• Asian-Australasian Journal of Animal Sciences
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• 제25권5호
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• pp.738-748
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• 2012

One of the main goals of small, medium and large farms is to improve the reproductive performance of rabbit does. Stocks of lower productivity can be improved by crossing with intensive breeds. A better nutritional status of both foetuses and suckling kits has a positive effect on their later productivity. Overfeeding young females before first mating can lead to conditions of fattiness. Using restricted feeding or higher fibre content in the feed and changing it for a higher level ad libitum feeding about one week prior to first mating leads to longer lifespan and higher productive level. Intensive reproductive rhythm creates a negative energy balance in does : they are unable to consume enough feed (energy) for the nutritional requirements of foetus and lactation, and therefore lose most of their fat reserves. Furthermore, primiparous does also expend energy because they are still growing. Under intensive conditions, the 42-d reproductive rhythm (re-mating 11 days after parturition) is recommended. Under extensive conditions, the 18 or 25-d mating interval with 35 to 42-d weaning could be suitable. On small farms, natural mating is favoured; on large farms AI is commonly employed. The main advantage of AI is the all-in, all-out system. Hormonal (PMSG) treatment is used with AI to increase receptivity on d 11. Frequent and high level PMSG use can lead to higher anti-PMSG antibody rates. Lower level (max. 20 IU) and less frequent PMSG injection or non-hormonal alternative methods (short dam-litter separation, changing nursing method or lighting programs) are recommended for this reason.

• 한국양식학회지
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• 제22권1호
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• pp.16-22
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• 2009

한국산 가재 Cambaroides similis 자연 개체군의 생활사를 밝히기 위해 2006년 3월부터 10월까지 약 8개월간 서울소재 관악산에 서식하는 가재를 조사하였다. 조사기간 중 포획 및 재포획 방법을 사용하여 총 551개체에 대한 조사가 이루어 졌다. 연구결과 관악산의 가재 개체군은 체장 빈도 분포를 통해 4개의 연령 구조를 가지는 것으로 추정되며, 암수 성비는 거의 동일하였다. 성장률은 수은에 크게 영향을 받음을 알 수 있었다. 6월에 확인된 어린 유생들은 8월에 성체로 성장하였다. 논란이 있었던 한국산 가재의 교미시기는 늦은 가을부터 시작됨을 확인하였다.

• 한국동물생명공학회지
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• 제36권4호
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• pp.247-252
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• 2021

Embryo transfer (ET) in the animal is an important procedure to generate genetically engineered animals and conserve genetic resources. For ET experiments in mice, pseudopregnant recipients are usually prepared with proestrus stage of females and vasectomized males. However, this conventional method is inefficient because the size of female colonies should be large to select only the proestrus stage in the estrous cycle and the surgical procedures are required to generate vasectomized males. In this study, we established a simple and efficient protocol to prepare ET recipients using the estrous synchronization with hormone injection and the mating with wild male mice. The delivery rate of ET recipients tended to be increased with estrous synchronization using hormone injection (100%) compared to the conventional method (71%). Further, natural pregnancy of the recipients, induced by mating with a wild male, significantly enhanced the birth rate of ET offspring than the conventional method (33% vs. 13%). Based on the results, we concluded that our new protocol using hormone injection to ET recipients and mating with wild males could be more efficient and simpler compared to the conventional method.

• 한국버섯학회지
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• 제15권3호
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• pp.111-117
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• 2017

본 연구는 밀리타리스 동충하초의 교배형 유전자인 MAT1-1과 MAT1-2 두 종류에 특이적인 프라이머를 사용하여 multiplex PCR을 실시하였고, 그 결과 형성된 MAT1-1과 MAT1-2에 대한 233-bp와 191-bp에서 DNA 밴드를 통해 교배형 및 교배여부를 확인하였고 자실체 특성검정을 통해 품종특성이 우수한 새로운 동충하초 '도원홍초 2호'를 개발하였다. 신품종 '도원홍초 2호'의 자실체는 곤봉형이고 밝은 주황색을 띠었으며, 코디세핀 함량은 0.33%였고 자좌의 굵기와 길이는 각각 3.5 mm와 7.1 cm였다. '도원홍초'와 비교할 때, 새로운 '도원홍초 2호'의 수량은 7%가 증수되었고 경도가 높은 특징을 보였다. 균사생장의 적온은 $20{\sim}25^{\circ}C$였고 버섯 발생의 적온은 $18{\sim}22^{\circ}C$였으며, 접종에서부터 자실체 발생까지의 기간은 49.7일이 소요되었다. 신품종 '도원홍초2호'는 교배형 분자마커를 육종과정에 이용하여 효율성을 높였으며, 우수한 재배적 특성으로 동충하초 인공재배 및 산업적 생산에 기여할 것으로 판단된다.

• Biomolecules & Therapeutics
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• 제4권4호
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• pp.297-300
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• 1996

LBD-001, a recombinant human interferon $\gamma$ produced by genetically engineered yeast as a host system, was administered intraperitoneally to Sprague-Dawley male rats from premating to mating period at least for 60 days and to female rats from at least for 2 weeks before mating to early gestation period (from day 0 to 7 of gestation) at dose levels of $0.35\times10^6, 0.39\times10^6, and 1.38\times10^6$ I.U./kg/day. In the positive control group, ethynylestradiol ($EE_2$; 40 $\mu\textrm{g}$/kg/day) was subcutaneously administered only to female rats during the early gestation period. Effects of the test agents on reproductive performances of the male or female rats and embryonic development were as followings; (1) No significant changes by the treatment of LBD-001 were observed in general behaviors, body weight, food and water consumption, and necropsy of parent animals. However, significant decreases of body weight, food consumption, and water consumption were observed in ($EE_2$ -treated female rats. (2) Mating performances and fertility of parent animals were not significantly affected by the treatment of LBD-001. In ($EE_2$ -treated females, however, the fertility was completely inhibited. (3) No changes in resorption rate and external abnormality of F1 fetuses were observed by the treatment of LBD-001. The results show that LBD-001 at the dose of $1.38\times10^6$ I.U./kg/day or less does not affect general toxicity and reproductive function of parent animals and embryonic development of F1 fetuses.

• 한국양봉학회지
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• 제33권4호
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• pp.251-260
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• 2018

Instrumental insemination of honey bee is an attractive alternative to natural mating in breeding program as it allows mating crosses between desirable queen and specific drone. However, nursery condition that the queen is kept before and after insemination is major factor affected to the performance of instrumentally inseminated queen. In this study, we evaluated the influences of three different nursery-conditions of push-in cages, mini nuclei and normal colonies on number of spermatozoa stored in the spermatheca, body weight, onset of ovipositon and performance of instrumentally inseminated Apis cerana queen. Our results demonstrated that instrumentally inseminated queens kept in mini nuclei and in normal hives showed no significant difference in queen's weight (159.8 and 166.2mg, respectively), number of spermatozoa in spermatheca ($2.02{\times}10^6$ and $2.76{\times}10^6$, respectively), proportion of queen supersedure (33.3 and 66.7% queen survival at 11 months after oviposition, respectively) and brood production, compared to naturally mated queens. In contrast, instrumentally inseminated queens kept in push-in cages showed significant difference of those above data in comparison to queens mated naturally. Our results suggested that instrumentally inseminated queens could be kept in mini nuclei containing about 1.000 attendant bees to have desirable performance of queen whereas the push-in method should be practiced for the purpose of using queen in the length of time less than 7 months.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.294.1-294
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• 1999

No Abstract, See Full Text

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.163-170
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• 2001

Axle Gearbox of the High Speed Train has rotational degree of freedom centered on the Axle Shaft Center Line, and constrained by the Reaction Arm connected to the Bogie Frame via Resilient Ring made of Rubber. This System is laid on the Power Train and can influence on the Power transmitted from Motor to Axle. The stiffeness of the Resilient Ring have to be selected for the Natural Frequency of this System do not overlap with the Teeth-mating Frequency. To confirm the Design Parameters, Calculation and Experiment were executed and compared.

• 드라이브 ㆍ 컨트롤
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• 제14권1호
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• pp.1-7
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• 2017

The power train of a concrete truck mixer reducer includes differential planetary gears to get a large reduction ratio for operating the mixer drum in a compact structure. These differential planetary gears are a very important part of the mixer reducer where strength problems are the main concern. Gear bending stress, gear compressive stress and scoring failure are the main concerns. Many failures in differential planetary gears are due to the insufficient gear strength and resonance problems caused by major excitation forces such as gear mating failure in the transmission. In the present study, where the excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate differential planetary gear critical speeds. Mode shapes and natural frequencies of the differential planetary gears are calculated by CATIA V5. These are used to predict gear resonance failures by comparing the working speed range with the critical speeds due to the gear transmission errors of the differential planetary gears.

• 드라이브 ㆍ 컨트롤
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• 제14권4호
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• pp.71-78
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• 2017

The power train of hydro-mechanical continuously variable transmission (HMCVT) for 8-ton class forklift includes hydro-static units, hydraulic multi-wet disc brake & clutches and complex helical & planetary gears. The helical & planetary gears are key components of HMCVT's power train wherein strength problems are the main concerns including gear bending stress, gear compressive stress, and scoring failure. Many failures in power train gears of HMCVT are due to the insufficient gear strength and resonance problems caused by major excitation forces, such as gear transmission error of mating gear fair in the transmission. In this study, wherein excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate the power train gears' critical speeds. Mode shapes and natural frequencies of the power train gears are calculated by CATIA V5. These are used to predict resonance failures by comparing the actual working speed range with the critical speeds due to the gear transmission errors of HMCVT's power train gears.