• Journal of Korean Society on Water Environment
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• v.35 no.3
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• pp.224-233
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• 2019

Nitrogen components in liquid manure can reduce safety and quality of environment harmfully. To minimize the environmental risks of manure, understanding fate of manure in environment is necessary. This study aimed at investigating applicability of a simplified Level III fugacity model for simulating $NH_3-N$ component to analyze environmental fate and transport of $NH_3-N$ in liquid manure and to provide basis for improving management of N in the liquid manure system and for minimizing the environmental impacts of N. The model simulation conducted for four environmental compartments (air, water, soil, and rice plants) during rice-cropping to trace $NH_3-N$ component and provided applicability of the Level III fugacity model in studying the environmental fate of $NH_3-N$ in manure. Most of $NH_3-N$ was found in water body and in rice plants depending upon the physicochemical properties and proper removal processes. For more precise model results, the model is needed to modify with the detailed removal processes in each compartment and to collect proper and accurate information for input parameters. Further study should be about simulations of various N-typed fertilizers to compare with the liquid manure based on a modified and relatively simplified Level III fugacity model.

• Journal of agriculture & life science
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• v.53 no.5
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• pp.153-165
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• 2019

This paper analyzes the priorities of introducing agricultural environmental conservation practices for the successful introduction of agricultural environmental conservation programs and promotes customized agricultural environment conservation practices packages suitable for the local environment. Agricultural environmental conservation practice consists of three fields: soil, water, and air, nine sub-fields, and 30 practice skills. Using the advantages of AHP and BWS appropriately for priority analysis, three areas and nine sub-fields are measured using AHP techniques, and the practical activities of each fields are measured by priorities using BWS techniques to enhance the differentiation and completeness of research. In addition, the criteria for evaluating priorities of practical activities used 'Environmental effectiveness' and 'Technical feasibility'. As a result of the priority evaluation, the 'Soil testing and reduction of fertilizer and livestock manure application' activities were evaluated as having the highest priority. Based on the results of the priorities for these practical activities, examples of customized practical activity packages by farming type and environmental conditions were presented.

• Korean Journal of Veterinary Service
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• v.44 no.2
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• pp.85-91
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• 2021

This study was performed to identify the prevalence of cryptosporidiosis and giardiasis in diarrhea feces of Korean native calves raised in Gimje, Jeollabuk-do, with a rapid diagnostic kit. The prevalence of both diseases were classified according to the age of calf, season of sampling period, and sampled farm where diarrheic calf is commonly observed. In diarrhea feces of 431 calves, cryptosporidiosis had a high incidence rate between 1 and 3 weeks of age, whereas giardiasis showed a high incidence between 4 and 6 weeks of age. It is thought that the incidence of protozoan diseases is markedly influenced by the calf's postnatal age. Regarding with the sampling season, the prevalence of cryptosporidiosis and giardiasis in calves was significantly higher in spring and summer than in autumn and winter (P<0.05). Among the sampled farms where both diseases are commonly observed, cryptosporidiosis was more frequently detected than giardiasis in calves. Particularly, in farms where cryptosporidiosis is common, it tends to be a disease that is difficult to eradicate as it occurs continuously throughout the year. Hygiene management such as regular cleaning and disinfection of the livestock and the surrounding environments is considered necessary to reduce and prevent damage from these protozoal diseases.

• Animal Bioscience
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• v.35 no.4
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• pp.544-555
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• 2022

Objective: Spermatozoa are produced within the seminiferous tubules after sexual maturity. The expression levels of mRNAs and lncRNAs in testicular tissues are different at each stage of testicular development and are closely related to formation of the extracellular matrix (ECM) and spermatogenesis. Therefore, we set out to study the expression of lncRNAs and mRNAs during the different developmental stages of the goat testis. Methods: We constructed 12 RNA libraries using testicular tissues from goats aged 3, 6, and 12 months, and studied the functions of mRNAs and lncRNAs using the gene ontogeny (GO) and Kyoto encyclopedia of genes and genomes (KEGG) databases. Relationships between differentially expressed genes (DEGs) were analyzed by lncRNA-mRNA co-expression network and protein-protein interaction network (PPI). Finally, the protein expression levels of matrix metalloproteinase 2 (MMP2), insulin-like growth factor 2 (IGF2), and insulin-like growth factor-binding protein 6 (IGFBP6) were detected by western blotting. Results: We found 23, 8, and 135 differentially expressed lncRNAs and 161, 12, and 665 differentially expressed mRNAs that were identified between 3 vs 6, 6 vs 12, and 3 vs 12 months, respectively. GO, KEGG, and PPI analyses showed that the differential genes were mainly related to the ECM. Moreover, MMP2 was a hub gene and co-expressed with the lncRNA TCONS-0002139 and TCONS-00093342. The results of quantitative reverse-transcription polymerase chain reaction verification were consistent with those of RNA-seq sequencing. The expression trends of MMP2, IGF2, and IGFBP6 protein were the same as that of mRNA, which all decreased with age. IGF2 and MMP2 were significantly different in the 3 vs 6-month-old group (p<0.05). Conclusion: These results improve our understanding of the molecular mechanisms involved in sexual maturation of the goat testis.

• Journal of Korea Water Resources Association
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• v.55 no.5
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• pp.371-381
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• 2022

Since tributaries have greater water quality variability than main streams, a comprehensive evaluation method that considers the effects of various parameters rather than one water quality parameter has been introduced for effective water quality management of tributaries, but the characteristic of the watershed is not considered. In this study, the urbanization rate, livestock excreta generation, and industrial wastewater discharge in the Hantan River middle-watershed classify urban and non-urban watersheds, and evaluate the suitability of water quality indexes by watershed characteristics by analyzing water quality characteristics and calculating CCME WQI, RTWQI, and NSFWQI. Factor analysis was used to understand the effect of water quality parameters used to calculate the water quality index on the water quality index results. As a result of the factor analysis, the relationship between CCME WQI, TC, and FC was derived, and the relationship between RTWQI and DO, SS in urban watersheds and NSFWQI and FC in non-urban watersheds was revealed. As a result of evaluating suitability through comparison with BOD and T-P grades, it was interpreted that the suitability of the water quality index was low in urban watersheds and that comprehensive water quality evaluation using RTWQI was possible in non-urban watersheds.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.15-22
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• 2023

This study was to investigate the relationship between chick weight in the growing period and the laying performance of Korean native chicken (KNC) breeders. We measured the body weights of 1,384 KNC breeders at 1-140 days of age at two-week intervals. The age at first egg laying, hen-day and hen-housed egg production, and the egg weights were investigated. Correlation coefficients between the body weight and egg production traits were analyzed. The results showed that the correlation coefficients between body weight and age at first egg laying were significantly positive before 4 weeks, but negative after 8 weeks of age. The correlation coefficients between body weight and egg production rate were estimated to be negative before 8 weeks and positive after 12 weeks of age. Coefficients of hen-day and hen-housed egg production were similar. There was little correlation between body weight and egg weight at 32 weeks of age, whereas a low positive correlation was with egg weight at 50 weeks. In conclusion, there was little correlation between body weight and laying performance before 8 weeks of age, whereas a significant positive correlation was with body weight after 12 weeks. The results suggest that as the chick's weight increases in the late growing stage, sexual maturity is faster, the egg production rate is higher, and the egg weight increases. Therefore, the weight management of KNC female breeders is very important in the late growing stage, and the body weight of chicks must be maintained above the standard weight.

• Journal of Animal Science and Technology
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• v.54 no.2
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• pp.141-147
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• 2012

The present survey was conducted to provide basic information on Hanwoo calf management. Eight hundred and sixty-two Hanwoo breeding farms from all nine provinces were surveyed via personal interviews. The percentages of farms categorized by herd size were 30.5%, 32.8%, 26.0% and 10.7% for <50 heads, 51-100 heads, 101-200 heads, and >200 heads, respectively. More than 50% of farms offered calf starter at 6-10 days of age, showing that calf starter was offered relatively at an earlier age. Calf starter was replaced every three days by 30.1% of farms. The percentages of farms replacing starter weekly (19.2%) were even higher than those of replacing starter daily (18.8%), suggesting that the frequency of replacing starter needs to be increased to maintain starter freshness and to increase starter intake. About one-third of farms offered forage at 6-10 days of age and 21% of farms offered even at 1-5 days of age although it has been well known that forage does not contain either nutrient density or nutrient profile necessary to stimulate rumen papillae development, especially before weaning. Furthermore, about half of farms used rice straw with calf starter. Water was offered relatively at an earlier age (1-5 days of age) by 55% of farms. Deciding when to wean calves should be based on starter intake rather than age but less than 50% of farms decided weaning age by starter intake. In conclusions, to reduce weaning age of Hanwoo calves by rapid rumen papillae development it is necessary to provide fresh starter and water by increasing frequency of starter replacing and water trough cleaning and not to feed forage before weaning.

• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.253-263
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• 2011

This study was conducted to gain preliminary data for restoration and management of constructed small-scale ponds in paddy fields through analysis of their physicochemical and biological properties. A field survey was performed at 13 small-scale ponds located in paddy fields from August 2009 to October 2010. Structural properties, water quality, soil characteristics and fish fauna were measured. Results showed that small-scale ponds without frames might lose their function over time because of crumbling walls. Therefore, it is necessary for these ponds to have frames for soil protection and sustainable maintenance. Chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) concentration were higher than the water quality standard for agricultural water in small-scale ponds. In particular, TN concentration was 8.03 mg $L^{-1}$ and over 8 times the water quality standard because of the presence of livestock such as cows and pigs in the study areas. Sand, organic matter and available phosphorus contents of soil in small-scale ponds was 53.4${\pm}$16.6%, 21.8${\pm}$9.74 g $kg^{-1}$ and 12.8${\pm}$7.59 mg $kg^{-1}$, respectively indicating that sand and available phosphorus contents were suitable for plants in small-scale ponds, but organic matter contents was somewhat low in newly constructed small-scale ponds, and would take some time to stabilize for plant growing. Fish fauna was not diverse with only 4 species at all sites surveyed. Collected fishes share a common feature that they all inhabit paddy fields or canals with shallow water depth. In this study, all ponds were not linked to the streams and canals around them. It appears that connection to adjacent streams was the major factor controlling fish fauna in small-scale ponds. The results of statistical analysis were classified into three groups. Factor 1 was 26.3%, which shows a structural properties such as area and depth of small-scale pond. As for factor 2, it appears on 20.1%, showing water quality like a TP, suspended solids (SS) and COD. Small-scale ponds were classified into three groups by factor scores. Group I consisted of 6 small-scale ponds, which were larger than the others. Group III had higher water quality than the others. We conclude that the most important points to be considered for restoration and management of small-scale ponds is connection with adjacent streams or ditches and depth and size of the small-scale pond.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.1
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• pp.45-52
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• 2019

This experiment was carried out to study the change of productivity and feed value in different types of hilly pasture. The pasture utilized in the experiment was placed on the experimental farm of Pyeongchang Campus of Seoul National University. Forage production type(FP; Orchardgrass 18 + Tall Fescue 12 + Timothy 5 + White clover 5 kg/ha) and Public farm type(PF: Orchardgrass 12 + Tall Fescue 18 + Timothy 5 + White clover 5 kg/ha) pasture were established in September 3, 2014 and utilized (cutting or grazing) four times every year. Growth characteristics, yield and forage quality were investigated for two years. Plant height of grasses was the highest in the $1^{st}$ cutting and legumes was in the $2^{nd}$ cutting. Dry matter (DM) content was highest at every the $1^{st}$ cut grasses significantly lower at the $2^{nd}$ harvest (p<0.05). However, there was no significant difference in the $2^{nd}$, $3^{rd}$ and $4^{th}$ harvest in 2016. In the botanical composition change, the portion of legume was gradually increased after pasture establishment and the ratio of weed and bare land was higher at $2^{nd}$ and $3^{rd}$ cutting, but it was decreased at $4^{th}$ harvest. There was no significant difference in 2016 of fresh yield between two farm types (p>0.05). The yield of dry matter showed similar trend of fresh yield and forage production type was higher than that of public farm type (p<0.05). The forage intake by livestock was 1,452 kg/ha in 2015 and 1,743 kg/ha in 2016. Pasture utilization ratio of public farm type pasture was highest in the $3^{rd}$ grazing time. Forage quality of pasture in relation to management type had not significant difference, but there was difference in harvest times. Crude protein (CP) was the lowest in the $1^{st}$ harvest and total digestible nutrient (TDN) was highest in the $1^{st}$ harvest and lowest in the $4^{th}$ harvest. Based on the above results, it is found that the establishment of pasture suitable for farm's situation is important for set up of Korean model of hilly pasture. Although the forage production type is superior on forage productivity, it is recommended that the results will be provided as basic data for management of public farm type in the future.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.65-75
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• 2019

A number of Korean native chicken(KNC) populations were registered in FAO (Food and Agriculture Organization) DAD-IS (Domestic Animal Diversity Information Systems, http://www.fao.org/dad-is). But there is a lack of scientific basis to prove that they are unique population of Korea. For this reason, this study was conducted to prove KNC's uniqueness using 25 Microsatellite markers. A total of 548 chickens from 11 KNC populations (KNG, KNB, KNR, KNW, KNY, KNO, HIC, HYD, HBC, JJC, LTC) and 7 introduced populations (ARA: Araucana, RRC and RRD: Rhode Island Red C and D, LGF and LGK: White Leghorn F and K, COS and COH: Cornish brown and Cornish black) were used. Allele size per locus was decided using GeneMapper Software (v 5.0). A total of 195 alleles were observed and the range was 3 to 14 per locus. The MNA, $H_{\exp}$, $H_{obs}$, PIC value within population were the highest in KNY (4.60, 0.627, 0.648, 0.563 respectively) and the lowest in HYD (1.84, 0.297, 0.286, 0.236 respectively). The results of genetic uniformity analysis suggested 15 cluster (${\Delta}K=66.22$). Excluding JJC, the others were grouped in certain cluster with high genetic uniformity. JJC was not grouped in certain cluster but grouped in cluster 2 (44.3%), cluster 3 (17.7%) and cluster8 (19.1%). As a results of this study, we can secure a scientific basis about KNC's uniqueness and these results can be use to basic data for the genetic evaluation and management of KNC breeds.