• Journal of Veterinary Clinics
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• v.13 no.2
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• pp.114-122
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• 1996

The aim of this study was to assess the precision of the estimates of the time of estrous cycle, optimal breeding and ovulation derived by vaginal cytology. The thirteen Korea Jin-do dogs were examined the vaginal cytology, plasma estradiol-17$$\beta $ and progesterone assay during the estrous cycle. Day 0 was the day of the first male acceptance. The main change of vaginal cytology during the estrous cycle was the high proportion of anuclear cell and erythrocyte in proestrus, superficial cell, anuclear cell and erythrocyte in estrus, parabasal cell, large intermediate cell and leukocytes in diestrus, and parabasal cell and small intermediate cell in anestrus, respectively. These data indicated that vaginal cytology was reliable method for estimating estrous cycle in Korea Jin-do dogs. In the cell indices during estrus the maximum eosinoghilic index was $92.0{\pm}$2.6 (Mean{\pm} SEM$)% at Day 2 and the maximum cornification indez was $96.0{\pm}1.3%$ at Day 2, respectively. The eosinothilic indez and cornification indez of up to 70% were found at Day -1 to Day 5 and Day -6 to Day 8, and up to 80% at Day 1 to Day 4 and Day -4 to Day 6, respectively. From these data it was presumed that eosinophilic index was more reliable index for monitoring optimal breeding time than cornification indexm because eosinophilic index peak period was shorter than cornification indeX peak period and Day 2 was the day of ovulation. Therefore, optimal breeding time was the eosinophilic index peak period, more than 80% of eosinoghilic index. The $estradiol-17{\beta}$ peak, with 3 days delayed when progesterone concentration was $4.5{\pm}0.5 ng/ml$. These data estimated that the ovulation time was the day of eosinophilic index peak, Day 2. breeding time and pvulation time in Korea Jin-do dogs.

• Journal of Veterinary Clinics
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• v.21 no.2
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• pp.115-121
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• 2004

The purpose of this study was to ascertain the breeding efficiency in Thoroughbred mare. A total of 106 mares were investigated for the status of follicle (462 cases), ovulation (179 cases) and pregnancy (346 cases). Of total examination, 46.8% was follicle measure to determine breeding time, and mating rate per cases examined was 39.9%. There was no correlation between reproductive results and size of follicles or endometrial edema or degrees of teasing alone. 143 cases were ovulated among 179 cases which were performed ovulation examination, and ovulation rate and fertilization rate per mating times were 79.9% and 39.0%, respectively. The use of hCG(human chorionic gonadotropin), to facilitate ovulation, presented to increase occurrence of double ovulations and twin fertilizations In conclusion, though more examination to estimate the optimal breeding time and higher mating rate was performed, fertilization rate per mating times was lower and then reproductive efficiency also became decreased. Therefore, it seemed that accurate examination of reproductive tracks, appropriate teasing programme and hCG administration before ovulation were of help to improve ovulation rate and fertilization rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.3
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• pp.293-297
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• 2021

Herein, two experiments were performed to determine the appropriate pH range and immersion time for organic acid-activating treatment (OAT) in a Pyropia farm. The effects of pH (0.50, 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00) on the cell mortality of Pyropia yezoensis and Ulva linza thalli were tested after 20 sec of immersion under OAT. In addition, the cell mortality of the two species was estimated under various combinations of immersion time (30, 60, and 120 sec) and pH (1.00, 1.50, and 2.00). Upon 20 sec of immersion under OAT conditions, the cell mortality of P. yezoensis did not differ at any pH but that of U. linza exceeded 90% at a pH range of 0.50-1.00. P. yezoensis showed little cell mortality upon 30 sec of immersion, but its mortality exceeded 55% upon 120 sec of immersion at a pH range of 1.00-1.50. U. linza showed 67.9-100% mortality at a pH of 1.50 and 100% mortality at a pH of 1.00, regardless of the immersion time (30-120 sec). These results indicate that for the effective removal of U. linza, the optimal pH range is 1.00-1.50 and the optimal immersion time is 20-30 sec.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.233-233
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• 2022

As the world's population grows and food needs diversify, the demand for horticultural crops for beneficial traits is increasing. In order to meet this demand, it is necessary to develop suitable cultivars and breeding methods accordingly. Breeding methods have changed over time. With the recent development of sequencing technology, the concept of genomic selection (GS) has emerged as large-scale genome information can be used. GS shows good predictive ability even for quantitative traits by using various markers, breaking away from the limitations of Marker Assisted Selection (MAS). Moreover, GS using machine learning (ML) and deep learning (DL) has been studied recently. In this study, we aim to build a system that selects phenotype-related markers using the genomic information of the pepper population and trains a genomic selection model to select individuals from the validation population. We plan to establish an optimal genome wide association analysis model by comparing and analyzing five models. Validation of molecular markers by applying linkage markers discovered through genome wide association analysis to breeding populations. Finally, we plan to establish an optimal genome selection model by comparing and analyzing 12 genome selection models. Then We will use the genome selection model of the learning group in the breeding group to verify the prediction accuracy and discover a prediction model.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.12
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• pp.1665-1671
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• 2013

Real-time quantitative PCR (qRT-PCR) is one of the important methods for investigating the changes in mRNA expression levels in cells and tissues. Selection of the proper reference genes is very important when calibrating the results of real-time quantitative PCR. Studies on the selection of reference genes in goat tissues are limited, despite the economic importance of their meat and dairy products. We used real-time quantitative PCR to detect the expression levels of eight reference gene candidates (18S, TBP, HMBS, YWHAZ, ACTB, HPRT1, GAPDH and EEF1A2) in ten tissues types sourced from Boer goats. The optimal reference gene combination was selected according to the results determined by geNorm, NormFinder and Bestkeeper software packages. The analyses showed that tissue is an important variability factor in genes expression stability. When all tissues were considered, 18S, TBP and HMBS is the optimal reference combination for calibrating quantitative PCR analysis of gene expression from goat tissues. Dividing data set by tissues, ACTB was the most stable in stomach, small intestine and ovary, 18S in heart and spleen, HMBS in uterus and lung, TBP in liver, HPRT1 in kidney and GAPDH in muscle. Overall, this study provided valuable information about the goat reference genes that can be used in order to perform a proper normalisation when relative quantification by qRT-PCR studies is undertaken.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.73-73
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• 2017

To set an optimal harvest time of main 7 whole crop silage rice cultivars, Nokyang(Ny), Mogwoo(Mw), Mogyang(My), Jungmo1029(Jm1029), Jungmo1038(Jm1038), Nokwoo(Nw) and Yeongwoo(Yw), based on feed value, we analyzed their feed values such as percent crude protein(CP), crude fat(CF), crude ash(CA), neutral detergent fiber(NDF), acid detergent fiber(ADF) and lignin. It was evaluated every 10 days from heading to 40 days after heading(DAH). Total digestible nutrient(TDN) and relative feed value(RFV) was also calculated from ADF and NDF. As results, CP was generally in decline as increasing DAH in Ny, My, Jm1029, Jm1038 and Yw and decreased to 20 DAH in Mw, decreased after increasing to 30 days in Nw. The CP content of Ny was relatively the highest ranged from 5.3% to 10.1% and Mw the lowest 4.5% to 5.2%, compared to others. CF content tend to decrease as DAH increase in Ny, My and Nw and decreased after increasing to 30 days Jm1029, increased after decreasing to 20 days Jm1038 but was not shown distinct trend of increase or decrease in Mw. Especially, that of Yw's CF gradually increased as harvest time late but relative content the lowest from 1.46% to 2.29% among 7 cultivars. The CA content of Ny, My, Jm1029 and Jm1038 approximately decreased as DAH increased and that of Mw was similar to others after heading, Nw decreased after 10 days and Yw increased after flowering. In all 7 cultivars, NDF and ADF had a tendency to decrease as days accumulated, in particular, Yw was the lowest on 30 DAH and so the content of Yw's TDN the highest(71.5%), while the lowest(67.2%) in Nw. For lignin, particularly, Mw tend to be in decline as DAH increase and was the lowest ranged from 1.34% to 1.87%. ADF analyses allows for the evaluation of in vivo digestible dry matter(DDM) and energy availability and NDF analyses provides the best indication of dry matter intake(DMI). Ultimately, the two factors can be combined to derive RFV for forage. RFV in general increased as DAH increased in all cultivars and was in order, Yw>My>Ny> Jm1038>Mw>Jm1029>Nw on 30 DAH. Taken together when these results, despite a slight increase of TDN after 30 DAH except Yw, considering forage yield potential, digestibility of grains and gradual decrease of CP and CF, the yellow ripe stage, about 30 DAH, was appropriate to harvest whole crop rice for silage use.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.304-312
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• 2023

Plant breeding is a time-consuming process, mainly due to the limited annual generational advancement. A speed breeding system, using LED light sources, has been applied to accelerate generational progression in various crops. However, detailed protocols applicable to soybeans are still insufficient. In this study, we report the optimized protocols for a speed breeding system comprising 12 soybean varieties with various maturity ecotypes. We investigated the effects of two light qualities (RGB ratio), three levels of light intensity (PPFD), and two soil conditions on the flowering time and development of soybeans. Our results showed that an increase in the red wavelength of the light spectrum led to a delay in flowering time. Furthermore, as light intensity increased, flowering time, average internode length, and plant height decreased, while the number of nodes, branches, and pods increased. When compared to agronomic soil, horticultural soil resulted in an increase of more than 50% in the number of nodes, branches, and pods. Consequently, the optimal conditions were determined as follows: a 10-hour short-day photoperiod, an equal RGB ratio (1:1:1), light intensity exceeding 1,300 PPFD, and the use of horticultural soil. Under these conditions, the average flowering time was found to be 27.3±2.48 days, with an average seed yield of 7.9±2.67. Thus, the speed breeding systems reduced the flowering time by more than 40 days, compared to the average flowering time of Korean soybean resources (approximately 70 days). By using a controlled growth chamber that is unaffected by external environmental conditions, up to 6 generations can be achieved per year. The use of LED illumination and streamlined facilities further contributes to cost savings. This study highlights the substantial potential of integrating modern crop breeding techniques, such as digital breeding and genetic editing, with generational shortening systems to accelerate crop improvement.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.16-23
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• 2017

This study aimed to determine the optimal harvesting time for covered barley to make grain silage, in Honam region of Korea. We harvested six varieties of barley every third day from 24 to 42 days after heading (DAH). The moisture content decreased from 62.4% at 24 DAH to 24% at 42 DAH. The moisture content at 36 DAH was 44.3%; however, moisture content at 39 and 42 DAH was lower than 40%. Yield of covered barley significantly increased from 24 to 42 DAH (p < 0.05). Yield at 36 DAH (557 kg/10a) was not significantly different from that at 39 and 42 DAH (p < 0.05). With respect to the feed value of barley grain silage, the amount of crude fiber and crude ash was different by harvesting time (p < 0.05). However, the amount of crude protein, crude fat, and total digestible nutrients (TDN) from 24 and 42 DAH was not significantly different. The pH of grain silage from 24 to 42 DAH was between 3.8 and 4.2 and it was stable until 36 DAH (p < 0.05). However, the pH of grain silage at 39 and 42 DAH was 5.2 and 5.8, respectively, which was higher than the pH of silage with good fermentation quality. The lactic acid content of barley grain silage from 24 to 42 DAH decreased from 5.5% to 0.5% (p < 0.05). The amount of lactic acid at 36 DAH was higher than that at 39 and 42 DAH (p < 0.05). With respect to moisture content, yield, feed value, and fermentation, the optimal harvesting time for grain silage of covered barley was 36 DAH. This could increase the use efficiency of harvesting machine for barley and reduce the harvesting time gap between whole barley silage and grain silage in Korea. Moreover, using barley grain silage for animal feed could reduce the import of corn.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.294-303
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• 2018

To set an optimal harvest time for five main whole-crop silage (WCS) rice cultivars, Nokyang (Ny), Mogwoo (Mw), Mogyang (My), Nokwoo (Nw) and Yeongwoo(Yw), based on feed value and dry matter yield, we analyzed water content (WC), feed values such as percent crude protein (CP), crude fat (CF), crude ash (CA), neutral detergent fiber (NDF), acid detergent fiber (ADF), estimated total digestible nutrients (TDN), and calculated their dry matter yield (DMY). These parameters were estimated at the booting stage and every 10 days from start of heading to 45 days after heading (DAH) to identify the optimal harvest time for these rice varieties. In all varieties, except Ny, the WC was about 65% on the $30^{th}$ DAH. In terms of WC, it is judged that there would be no major problem in preparing high quality silage when harvested between 20~30 DAH for Ny and about 30 days for the other cultivars. The CP and CA decreased significantly as the harvest time was delayed in all varieties (p<0.05). However, the CF in the tested varieties generally declined as DAH increased, and then increased again(p<0.05). The decrease in ADF and NDF was significantly different from the booting stage to 45 DAH in all varieties (p<0.05) and the estimated TDN increased gradually in all varieties as the harvest time was delayed. The TDN of all varieties, except Nw, was over 70% around 30 DAH. As harvest time was delayed, the DMY for all WCS rice increased significantly (p<0.05). The maximum DMY for each cultivar was observed at 45 DAH, however, no significant difference (p<0.05) was seen after 40 DAH for Ny and Yw, 30 DAH for Mw and Nw, and 20 DAH for My. Considering these results and others factors such as lodging, shattering, digestibility of grains, conversion of eating rice, etc., the optimal harvest time for silage use of all WCS rice tested was generally the yellow ripening stage, at about 30 DAH (30~40 DAH for Ny and Mw, and 30 DAH for My, Nw and Yw).

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.139-143
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• 2009

Most captive canids and felids at Zoos in advanced countries have been examined enough to apply artificial reproductive techniques to them. We investigated reproductive hormones and vaginal epithelial cells of a 6-year-old, female coyote, hoping these data could eventually be extended to artificial insemination with frozen-thawed conspecific semen at Seoul Zoo. As a relative of pet dogs, coyote exhibited a similar appearance with only minor differences. In vaginal smear, an increase in the number of superficial cells suggests that the bitch has reached a state close to estrus. A sudden decrease of estradiol and increase of progesterone is considered as a preovulatory event. Vaginal epithelial cells and hormones might be useful for determining the optimal time of artificial insemination in coyotes' breeding.