107
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• pp.179-187
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• 2002

This study was conducted to clarify the characteristics of attitudinal bird communities in Mt. Seoraksan National Park from May to Oct. 2004. Marsh tit Parus palustris, Arctic warbler Phylloscipus borealis, coal tit Parus ater and Eurasian nuthatch Sitta europaea evenly distributed in almost elevational ranges. Goshawk Accipiter gentilis, black grouse Tetrao tetrix, white-lumped swift Apus pacificus, Siberian rubythroat Luscinia calliope, red-flanked bluetail Tarsiger cyanurus, dusky warbler Phylloscopus fuscatus, yellow-browned warbler Phylloscopus inornatus, siskin Carduelis spinus and rook Corvus frugilegus were only observed in high altitude area. Distribution pattern of birds in Mt. Seoraksan National Park showed differences by elevation. There was difference in attitudinal distribution pattern of birds in Mt. Seoraksan National Park. It seems that habitat preference or selection is different in each species. Attitudinal habitat preference of each bird species need further studies.

• The Korean Journal of Ecology
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• v.25 no.2
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• pp.109-117
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• 2002

This study was conducted to clarify the characteristics of attitudinal bled communities in Mt. Seoraksan National Park from May to Oct. 2001. Marsh tit Parus palustris, Arctic warbler Phylloscipus borealis, coal tit Parus ater and Eurasian nuthatchh Sitta europaea evenly distributed in almost elevational ranges. Goshawk Accipiter gentilis, black grouse Tetrao tetrix, white-rumped swift Apus pacificus, Siberian rubythroat Luscinia calliope, red-flanked bluetail Tarsiger cyanurus, dusky warbler Phylloscopus fuscatus, yellow-browned warbler Phylloscopus inomatus, siskin Carduelis spinus and rook Corvus frugilegus were only observed in high altitude area. Distribution pattern of birds in Mt. Seoraksan National Park showed differences by elevation. There was difference in altitudinal distribution pattern of birds in Mt. Seoraksan National Park. It seems that habitat preference or selection is different in each species. Altitudinal habitat preference of each bird species need further studies.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.95-101
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• 2014

This study was conducted to analyze the pattern of growth and phenological characteristics of Mankyua chejuense B.-Y. Sun, M.H. Kim & C.H. Kim, which belong to the Ophioglossaceae family. M. chejuense asexually reproduced using rhizomes, and a clone of the species grew up to 52 cm based on root growth and new leaves was produced from rhizomes. The development of leaves were divided into four stages; leaf emergence-separation and growth of leaf-sporophyll maturation-senescence. Most leaves emerged in July and August with high temperatures and precipitation and most leaves reached full expansion during September-October and died during April-May next year. The life span of leave was 10 months, from July to April, and the start of leaf senescence varied depending on the habitat environment and this might result from micro environmental differences among the habitats.

• Korean Journal of Animal Reproduction
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• v.5 no.2
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• pp.35-42
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• 1981

A total 2,488 ejaculates during 4 years from 80 Korean native bulls over the age from 3 to 12 years of bull herds of Artificial Breeding Center, National Livestock Federatives Cooperation were collected and analyzed to study the effects of collection year, age of bulls, month of years, collection interval and ejaculation frequency per day on semen volume, sperm concentration, total sperm per ejaculate and sperm motility. 1. Semen volume, sperm concentration, total sperm per ejaculate and sperm motility index for the all ejaculates using least squares procedure averaged 5.73ml, 9.133${\times}$108/ml, 52.527${\times}$108 and 62.81, respectively. 2. Semen volume varied significantly with collection year, collection interval and ejaculation frequency per day(P<0.01), but effects of age of bulls and month of years on semen volume were not significant. Eight to 15 days collection interval showed the highest volume, and 1st ejaculate contained 5.6% more volume than 2nd ejaculate. 3. There were significant differences among collection years, months of years and ejeculation frequencies per day except collection intervals in sperm concentration per ml(P<0.05, P<0.01). Six to 8-year-old bulls was the highest concentration. Higher sperm concentration per ml was in April to July and lower month was October and December. Sperm concentration in 2nd ejaculate was higher than in 1st ejaculate. 4. Total sperm per ejaculate affected by all environmental factors studied(P<0.05, P<0.01). Age of bulls, collection interval and ejaculation frequency per day showed the highest total sperm was 6 to 8-year-old bulls, 8 to 15 days interval and 1st ejaculate, respectively. Higher total sperm per ejaculate was in April to July and lower total sperm was in September to December. 5. In sperm motility, there were significant differences among collection years, ages of bulls and collection intervals except months of years and ejaculation frequencies (P<0.01). Higher sperm motility was in 6 to 12-year-old bulls and in 5 to 7 days collection interval.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.47-51
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• 2007

The objective of this study was to improve the reproductive ability of Thoroughbred mares with artificial estrous regulation by hormone treatments and artificial illumination. The results were as follows; Estrous detection in cycling mares which were treated $PGF_2{\alpha}$ or altrenogest administration was all 100%, and pregnancy rates were 95.2% and 71.4%, respectively. Estrous detection was 100% within March when altrenogest was administered alone or together with estradiol for non-pregnant mares in the previous year. Interval to estrous detection after altrenogest administration was 4.3 days in single administration of altrenogest and 3.7 days in combined administrations of altrenogest and estradiol, respectively Interval to ovulation after estrous detection were 2.7 and 2.5days, respectively. Pregnancy rate following single altrenogest administration was 80.0%. Estrous detection and pregnancy rates by artificial illumination in non-pregnant mares were 92.9% and 46.9%, respectively. These results show that estrous synchronization of mares during breeding season will be able to improve the pregnancy rate, and altrenogest administration in non-pregnant mares in the previous year will be able to induce early reproduction and improve pregnancy rate In racing horses.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.79-90
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• 1991

This study was conducted to investigate seasonal avifauna and to suggest a proper way how to manage and protect wild birds in Chirisan National Park. The survey was carried over 3 main trail districts by line transect method to figure out influence factor of inhabitation of wild birds from February to November in 1991. The study results are as follows : The observed birds were belong to 6 orders 24 families 49 species and 981 individuals and Falco tinnunculus(Natural monument No. 323). These birds also classified into 24 species for residents, 12 species for summer visitor. 9 species for winter visitor, 4 species for passage migrant, respectively. The observed average frequeney of birds was 2.09e.a./ha, and main dominant species were Parus varius, Parus major, Emberiza elegans, Garrolus glandarius, Sitta europaea, Hypsipetes amaurotis, Parus palustris in order. Cheoneun-sa trail route showed relatively decreasing trend of wild birds during spring and fall season because of the highest trail use of visitors. Maximum frequency of species and individuals appeared at Hwaum-sa route in spring and at Piagol route in fall. respectively. Those regions well explained the advantageous inhabitation area of birds in both regions. The diversity index of birds in winter showed little difference of similarity index due to balanced use of trails. Seasonal low similarity index in those 3 main trail district indicate a dissimilarity of environmental factors. Trail use restriction as a provision of proper management and protection of wild birds have to be made at Hwaum-sa route where propagation of birds actively occurred in spring and at Piagol route where birds wintering were observed will contribute to enhance species diversity in the future.