• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.265-271
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• 2018

We investigated the effect of paclobutrazol (PB) and prohexadione-Ca (PC) on seed yield, and the content of oils and endogenous gibberellin in flax grown in a greenhouse. Flax seedlings were cultivated in a greenhouse with average ambient temperature ranging from $35^{\circ}C$ to $38^{\circ}C$ during the growing period, and then PB and PC were applied on the leaves. The height of flax plants was reduced significantly by the foliar application of PB and PC. The highest ripening seed rate recorded was 94.5% with 2000 ppm PC; a 10.3% increase compared with that of the control. Both PB and PC markedly increased the fructification of flax seed. The application of two plant growth retardants resulted in higher seed production in flax seedlings grown in open field than in those grown in a greenhouse. The highest oil content was observed in flax treated with PC, whereas, the lowest oil content was observed in flax treated with PB. The oil content and ratio of unsaturated fatty acids were higher in flax seedlings grown in greenhouse than in those grown in open field. The level of two endogenous bioactive gibberellins ($GA_1$ and $GA_4$) in flax seeds decreased with the application of PB and PC. The flax plants treated with PB and PC presented higher secoisolariciresinol diglucoside content than that of the control. The optimal concentration of PC was found to be 2000 ppm. In conclusion, the foliar application of 2000 ppm PC might be useful in increasing oil content and seed production in flax plants.

• Korean Journal of Veterinary Research
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• v.55 no.2
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• pp.75-80
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• 2015

Calf losses have an economic impact on larger Korean native cattle (KNC) breeding farms due to replacement, productivity, and marketing. However, little research on KNC calf mortality or causes of calf death on large-scale breeding farms has been conducted. Based on medical records and autopsy findings from the Hanwoo experimental station of the National Institute of Animal Science, calf death records from 2002 to 2011 were used to identify the causes of mortality. Mortality rate of KNC calves was 5.7%. Large differences (1.8~12.6%) in yearspecific mortalities were observed. Calf deaths were due to digestive diseases (68.7%), respiratory diseases (20.9%), accidents (6.0%), and other known diseases (2.2%). The main cause of calf death was enteritis followed by pneumonia, rumen indigestion, and intestinal obstruction. The greatest number of calf deaths occurred during the fall followed by summer. These results indicated that enteritis and pneumonia were the main reasons for calf death. However, autopsy findings demonstrated that other factors also caused calf death. This study suggested that seasonal breeding and routine vaccinations are the most important factors for preventing calf death, and improving calf health in high land areas with low temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.299-303
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• 2012

Inbreeding is the mating of relatives that produce progeny having more homozygous alleles than non-inbred animals. Inbreeding increases numbers of recessive alleles, which is often associated with decreased performance known as inbreeding depression. The magnitude of inbreeding depression depends on the level of inbreeding in the animal. Level of inbreeding is expressed by the inbreeding coefficient. One breeding goal in livestock is uniform productivity while maintaining acceptable inbreeding levels, especially keeping inbreeding less than 20%. However, in closed herds without the introduction of new genetic sources high levels of inbreeding over time are unavoidable. One method that increases selection response and minimizes inbreeding is selection of individuals by weighting estimated breeding values with average relationships among individuals. Optimum genetic contribution theory (OGC) uses relationships among individuals as weighting factors. The algorithm is as follows: i) Identify the individual having the best EBV; ii) Calculate average relationships ($\bar{r_j}$) between selected and candidates; iii) Select the individual having the best EBV adjusted for average relationships using the weighting factor k, $EBV^*=EBV_j(1-k\bar{{r}_j})$ Repeat process until the number of individuals selected equals number required. The objective of this study was to compare simulated results based on OGC selection under different conditions over 30 generations. Individuals (n = 110) were generated for the base population with pseudo random numbers of N~ (0, 3), ten were assumed male, and the remainder female. Each male was mated to ten females, and every female was assumed to have 5 progeny resulting in 500 individuals in the following generation. Results showed the OGC algorithm effectively controlled inbreeding and maintained consistent increases in selection response. Difference in breeding values between selection with OGC algorithm and by EBV only was 8%, however, rate of inbreeding was controlled by 47% after 20 generation. These results indicate that the OGC algorithm can be used effectively in long-term selection programs.

• Journal of Animal Science and Technology
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• v.55 no.2
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• pp.81-85
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• 2013

This experiment was conducted to investigate the effects of lactation records in Holstein dairy cattle on the selection rates using a total of 341,436 test records from 113, 812 heads of cattle from first to third lactation. Heritabilities for milk, fat, and protein yields were highest at first lactation (0.28, 0.24, and 0.27, respectively), and decreased to 0.14, 0.15, and 0.13 at third lactation. For the milk yields, phenotypic correlations between first and second lactation, first and third lactation, and second and third lactation were low (0.49, 0.39, and 0.47, respectively), while genetic correlations among consecutive lactations and between second and third were above 0.8 and 0.9. In Model I, of the 1,138 heads the top 1% were selected based on first lactation records, only 32.4% (396 heads) were re-selected when the second lactation records were included and the 67.6% (769 heads) were newly selected animals. While in Model II, 85.1% (1,138 heads) of the animals which were selected as the top 1% on the basis of first and second lactation records were included. A multiple trait evaluation method using multiple lactation records is more desirable than a single trait evaluation method using first lactation records only.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.665-671
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• 1993

The rate of 67 neonatal calves's infection of Theileria sergenti was investigated in random samples on the farms located in Kyeongki, Chonbuk and Jeju districts of Korea. The criteria used in verifying infection with T sergenti included the detection of parasites by giemsa's stain and acridine orange stain in the blood smear slides. Further evidence of current or previous exposure to T sergenti was based on the demonstration of T sergenti-specific antibody and antigen by the western immunoblot and the indirect immunofluorescence antibody test in the peripheral blood of the calves. The prevalence rates were 35%, 50% and 100% in Kyeongki, Chonbuk and Jeju provinces respectively and the overall prevalence in all the farms was 43.2% by means of acridine orange stain. The parasites that were observed in the peripheral blood of calves was shown surely by the western immunoblot to the characteristic 34KD antigen among the proteins of T sergenti (Korean Isolate). And the antibody of the neonatal calves reacted at the very highest titer(1 : >2,520). These data highlight the significance of T sergenti in the neonatal calf disease in Korea.

• Animal Bioscience
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• v.34 no.9
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• pp.1451-1459
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• 2021

Objective: The objectives of the study were to evaluate reproductive performance and selection response through genetic trend of community-based breeding programs (CBBPs) of Bonga sheep. Methods: Reproduction traits data were collected between 2012 and 2018 from Bonga sheep CBBPs. Phenotypic performance was analyzed using the general linear model procedures of Statistical Analysis System. Genetic parameters were estimated by univariate animal model for age at first lambing (AFL) and repeatability models for lambing interval (LI), litter size (LS), and annual reproductive rate (ARR) traits using restricted maximum likelihood method of WOMBAT. For correlations bivariate animal model was used. Best model was chosen based on likelihood ratio test. The genetic trends were estimated by the weighted regression of the average breeding value of the animals on the year of birth/lambing. Results: The overall least squares mean±standard error of AFL, LI, LS, and ARR were 375±12.5, 284±9.9, 1.45±0.010, and 2.31±0.050, respectively. Direct heritability estimates for AFL, LI, LS, and ARR were 0.07±0.190, 0.06±0.120, 0.18±0.070, and 0.25±0.203, respectively. The low heritability for both AFL and LI showed that these traits respond little to selection programs but rather highly depend on animal management options. The annual genetic gains were -0.0281 days, -0.016 days, -0.0002 lambs and 0.0003 lambs for AFL, LI, LS, and ARR, respectively. Conclusion: Implications of the result to future improvement programs were improving management of animals, conservation of prolific flocks and out scaling the CBBP to get better results.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.192-192
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• 2017

Direct-seeding cultivation of rice is increasing in Asia instead of transplanting system, because of its lower cost and operational simplicity. Low-temperature germinability (LTG) and anaerobic germinability (AG) are important characters for breeding of varieties for wide-spread adoption of direct-seeding cultivation in rice. This study was performed to characterize LTG and AG of seven rice varieties and identify varieties with strong germinability on both low-temperature and anaerobic conditions. The mean germination rate and germination vigor of seven varieties were 51.7% and 6.0 under low-temperature condition, respectively. Among these varieties, Cheongcheongjinmi and Hwanggeumnodeul had the highest germination rate of 80%, indicating that Cheongcheongjinmi and Hwanggeumnodeul have a good LTG. In anaerobic conditions, the germination rate and coleoptile length for all varieties were 47.6% and 3.2 cm, respectively. Of them, the highest germination rate and coleoptile length were observed in Subo and Hopum, respectively, suggesting that these two varieties are tolerant to anaerobic during germination stage. Molecular characterization by SDS-PAGE revealed that the protein patterns differed at 50 kDa, 40 kDa, and 22 kDa between low-temperature and anaerobic conditions. Varieties identified as good LTG or AG in this study may be used for developing new direct-seeding rice cultivars through pyramiding these traits in the breeding program.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.217-225
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• 2021

We investigated the effect of temperature and stock density on the collection efficiency of oral fluid in the pig farm in Korea. Three pig farms with similar breeding environmental conditions were selected and four pens of each farm (total 12 pens) were tested for the collection efficiency of oral fluid from pigs. Collection rate was considered as significant when oral fluid was collected from 70% of pigs within a pen. In the case of growing pigs, when internal temperature of pig barn increased by one designated degree (5℃), the oral fluid collection rate significantly decreased by 24.7% (P<0.05). The collection rate of oral fluid also decreased by 7.1% (P<0.05) as the density rate increase by one designated degree (12.5%). It was estimated that the collection efficiency of oral fluid decreased when the internal temperature of pig barn was 30℃ or higher, or barn density is higher 25% or high. On the other hand, in the case of stall-housing sows, unlike growing pigs, there was no significant differences according to the temperature, so oral fluid collection was considered to be efficient even in hot season.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.124-131
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• 2007

There is worldwide interest in buffalo as an animal for meeting the growing demands of meat, milk and work in the developing countries. One of the major constraints to full exploitation of the productive potential of buffalo has been its inherently low reproductive efficiency as reflected by late maturity, poor expression of oestrus, silent oestrus, irregular oestrous cyclicity, seasonality in breeding, anoestrus, low conception rate, long postpartum interval, repeat breeding etc. Ovarian cyclicity is regulated by endocrine and neuroendocrine mechanisms namely hypothalamic hormones, gonadotropins and ovarian steroids. Detailed endocrine investigations are suggested with special reference to the hypothalamo-hypophysial-ovarian axis to gain a better understanding of reproduction in buffalo and to modify it to derive the maximum benefit from this animal.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.517-525
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• 1993

In farms, forestry centres and greenhouses, the system can be used in growing seedlings of crops , breeding of plant and vegetables in cold areas. It may control all the activities automatically in temperature, humidity , sprinkling and heating. This is a closed-cycle control system controlled automatically by single-chip microcomputer. (MCS-51) The purpose of this system is to shorten the experimental cycle of crops , improve the survival rate of crops breeding, and ensure the growth of vegetables in the cold areas. Therefore, it can be used widely.