• Animal Bioscience
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• v.34 no.12
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• pp.1879-1885
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• 2021

Objective: Owing to the lack of a breeding index for efficient and quick fertility evaluations of Holstein bulls when using traditional or genome-wide detection methods, this study aimed to determine whether in vitro fertilization (IVF) could be used as an indicator of conception rate of artificial insemination (AI). Methods: Conventional and sexed frozen semen from nine bulls were used for IVF and AI. Results: The IVF and AI conception rates of each bull were confirmed to be positively correlated between the conventional frozen and sexed frozen semen. The correlation coefficient R values of nine bulls between IVF and AI methods were 0.73 and 0.97 for the conventional frozen and sexed frozen semen, respectively. The average conception rate of three bulls undergoing AI was 69.5% and 64.2%, 61.8% and 58.8%, and 48.2% and 46.2% in first-, second-, and third-born cows when conventional frozen and sexed frozen semen were used, respectively, which showed a positive correlation with the fertilization rate in the same parity. We propose an evaluation standard to assess the fertilization ability of bulls based on their IVF test results, which is categorized into three grades: grade one, normal fertility bull with an AI conception rate of 40%±5% and IVF rate of 45% to 60%; grade two, higher fertility bull with an AI conception rate of 50%±5% and IVF rate of 61% to 80%; and grade three, highest fertility bull with an AI conception rate of 60%±5% and IVF rate of >80%. Conclusion: These findings reveal that IVF results can be used as a breeding index for bulls to evaluate their AI conception ability, which may shorten the time required to select bulls for breeding.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.912-921
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• 2023

Genetic diversity analysis is crucial for maintaining and managing genetic resources. Several studies have examined the genetic diversity of Korean domestic chicken (KDC) populations using microsatellite markers, but it is difficult to capture the characteristics of the whole genome in this manner. Hence, this study analyzed the genetic diversity of several KDC populations using high-density single nucleotide polymorphism (SNP) genotype data. We examined 935 birds from 21 KDC populations, including indigenous and adapted Korean native chicken (KNC), Hyunin and Jeju KDC, and Hanhyup commercial KDC populations. A total of 212,420 SNPs of 21 KDC populations were used for calculating genetic distances and fixation index, and for ADMIXTURE analysis. As a result of the analysis, the indigenous KNC groups were genetically closer and more fixed than the other groups. Furthermore, Hyunin and Jeju KDC were similar to the indigenous KNC. In comparison, adapted KNC and Hanhyup KDC populations derived from the same original species were genetically close to each other, but had different genetic structures from the others. In conclusion, this study suggests that continuous evaluation and management are required to prevent a loss of genetic diversity in each group. Basic genetic information is provided that can be used to improve breeds quickly by utilizing the various characteristics of native chickens.

• Korean Journal of Veterinary Research
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• v.15 no.1
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• pp.101-108
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• 1975

The susceptibility of 536 isolates of Staphylococcus and 313 isolates of Streptococcus to a number of chemotherapeutics were studied. These organisms were isolated from bovine mastitis during 1973 and 1974. In addition to this, the rate of multiple resistance of 425 isolates of Staphylococcus and 164 isolates of Streptococcus, isolated in 1974, to the chemotherapeutics was analysed. The results obtained in this work were summerized as follows: 1. Staphylococcus and Streptococcus isolated in 1974 showed a higher resistance, with 3 exceptions of chemotherapeutics, than the isolates of 1973. 2. Staphylococcus isolated in 1973 and 1974 showed a higher susceptibility than Streptococcus. 3. The strains of Staphylococcus resistant to colistin were 39 strains (9.2%), to colistin and sulfisoxazole 33 (7.8%), to streptomycin, kanamycin, colistin and sulfisoxazole 20 (4.7%), and to penicillin, colistin and sulfisoxazole 18 (4.2%). 4. The strains of Streptococcus resistant to colistin were 17 strains (10.4%), to streptomycin, kanamycin, colistin and sulfisoxazole 13 (7.9%), to colistin and sulfisoxazole 11 (6.7%) and to penicillin, colistin and sulfisoxazole 11 (6.7%).

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.215-219
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• 2010

The objective of this study was to examine the reproductive characteristics of cloned miniature piglets produced from surrogate domestic pigs. Somatic cell nuclear transfer (SCNT) miniature pig embryos were transferred into domestic pigs. As controls, domestic pigs of the same breed with surrogates for SCNT embryos and miniature pigs of the same breed with the somatic cell donor were bred by artificial insemination and natural mating, respectively. Surrogate domestic pigs that farrowed cloned miniature piglets had a significantly longer gestation length (118.1 days) than conventionally bred domestic (115.4 days) and miniature (115.5 days) pigs. Furthermore, the birth weight of cloned miniature piglets produced from domestic pigs (743 g) was significantly greater than that of miniature piglets produced by natural breeding (623 g). Also, cloned miniature piglets had a significantly lower weaning rate (49.7%) than conventionally produced domestic (91.5%) and miniature (100%) piglets. No differences were observed between female and male cloned piglets in gestation length, litter size, birth weight, or weaning rate. Our results demonstrate that gestation length is extended in domestic pigs that are transferred with SCNT miniature pig embryos and that cloned miniature piglets have increased birth weight and high pre-weaning mortality.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2003.06a
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• pp.184-184
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• 2003

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.17-25
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• 2022

This study was carried out the estimation on consumption patterns and consciousness of domestic forage for improvement of the quality of domestic forage. Although the cultivated area in South Korea of forage has increased significantly compared to the past, the self-sufficiency rate of domestic forage has increased to around 80% since 2010. Also, livestock farmers prefer to use import forage than domestic due to convenience of use. In Korean beef farms, the ratio of import to domestic forage was higher in domestic forage (import forage 3 : domestic forage 7). In the method of securing domestic forage, purchase of forage (55.6%) was higher than self-cultivation of forage (44.4%). The ratio of use by bailing type was shown in the order of rice staw rice straw (50.5%), domestic hay (15%), imported hay (12.5%), and total mixed ratio (10.7%). The preference of forage was in the order of amount of foreign matter, moisture content, price, feed value in Korean native cattle farm. The result of satisfaction with domestic and import forage showed that the satisfaction of domestic forage price was higher than import forage, while the moisture content and foreign matter of forage were lower than import forage. In addition, in the results of the satisfaction and importance of domestic roughage compared to imported roughage, satisfaction with imported roughage was generally high in all items except for price. As a result, in order to improve the satisfaction of domestic forage in Korean native cattle farm, it is necessary to minimize foreign matter in forage and increase hay production for moisture content uniform in forage.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.285-288
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• 2012

Salmonella I 4,[5],12:i:- was a monophasic variant of Salmonella (S.) Typhimurium and notorious for re-emerging candidate which would replace S. Typhimurium DT104 for antibiotic resistance. Recently, isolation rate was increased on human and industrial animals but there was no case in domestic animals but human in Korea. This was first isolation case from domestic animals in Korea. The five isolates from feces of duck (n = 3), chicken (n = 1), and wild bird (n = 1) showed antibiotic resistance against cephems and aminoglycosides. These means that the spread of emerging bacterial pathogens to domestic animals and the need of systemic management for Salmonella I 4,[5],12:i:-.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.1
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• pp.92-102
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• 2019

Objective: To investigate changes in rumen fermentation characteristics and bacterial community by a sudden change to a high concentrate diet (HC) in Korean domestic ruminants. Methods: Major Korean domestic ruminants (each of four Hanwoo cows; $545.5{\pm}33.6kg$, Holstein cows; $516.3{\pm}42.7kg$, and Korean native goats; $19.1{\pm}1.4kg$) were used in this experiment. They were housed individually and were fed ad libitum with a same TMR (800 g/kg timothy hay and 200 g/kg concentrate mix) twice daily. After two-week feeding, only the concentrate mix was offered for one week in order to induce rapid rumen acidosis. The rumen fluid was collected from each animals twice (on week 2 and week 3) at 2 h after morning feeding using an oral stomach tube. Each collected rumen fluid was analyzed for pH, volatile fatty acid (VFA), and $NH_3-N$. In addition, differences in microbial community among ruminant species and between normal and an acidosis condition were assessed using two culture-independent 16S polymerase chain reaction (PCR)-based techniques (terminal restriction fragment length polymorphism and quantitative real-time PCR). Results: The HC decreased ruminal pH and altered relative concentrations of ruminal VFA (p<0.01). Total VFA concentration increased in Holstein cows only (p<0.01). Terminal restriction fragment length polymorphism and real-time quantitative PCR analysis using culture-independent 16S PCR-based techniques, revealed rumen bacterial diversity differed by species but not by HC (p<0.01); bacterial diversity was higher in Korean native goats than that in Holstein cows. HC changed the relative populations of rumen bacterial species. Specifically, the abundance of Fibrobacter succinogenes was decreased while Lactobacillus spp. and Megasphaera elsdenii were increased (p<0.01). Conclusion: The HC altered the relative populations, but not diversity, of the ruminal bacterial community, which differed by ruminant species.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.115-122
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• 2019

The companion animal related businesses are rapidly growing as the pet population increases in Korea. In this study, we analyzed the market trends of companion animal food and products to offer basic information that can be used in related policies and industries. The data were collected using Nielsen Korea's wholesale/retail distribution channels. As a result, in the case of companion dog food, PB products of domestic companies showed the highest market share with 24.6%, and the ratio of domestic companies(54.8%) was higher than that of import companies(45.2%). Domestic PB products also had the highest market share(16.5%) in companion cat food, however, the ratio of import companies(71.6%) was higher than that of domestic companies(28.4%). In the case of the market share of the companion animal products(toys, oral and bath supplies), Nosework mats from domestic companies were top ranked in the toy category(28.0%). Oral products(62.5%) and bath products(59.5%) from domestic companies were also having a higher market share than import companies. Our research may help domestic companion animal product companies to steadily increase market share and the amount of their export.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1688-1695
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• 2016

The maternally inherited mitochondrial DNA (mtDNA) D-loop region is widely used for exploring genetic relationships and for investigating the origin of various animal species. Currently, domestic ducks play an important role in animal protein supply. In this study, partial mtDNA D-loop sequences were obtained from 145 samples belonging to six South-East Asian duck populations and commercial duck population. All these populations were closely related to the mallard duck (Anas platyrhynchos), as indicated by their mean overall genetic distance. Sixteen nucleotide substitutions were identified in sequence analyses allowing the distinction of 28 haplotypes. Around 42.76% of the duck sequences were classified as Hap_02, which completely matched with Anas platyrhynchos duck species. The neighbor-joining phylogenetic tree also revealed that South-East Asian duck populations were closely related to Anas platyrhynchos. Network profiles were also traced using the 28 haplotypes. Overall, results showed that those duck populations D-loop haplotypes were shared between several duck breeds from Korea and Bangladesh sub continental regions. Therefore, these results confirmed that South-East Asian domestic duck populations have been domesticated from Anas platyrhynchos duck as the maternal origins.