• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.226-230
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• 2022

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.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.17-23
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• 2000

The spatial distribution of allelic frequencies was studied in the natural population of three species (Ligustrum obtusiflolium, Alnus japonica, and Pinus densflora). The distributional patterns of the crown-cover centers were compared between two populations in forests. L. obtusifolium and p. densiflora showed a significantly positive spatial autocorrelation as measured by Moran's I. In P densiflora, the genetic similarity was shown by individuals within up to a scale of 18 m distance and this is partly due to combination of pollen dispersal and long distance seed dispersal by wind or men. In L. obtusifolium, population structure in the distribution of allelic frequencies is related to mating systems and is consisted of a scale of 12.5 m intervals. No spatial structuring of allele frequencies was found for polymorphic enzyme loci within a natural population of Alnus japonica. The results also in- dicate that positive associations between L. obtusifolium and P densiflora can occur when both select the same habitat or have the same environmental requirements.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.207-216
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• 2005

Spawning behaviors of Squalidus gracilis majimae (Cyprinidae) were observed in the laboratory whose environmental factors such as light (D/L = 16 : 8), temperature ($20\;{\sim}\;24\;＾{\circ}C$), and dissolved oxygen (>8 mg $L^{-1}$) were quite regularly controlled. The behavioral patterns were categorized into three stages ofpre-spawning, spawning, and Post-spawning behaviors. In Particular, the pre-spawning stage was specified by 11 specific behavioral patterns of aggressive mating behaviors. During the spawning stage, the male and female performed four distinct spawning behaviors including sexual temptation, stimulation, egg spawning, and the separation, and randomly laid about 200 ${\sim}$ 300 eggs on the bottom substrates through the night. After finishing spawning, two adults separated toward their refuges and showed 3 types of post-spawning behaviors such as the resting, occasional eggs protecting, and the egg eating. The fish was identified as a partial-parental care species after the spawning.

• Applied Microscopy
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• v.30 no.1
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• pp.21-44
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• 2000

This study was carried out to investigate sperm storage, and the fate of spermatozoa in the female reproductive tract during hibernation in Korean greater horseshoe bat, Rhinolophus ferrumequinum korai. (1) Numerous sperm occurring in uterine lumen and glands were engulfed, and disappeared by the polymorphouclear leucocytes during the hibernation. (2) The stored sperm present in caudal isthmus of oviduct only, the heads of sperm toward the oviductal epithelial cells. Therefore, the projected sperm during the mating season are only alive in the caudal isthmus of oviduct in the long hibernation. The present result suggests that the caudal isthmus of oviduct may play an important role as the principal storage site in capacitation of sperm. (3) In March, the sperm do not occur in the caudal isthmus of oviduct. It suggests that the stored sperm in the caudal isthmus of oviduct should migrate to the ampulla of the site of fertilization to meet ovum in the period of ovulation. The results of this experiment consider that prolonged sperm storage, fate of sperm and sperm migration in the long hibernation have a kind of mechanism for the fertilization.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.395-406
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• 1994

To study the conditions to enhance success of embryo transfer in the dog, 20 mixed-breed bitches were used for the experiment along with 4 male dogs for mating. The bitches were paired according to synchronism of natural estrus, or the counterpart as donor or recipient was treated with gonadotropin as FSH (follicular stimulating hormone) or PMSG (pregnant mare serum gonadotropin) for induction of estrus to be synchronized with estrus of the other bitch in natural estrus. Embryo recovery was performed in two ways for comparison, either by flushing each uterine horn after ovariohysterectomy or by flushing each horn in the state of non-ovariohysterectomy. In addition, the result of pregnancy according to the embryo stage and the repeatability of the experimental animals as donor or recipient were also investigated. FSH or PMSG was administered to the bitches which had passed over 4 months from last estrus, resulting in estrus-positive in 3 dogs of 6 FSH-treated dogs (50.0%), and in 5 dogs of 9 PMSG-treated dogs (55.6%), determined by proestrus signs and vaginal smear test. Estrus-positive bitches induced with gonadotropin were used as donor or recipient resulting in one embryo-recovered bitch as donor and one offspring-delivered bitch as recipient in 5 PMSG-treated dogs, whereas no result was obtained from 3 FSH-treated dogs. The rate of embryo recovery to be compared with number of corpus luteum was 68.2% in ovariohysterectomized dogs and 55.2% in non-ovariohysterectomized dogs, respectively. The number of dogs from which embryo was collected were 4 dogs of 6 ovariohysterectomized dogs (66.7%) and 6 dogs of 7 non-ovariohysterectomized dogs (85.7%), respectively. The result of parturition was obtained from one dog of 5 estrus-induced recipients, whereas no result was obtained from 3 natural-estrus recipients. The only dog which delivered a male puppy had been transferred 3 morulae and 2 blastocysts. Of 6 repeat-used bitches in canine embryo transfer, 3 dogs showed repeatability either as donor or recipient. These results indicated that inducing estrus of a dog with gonadotropin is feasible in canine embryo transfer to be synchronized with that of a natural-estrus dog, that embryo recovery is also possible in non-hysterectomized dogs, that the estrus-induced dog is also usable as recipient to result in parturition, and that repeat-use of a bitch as donor or(and) recipient is possible in canine embryo transfer.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.169-176
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• 2009

Domestic bitches are non-seasonally monoestrus; spontaneously ovulate only once or twice occurs at anytime of the year. Estrus induction has been applied infrequent estrus, misleading ovulation, mating difficulties, failure to conceive after normal mating, pregnancy failure and biological research. Protocol of estrus induction which included variable hormones such as FSH, GnRH, and PMSG have been applied for the last decades. Recently, Bromocriptine, one of anti-prolatin/dopamine agonist has been occasionally applied for estrus induction. The study was carried out to investigate the effective method for the induction of estrus in bitches using different hormone treatments, and the initiation time of estrus from hormone treatment by assessments of cytological observation and blood plasma progesterone concentration. A total of 54 bitches on anestrus were selected for the study and divided randomly into 8 treatment groups as follow. Control, natural estrus; FSH (L), FSH (1.5 mg/kg, twice a day, $Falltrophin^{(R)}$, Vetrepharm); FSH (H), FSH (3.0 mg/kg, twice a day); GnRH+FSH, GnRH (5 ug/kg, once first day, $GNADON^{(R)}$, Dongbang)+FSH (3 mg/kg, SID); PMSG, PMSG (50 IU/kg, every third day $FOLLIGON^{(R)}$, Intevet); GnRH+PMSG, GnRH (5 ug/kg, only first day)+PMSG (50 IU/kg, every third day); GnRH, GnRH (5 ug/kg, only first day); Bromocriptine, bromocriptine (0.3 mg/kg, SID, $Parlodel^{(R)}$, Novartis). The bitches were evaluated clinical sign, cytological exam and $OVUCHECK^{(R)}$ Premate for assessment of estrus induction. Estrus induction rates were significantly (P<0.05) higher in GnRH+PMSG (100%) compared to others. PMSG and GnRH+PMGS (87.5 and 100%) and Bromocriptine (77.8%) were higher than others except GnRH+PMSG. Analysis of vaginal smear has proved to be effective a correct assessment of estrus induction with assay of progesterone concentration by $OVUCHECK^{(R)}$ Premate. Proestrus initiated by the $6^{th}$ after induction in most case. In conclusion, bromocriptine is an effective drug for estrus induction in bitches and assay of progesterone concentration by $OVUCHECK^{(R)}$ Premate with examination of vaginal smear that should be useful to detection of estrus induction of estrus induced bitches.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.521-525
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• 2006

The present study was undertaken to evaluate the effect of flushing of ewes with concentrate pellets just before the mating season on their nutrient utilization and reproductive performance on farms. Forty-eight Malpura ewes, 1-5 years old were randomly divided into 2 groups of 24 each (G1and G2). Ewes in both the groups were grazed on natural rangeland from 07.00 to 18.00 hr followed by night shelter in animal shed. G1 ewes were maintained on sole grazing while G2 ewes, in addition to grazing, received concentrate pellets at the rate of 1.5% of their body weight. The mean biomass yield of the community rangeland was 0.46 ton DM/hectare. The intakes of DM (g/kg $W^{0.75}$), DCP (g/kg $W^{0.75}$) and ME (MJ/kg $W^{0.75}$) were higher (p<0.01) in G2 as compared to that of G1 being 86.5, 10.2 and 1.15 and 57.5, 4.7 and 0.75, respectively. The digestibility of DM, OM, CP, NDF and hemicellulose were also higher (p<0.01) in G2 as compared to that of G1 being 57.2, 76.7, 78.9, 51.9 and 81.6 and 50.8, 68.7, 68.4, 45.4 and 74.4, respectively. The conception rate was higher (79.2%) in flushed ewes as compared to that of non-flushed (66.7%). Five of the pregnant ewes died and another 5 aborted in G1 while in G2, 5 ewes aborted with no mortality. The lambing was higher (73.7%) in G2 than that in G1 (37.5%). The birth weight of lambs was higher (p<0.05) in G2 (3.47 kg) than that in G1 (2.95 kg). Further, the birth weight of male lambs was higher (3.28) than that of female lambs (3.14). It is concluded that the biomass yield of the community rangeland in semi-arid region of India is low and insufficient to meet the nutrient requirement of ewes prior to mating season. However, concentrate supplementation at the rate of 1.5% of body weight to ewes during this critical stage enhanced their plane of nutrition, reproductive performance, body condition and birth weights of lambs.

• Korean journal of applied entomology
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• v.21 no.2 s.51
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• pp.78-86
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• 1982

The ecological studies were conducted to identify some bark-beetles on apricot and plum trees in Jeonnam province. Harmful bark-beetles caught from apricot and plum trees were identified as Scolytus seulensis. Xyleborus atratus., X. germanus, X. rubricollis and X. saxeseni. The seoul barkbeetle emerged during the period from early May to late October $1980\~1981$, it happens twice in a year, with the peak July 10 and August 25 in 1950, July 15 and August 20 in 1981. A daily peak emerged for adults was at 11 AM to 1 PM. Distribution of holes on the apricot stems varied; more than 100 holes per meter in Henderson (Apricot) and Y-49057 (Apricot), 12 holes per meter in Derbyroyal (Apricot). Comparatively more holes were found in the European variety, and the cardinal distribution was in the order of east, south, west and north. The longer the longth of the mother-gallery, the greater number of egg-gallery found. Optimum temperature for mating was $27^{\circ}C$. The time for mating was longer during May-June than July-August. The fruit weight of damaged plum tree reached 12.25g around four weeks after flowering; where as that of normal tree increased up to 63.5g at harvest time. The natural enemy of the seoul bark beetle was Eurytoma sp. They were found as mature larva or pupa and they emerged from early May to the middle of June. Adult longevity was about a week.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.48-67
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• 2021

Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.

• The Korean Journal of Zoology
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• v.12 no.1
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• pp.22-28
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• 1969

In order to see if any suppressor system for the SD action was involved in natural populations of D. melanogaster samples from the populations of nine localities in Korea, Choonchun, Yusoo, Namhai, Shinchon(Seoul), Kwangjoo(Kyunggi), Koonsan, Kwangjoo(Chunnam), Jejoo and Pusan were analyzed by using the mating scheme for locating the suppressor on chromosome pairs. And also two kinds of recombinant SD lines R-1, the American line and $R(SD^NH -1)-1$, the Japanese one were used in order to see any difference of the response of the suppressor for differently originated SD. The results of the experiment are given below. (1) The suppressor system was involved in all lines of natural populations from nine localities of Korea. (2) Most of the suppressors were found to be located on the X chromosome and only a few lines from three populations showed to carry the suppressors on the second chromosome and on the third or fourth chromosoem. (3) The response of the suppressor for differently originated SD lines showed no significant difference.