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        검색결과 30

        1.
        2024.04 구독 인증기관·개인회원 무료
        깡충거미과의 모습을 의태하여 시각적 포식자인 깡충거미로부터 자신을 보호하는 전략은 여러 나비목 곤충 에서 진화하였다. 하지만 나비목 곤충이 깡충거미 간의 의사소통 신호를 의태한다는 가설은 제안된 바 없다. 본 연구에서는 깡충거미과의 구애/영역성 행동을 의태하는 것으로 추정되는 붉은꼬마꼭지나방(Atkinsonia ignipicta)의 빗살 모양 더듬이와 추켜 올린 다리가 포식을 단념시키는 의태 신호로 작동하는지 실험적으로 검증 하였다. 깡충거미 의태라 추측되는 붉은꼬마꼭지나방의 형태적 및 행동적 특성들을 단계적으로 제외한 뒤 포식 자(흰눈썹깡충거미, Evarcha albaria)와의 조우 시 생존을 비교하였다. 연구 결과, 붉은꼬마꼭지나방은 비슷한 크기의 비-의태 나방에 비해 포식자의 공격을 덜 받았으며, 더듬이나 다리 중 하나라도 결여되었을 때 흰눈썹깡충 거미의 공격이 증가하였다. 이는 붉은꼬마꼭지나방의 더듬이와 다리 모두가 시각적 방어의 중요한 신호로 작동 한다는 것을 시사한다. 하지만 흰눈썹깡충거미가 붉은꼬마꼭지나방을 향해 구애/영역성 행동을 보이지 않았다 는 점에서 깡충거미의 낮은 공격 빈도가 같은 깡충거미 종류로 오인해서인지 다른 이유에서인지는 불투명하다. 그러나 사층깡충거미(Marpissa pulla)는 붉은꼬마꼭지나방을 상대로 영역성 행동을 잦은 빈도로 보였으며, 이는 붉은꼬마꼭지나방의 형태가 깡충거미 의태 효과를 가진다는 것을 보여준다.
        2.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The sheep can be reproduced by natural mating as well as applied reproductive biotechnology, embryo transfer (ET). However, this method in sheep is influenced by several factors such as season, photoperiod, latitude, temperature, nutrition, and breed. In addition, there is still less research on assisted reproductive technologies in small ruminants, compared to other livestock species such as cattle and pigs. Because there has been a need for an optimization and a continuous improvement of ET techniques in small ruminants. the main objective of this study was to evaluate the conception rate obtained after ET in Mongolian sheep (Dorper breed). After embryo recover, code 1 and 2 embryos (morula or blastocyst stage) for ET in the present study were 63% (63/100) and 24% (24/100), respectively. Then Each single embryo was transferred to a synchronized recipient who prepared by estrous synchronization protocol with fluorogestone acetate-cloprostenol sodium. The results demonstrated that an average conception rate and lambing rate was 35.6% (31/87) and 33.3% (29/87), respectively. Further study is still necessary, but these results indicated that single embryo of Mongolian sheep with the present protocol was enough to conducting ET when the genetically superior sheep were necessary to be expanded.
        4,000원
        3.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Diets different in crude protein (CP) and undegraded intake protein (UIP) contents were offered to sheep in a metabolism study to describe their effects on nutrient digestibility and nitrogen (N) metabolism. Six Corriedale sheep (body weight=56.2±2.3 kg) were divided in random within a Latin square design (replicated) to 1 of 3 diets: 1) a low-CP diet (LP; 12.2% CP with 35.1% UIP), 2) high CP with low UIP diet (HPLU; 14.9% CP with 33.7% UIP), and 3) high CP with high UIP diet (HPHU; 15.5% CP with 45.8% UIP). High-protein dried distillers grain and soybean meal were the main CP sources for the adjustment of UIP:DIP in the diets. No significant differences were found in feed consumption and nutrient digestibility; however, a greater proportion of CP was digested in sheep fed the HPLU diet (69.4%; P=0.04). Although N intake was greater in sheep receiving HPLU and HPHU diets, loss of N through fecal or urinary route was not different among sheep, which resulted in the highest (12.7 g/d) and lowest N retention (7.40 g/d) in HPHU- and LP-fed sheep, respectively. In conclusion, although CP or UIP content had marginal effects on feed consumption and whole-tract digestibility of the majority of nutrients, with the increased CP and UIP levels in the diet, the efficiency of N utilization was improved with regard to increased N retention with minimal differences in N excretion, which is important from an economic and environmental standpoint.
        4,000원
        4.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Food and agricultural production sector, especially livestock production is vital for Mongolia’s economic and social development. Domestic sheep play key roles for Mongolians, providing food (meat, milk) and raw materials (wool, sheepskin), but genetic diversity, origin of sheep populations in Mongolia have not been well studied. Studies of population genetic diversity is important research field in conservation and restoration of animal breeds and genetic resources. Therefore, this study aimed to investigate genetic characteristics and estimate origin through the analysis of mitochondrial DNA control region D-loop and Cytochrome b of Mongolian indigenous sheep (Mongolian native, Orkhon and Altanbulag) and one Europe sheep (Suffolk). As a result of there were found, 220 SNPs (Single nucleotide polymorphism) in the D-loop region, 28 SNPs in the Cytochrome B region, furthermore, 77 Haplotypes. The nucleotide diversity was only found in D-loop region (n = 0.0184). Phylogenetic analysis showed that 3 (A, B, and C) of 5 haplogroups of sheep have been identified in our research. Haplogroup C was only found in Mongolian indigenous sheep. Haplogroup D and E were not observed. As a result of haplogroups, haplogroup A was dominant (n = 46 of 94 sheeps), followed by haplogroup B (n = 36) and haplogroup C (n = 12). Sequence analysis showed that T deletion, insertion and heteroplasmy in D-loop region occurred at a high rate in Mongolian indigenous sheep population (T insertion = 47, T deletion = 83). The heteroplasmy, which has never been found in Mongolian sheep, has been newly discovered in this study. As a result, the Mongolian sheep varieties, which mainly derived from Asia, were in hybridization with European sheep varieties.
        4,000원
        5.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the current study was to compare the effects of season and breed on the reproductive performance of male and female sheep using 12 rams and 318 ewes of Assaf and Awassi breeds under the seasonal environmental condition of United Arab Emirates for two years. The blood level of testosterone hormone was measured monthly. Semen was collected twice a month from each male using artificial vagina and evaluated for volume, motility, livability, abnormality and concentration. The scrotal circumference and thickness as well as the left testicular length, width, height and volume were measured at one-month intervals. The level of testosterone in Assaf breed was significantly higher in autumn than winter and summer. The scrotal circumference and thickness as well as the left testicular length were significantly higher in Assaf breed than Awassi breed. While, left testicular width and volume were significantly higher in Awassi breed than Assaf breed. Scrotal circumference which was higher in spring and summer than in autumn and winter season in both breeds. The SCC of semen was significantly higher in autumn than in other seasons in both breeds. The sperm abnormality was significantly higher in summer than other seasons in both breeds. The livability was significantly lower in summer in both breeds. Fecundity and prolificacy were significantly higher in Assaf than Awassi breed during autumn season. Assaf breed showed the superior reproductive performance in the autumn season when compared with Awassi breed in the same season and other seasons. The Assaf breed tolerated the climatic conditions in UAE and kept the litter size of 1.72 in comparison to Awassi breed which showed litter size of 1.09. in conclusion, the results showed the superiority of Assaf over Awassi breed and offer a good model of breeding with increased fecundity and prolificacy specially in autumn season.
        4,000원
        6.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 필립 케이 딕의 과학소설『안드로이드들은 전기 양을 꿈꾸는가?』와『유빅』에서 나타난 SF적 상상력과 종교적 비전을 고찰하는데 있다. 딕은『안드로이드』와『유빅』에서 우리의 세계가 고도의 과학기술과 자본주의로 인해 인간의 탐욕과 불안으로 가득 찬 엔트로피적 세계임을 비판하면서 이것을 해결하기 위한 대안으로 ‘머서주의’와 ‘유빅’이라는 종교적 비전을 제시한다. 딕은 작품에서 ‘머서주의’를 통해 인간 본성의 선과 악을 인정하고 인간 존재의 불완전함을 받아들이고 극복해야 한다고 주장한다. 감정이입을 기반으로 하는 머서주의는 선과 악의 극단적인 대립을 강조하는 전통적 종교의 경직된 사고를 해체하고 자신과 타자의 경험 공유를 통해 자기 구원을 선언할 수 있음 을 재현한다. 또한 로고스로 확인되는 유빅을 통해 구원의 가능성을 제시한다. 이를 통해 딕은 신성은 거룩한 교회나 성소에만 존재하는 것이 아닌 주변과 일상의 삶에서 발견될 수 있음을 이야기하며 종교의 의미가 단순히 믿음의 문제 뿐만 아니라 인간 존재와 공동체적 가치를 실현하는 궁극적인 신념임을 제시한다.
        5,800원
        7.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to evaluate the accuracy of equation being used to estimate the total digestible nutrients (TDN) of whole crop rice silage (WCRS) in sheep. To compare the observed and estimated TDN contents [estimated TDN content=87.57-(0.737×ADF)], two varieties of WCRS from Nokyang (NS) and Samgwang (SS) as forage and food source, respectively, were used as a treatment. Nine female Corriedale sheep (average body weight: 49.2±6.3 kg) were used as the experimental animals. The ewes were fed according to their nutrient requirements at the maintenance level. To check the difference between the observed and estimated TDN contents, one sample non-parametric t-test was applied. The CP, NFE and CF contents of the NS were 43.6, 74.2 and 64.2%, respectively, and that of the SS were 46.2, 58.1 and 44.9%, respectively. The observed and estimated TDN contents of the NS were 63.5 and 61.5%, where there was no significant difference. The observed and estimated TDN contents of the SS were 48.9 and 59.0%, where there was significant difference (p<0.05) This research confirmed the validity of TDN estimation equation being used for estimation of TDN of WCRS as forage source, but further research is recommended on the equation for estimating TDN contents of WCRS as food source.
        4,000원
        9.
        2012.06 구독 인증기관·개인회원 무료
        Interferon-tau (IFNT) is regarded, generally, to be the conceptus protein that signals maternal recognition of pregnancy in ruminants. Although the discovery was made over two decades ago, the molecular mechanisms that regulate IFNT expression are not well understood. Previous studies demonstrated that transcription factors, caudal-related homeobox- 2 (CDX2), JUN, ETS2 and a transcriptional coactivator CREB binding protein (CREBBP) positively influenced IFNT gene expression, while OCT4 may exhibit negative regulation. We and others have observed that both CDX2 and OCT4 coexist during early stages of conceptus elongation but as development proceeds, OCT4 expression diminishes. The objective of this study was to evaluate the stimulatory and inhibitory effects of CDX2 and OCT4, respectively, on IFNT gene transcription when evaluated with other transcription factors. Human choriocarcinoma JEG3 cells were co-transfected with an ovine IFNT (-654 base pair)-luciferase reporter (-654-oIFNT-Luc) construct and several transcription factor expression plasmids. When the reporter construct was co-transfected with either CDX2, ETS2 or CJUN, transcription of -654-oIFNT-Luc increased about two-fold compared to -654-oIFNT-Luc alone. When -654-oIFNT-Luc was co-transfected with both c-jun and Ets-2, activity of -654-oIFNT-Luc was increased about four-fold; cotransfection with JUN, ETS2 and CDX2 increased -654-oIFNT-Luc expression 12X, indicating that the stimulatory activity of the transcription factors was additive. OCT4, when cotransfected with -654-oIFNT-Luc, reduced expression of the later about 40% when compared to -654-oIFNT-Luc alone. When co-transfected with JUN and/or ETS2, OCT4 abolished the stimulatory effect of these transcription factors. OCT4 also inhibited the stimulatory activity of CDX2 alone, but not when CDX2 was combined with JUN and/or ETS2. Therefore, when combined with the other transcription factors, CDX2 over the transcriptional inhibitory activity of OCT4. Conversely, when cells were transfected initially with OCT4 (0h) followed by transfection with CDX2, ETS2 and JUN 24 h later, -654-oIFNT-Luc expression was reduced to control (-654-oIFNT-Luc, alone) levels. Not surprisingly, 12S E1A, an inhibitor of transcriptional coactivator CREBBP, reduced stimulation of -654- oIFNT-Luc expression by CDX2, ETS2 and JUN, in combination, by about 40%, indicating that proper transcription complex formation is required for maximum expression. In conclusion, it is suggested that prior to conceptus elongation, pre-existing OCT4 may inhibit IFNT expression, but as elongation proceeds, IFNT expression increases, resulting from incremental increases in CDX2 expression, diminished OCT4 expression, and possibly proper transcription factor complex formation. Key words) Interferon-tau, CDX2, OCT4, transcription
        10.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 sheep fescue 70%와 야생화 30%의 파종비율로 조성한 야생화초지의 생육특성, 계절분포 및 식생비율을 구명하고자 충남대학교 내 초지시험포장에서 2007년 10월부터 2009년 12월까지 수행하였다. 공시초종은 기본초종인 잔디형 목초로 sheep fescue (Azure)와 국내산 야생화 4종과 외국산 야생화 29종 등 총 33종을 공시하였다. 1년차(2008) 야생화의 개화당시의 평균초장은 1년차 29.9 cm, 2년차 38.4 c
        4,000원
        11.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 쉽 페스큐 50%와 야생화 50%의 파종비율로 조성한 야생화초지의 생육특성, 계절분포 및 식생비율을 구명하고자 충남대학교 내 초지시험포장에서 2007년 10월부터 2009년 12월까지 수행하였다. 공시초종은 기본초종인 잔디형 목초로 쉽 페스큐(Azure)와 국내산 야생화 4종과 외국산 야생화 29종 등 총 33종을 공시하였다. 야생화의 개화당시의 평균초장은 1년차 30.0 cm, 2년차 35.6 cm 이었다. 꽃 색은 10가지로 다양하게 개화
        4,000원
        12.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 쉽 페스큐 90%와 야생화 10%의 파종비율로 조성한 야생화초지의 생육특성, 계절분포 및 식생비율을 구명하고자 충남대학교 내 초지시험포장에서 2007년 10월부터 2009년 12월까지 수행하였다. 공시초종은 기본초종인 잔디형 목초로 쉽 페스큐(Azure)와 야생화 초종으로는 국내산 야생화 4종과 외국산 야생화 29종 등 총 33종을 공시하였다. 야생화의 개화 당시의 평균초장은 1년차 28.7cm, 2년차 36.7 cm 이었다. 꽃 색은 6~9
        4,000원
        14.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A necropsy of a primiparous, 4-year-old, Himalayan tahr (Hemitragus jemlahicus) was performed in September 8, 2009. Typical appearances of ovaries, oviducts, uterine horns, cervix and caruncles were well shown. Five cervical folds were present in the cervix. Cervical opening can be reached in the length of less than 15 cm from the entrance of vagina. Development of two follicles was found in the left ovary even though breeding season of this species naturally starts in late November. The reproductive organs of a primiparous, 3-year-old, Corriedale sheep showed that differences in the length and morphological appearance of cervix exist between two species. Comparative understanding of reproductive systems in Himalayan tahr and Corriedale sheep could help advancing assisted reproductive technologies in feral goats.
        3,000원
        15.
        2009.08 구독 인증기관·개인회원 무료
        Ingestion of plant secondary metabolites (PSMs) presents a major challenge to mammalian herbivores. We investigated the relationship between PSM concentrations in the diet and feeding patterns in sheep fed diet containing flavone extracted from Apocynum venetum. Results showed that the flavone concentrations significantly influenced food intake by sheep. With the concentration of flavone in diet increase, sheep can regulate their intake of PSM within limits that are tolerable.
        16.
        2009.08 구독 인증기관·개인회원 무료
        The objective of this study was evaluated the influences of the nitrogen fertilization level on timothy silage fermentation quality, nutritive value, and nutrient intake. In both the first and second crops, high level nitrogen fertilization (H) led to a lower WSC content and higher CP content than standard nitrogen fertilization (S). The silage fermentation quality was good in the presence of a Lactobacillus inoculant (SI and HI) than uninoculant (SC and HC). In the first crop silage, the TDN content and intake were significantly higher (P<0.01) for HI than for SI. In the second silage, the DM, DE, and TDN intakes did not significantly differ among the 4 treatments.
        18.
        2005.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 섬유소공급원 7종, alfalfa hay cube (AHC), corn cob (CC), corn silage (CS), cotton seed hull (CSH), peanut hull (PHL), rice straw(RS), sugar cane bagasse(SCB)의 반추위에서의 반추활동, pH, 완충능력과 전소화기관 내 소화율을 알아보고자 실시하였다. 공시 동물은 평균체중 37.1kg인 Corridale종 수 면양 5두 (3두는 반추위
        4,000원
        20.
        1999.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산지초지에서 애기수영의 생육제어를 위한 석회와 질소의 적정 시용수준을 추정하였다. 1. 애기수영의 모든 예취회수에서 질소시용수준간과 석회시용수준간에는 유의성이 인정되었다. 2. 석회 200~300kg/10a의 수준에서 질소 21kg/10a 이상을 시용하는 것이 설정하는 것이 애기수영의 생육제어를 위하여 효과적이었다. 3. 질소 16kg/10a의 수준에서의 애기수영의 연간 건물수량이 가장 많았다. 4. 질소 48kg/10a의 수준에서 석회 520.5kg/10a을 시용할 경우, 애기수영의 완전한 생육제어가 가능한 것으로 추정되었다. 5. 석회 200~300kg/10a의 수준에서 2회 예취와 4회 예취의 생육제어효과가 가장 높았다. 6. 질소 48kg/10a의 수준의 1회 예취, 2회 예취, 4회 예취에서 생육제어효과가 가장 높았다.
        4,000원
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