• Journal of Life Science
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• v.19 no.8
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• pp.1170-1176
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• 2009

Porcine reproductive and respiratory syndrome virus (PRRSV) has plagued pig populations worldwide causing severe economical impacts. In order to establish effective strategies for prevention of PRRS, infection patterns on the herd level are primarily evaluated. In the present study, therefore, serological and virological analyses were conducted in 20 pig farms suffering from PRRS. Seroprevalence levels in each farm were grouped into 3 patterns: SN (Stable sow groups/Not infected piglet groups, SI (Stable sow groups and Infected piglet groups), and UI (Unstable sow groups and Infected piglet groups). The rates of each serological pattern were 15% (n=3), 10% (n=2), and 75% (n=15), respectively. In addition, the pattern analysis was extended to virological monitoring on the same farms that further included suckling pig groups. As a result, the infection pattern was classified into 4 categories: SNI (Stable sow groups/Not infected suckler groups/Infected piglet groups), SII (Stable sow groups/Infected suckler groups/Infected piglet groups), UNI (Unstable sow groups/Not infected suckler groups/Infected piglet groups), and UII (Unstable sow groups/Infected suckler groups/Infected piglet groups). The rates of each viroprevalence were estimated at 50% (n=10), 30% (n=6), 10% (n=2), and 10% (n=2), respectively. PRRSV viroprevalence results of suckling pig groups revealed that 8 farms were considered virus positive. In 2 farms among these farms, PRRSV appeared to be transmitted vertically to suckling piglets from their sows. In contrast, piglet-to-piglet horizontal transmission of PRRSV seemed to occur in sucking herds of the remaining farms. Thus, this virological analysis on suckling piglets will provide useful information to understand PRRSV transmission routes during the suckling period and to improve a PRRS control programs. Our seroprevalence and viroprevalence data found that infection patterns between sow and piglet groups are not always coincident in the same farm. Remarkably, 15 farms belonging to the UI seroprevalence pattern showed four distinct viroprevalence patterns (SNI; 7, SII; 4, UNI; 2 and UII; 2). Among these farms, 11 farms with unstable seroprevalence sow groups were further identified as the stable viroprevalence pattern. These results indicated that despite the absence of typical seroconversion, PRRSV infection was detected in several farms, implying the limitation of serological analysis. Taken together, our data strongly suggests that both seroprevalence and viroprevalence should be determined in parallel so that a PRRS control strategies can be efficiently developed on a farm level.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.1-7
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• 2020

We can build regular customer relationships combining SNS (social networking service) with shopping mall like offline trade. A customer who once purchased is registered as reaular and the relationship continues afterward. The registered regular customer get sthe information about objective product shipment and besides it, he contacts with a story of frams, growth of vegetables, sows to harvests. Consumer can purchase with one click necessary foods as he looks at timeline. Sellers give information about news. discounts to customers. Besides it, food storages, recipes can be given to consumers. The good point here is that selling and promoting can be performed within one account. This is better than link is provided for selling an promoting separately. Like this, besides personal connections using SNS, categorization function gives consumers on line shopping mall service. Once the consumer purchase, he is registered as regular. Besides, the consumers who do not know each other, can share information, suggest products, spread the news.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.85-91
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• 2001

This study was carried out to investigate the effects of liquid boar semen on reproductive performance in swine artificial insemination. Many factors, which were breeds, time of insemination, breeding season, sperm per dose etc, have been tried to improve reproductive efficiency. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. This experiment was carried out from 1995 to 2000. There were no differences in the fertility results compared with 3 breeds (Landrace, Yorkshire and Duroc), frequencies of artificial insemination (double and triple) per estrus cycle and different seasons by using liquid boar semen. There were no significant differences in conception rate, farrowing rate and litter size using 4 trials of 3.0, 2.5, 2.0 and $1.5{\times}10^9/80ml$ in liquid boar semen with 70% of motile sperm cells. We confirmed that the sperm number per dose of $1.5{\times}10^9/80ml$ could be used for commercial artificial insemination.

• Journal of Life Science
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• v.20 no.5
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• pp.697-702
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• 2010

Ten farrow-finish farms participated in this seromonitoring that was conducted to investigate the porcine brucellosis situation in Korea. In total, eight (80.0%) of the 10 farms and 139 (24.0%) of 578 pigs tested showed a positive response in the Rose Bengal test (RBT). Seroprevalence levels were determined using RBT according to age; 35 (14.6%) of 239 piglets, 36 (31.3%) of 115 growing pigs, and 68 (30.4%) of 224 finishing pigs and sows were positive, respectively. All positive samples in RBT were tested with the tube agglutination test (TAT) and competitive ELISA (C-ELISA), simultaneously. Although 48 samples came up positive in the TAT, all samples tested with C-ELISA were negative. Among 26 rectal swab samples from the TAT positive-pigs, Yersinia enterocolitica O:9 was isolated from seven samples (26.9%). Therefore, we speculated that the positive reaction of RBT and TAT in this study might be induced by the serologically cross-reacting bacteria with Brucella abortus.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.95-104
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• 2002

This study was performed during the four seasons for the production of transgenic pigs containing the human erythropoietin(hEPO) transgene. Purebred Landrace gilts and sows approximately 8∼15 months of age (n=42) were used fur the collection of 1-cell zygotes for DNA microinjection and transfer. Retrospectively, estrus synchronization and superovulation schemes were evaluated to assess practicality for zygote collection. Synchronization and superovulation procedures were used that cyclic gilts were synchronized with 20mg altrenogest (ALT) per day for 9days after PG600 administration followed by superovulation with 1500IU pregnant mares serum gonadotropin (PMSG) and 500IU human chorionic gonadotrophin (hCG). Preparation of recombinant gene for microinjection is mice whey acidic protein promoter (mWAP) linked to human erythropoietin (hEPO) gene. After hormone treatment, 650 embryos were collected from 23 donors and 83.1% (540/650) embryos were in 1-cell stage which can be visualized the pronuclei for DNA microinjection. A total of 543 DNA microinjected embryos fiom donors were transferred to 19 synchronized recipients, seven of them maintained pregnancy and delivered 47 piglets. One of the 47 offsprings were determined to have transgene by PCR analysis. The overall rate of transgenic production was 2.13% (tansgenic/offspring). This study provides the success and useful information regarding production of transgenic pig for bioreactor research.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.87-94
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• 2002

This study was performed during the four seasons for the production of transgenic pigs containing the Cellulase Digest Gene. Purebred Landrace gilts and sows approximately 8∼15 months of age (n=126) were used for the collection of 1-cell zygotes for DNA microinjection and transfer. Retrospectively, estrus synchronization and superovulation schemes were evaluated to assess practicality fur zygote collection. Synchronization and superovulation procedures were used that cyclic gilts were synchronized with 20mg altrenogest (ALT) per day for 9 days after PG600 administration followed by superovulation with 1000 IU pregnant mares serum gonadotropin (PMSG) and 750IU human chorionic gonadotrophin (hCG). The cellulase digestion gene for microinjection is rat elasterase promoter (rEl) linked to CelD gene. After hormone treatment, 1,422 embryos were collected from 91 donors and 95.6% (1,359/1,422) embryos were in 1-cell stage which can be visualized the pronuclei for DNA microinjection. A total of 725 DNA microinjected embryos transferred into 35 recipients and produced 65 piglets from 13 litters. Pregnancy rate according to the number of transferred embryos to recipients was higher the group which received 21 to 24 embryos (50.0%) than other groups 20.0% in less and 33.3% in more. A tail tissue was collected from 65 piglets for biopsy. PCR screening was performed on each DNA sample using two separate sets of primers specific for the 5'- and 3'-flanking region of the rEl-CelD gene. Five of the 65 piglets (7.69%) were positive for the transgene. This study provide useful information regarding production of transgenic pig for bioreactor research.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.119-124
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• 2002

This study was carried out to investigate the effects of packing materials of frozen boar semen to improve reproductive performance efficiency in pig. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. We compared packing protocols for frozen boar semen among 5$m\ell$ maxi-straw, 5$m\ell$ cryogenic-vial, and aluminum-pack. Cryogenic-vial packing material showed similar sperm characteristics compared with maxi-straw packing material when the sperm was frozen above 15cm from liquid nitrogen and thawed at 52$^{\circ}C$ for 190 seconds. We investigated different thawing times to find out the optimal condition of freezing and thawing protocol with cryogenic-vial. Freezing above 15cm from liquid nitrogen and thawing at 52$^{\circ}C$ for 190 seconds were the optimal protocol compared with 120 and 150 seconds. However, normal acrosome rates did not show any differences among thawing times. Post-thawing results of maxi-straw in water at 52$^{\circ}C$ for 45 seconds had better total motility and curve linear velocity than those of cryogenic-vial in water 52$^{\circ}C$ for 190 seconds. However, there were no differences on straightness and normal apical ridge of sperm between maxi-straw and cryogenic vial. Non-return rate, farrowing rate and litter size of sows inseminated with frozen boar semen of commercial farms were higher in the maxi-straw than cryogenic-vial, but there were no significant differences between maxi-straw and cryogenic-vial. In conclusion, there were no significant differences between maxi-straw and cryogenic-vial and so, we may replace cryogenic-vial packing method instead of maxi-straw packing method by improvement of freezing and thawing rate.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.9
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• pp.1475-1481
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• 2019

Objective: The objective of the present study was to investigate pork quality from Hereford${\times}$Berkshire female and intact male pigs reared outdoors in an alternative production system. Methods: Berkshire purebred sows were artificially inseminated, once in the fall and again in the spring of the following year, with semen from Hereford boars and managed free of antibiotics in an outdoor hoop structure until the last month of pregnancy, after which they were moved to a pasture-based unit of 0.8 hectares with individual lots with a farrowing hut, shade, and water ad libitum. Piglets were weaned at 4 weeks of age and housed in a deep-bedded hoop structure, grouped by sex. Animals were harvested at market weight of 125 kg, approximately 200 days of age. Hot carcass weight was collected at the time of the harvest. After 24 hours of refrigeration, carcass characteristics were measured. Longissimus dorsi samples collected from the right side loin. Loins were cut into 2.54-cm thick chops and were used to measure marbling score, color score, drip loss, and ultimate pH. Sensory panel tests were conducted as well at North Carolina State University. For pork characteristics and sensory panel data, trial and sex were included in the statistical model as fixed effects. Hot carcass weight was included in the model as a covariate for backfat thickness. Results: Neither the subjective nor the objective color scores displayed any differences between the boars and the gilts. No difference was found for pH and marbling score between trials or sexes. Gilts had a thicker backfat measurement at the last lumbar and a narrower longissimus muscle area measurement when compared to the boars. The only difference in the sensory characteristics was found between the trials for texture and moisture scores. Conclusion: Consumers were not able to detect boar taint under the condition of this study, which is that the intact males were reared outdoors. Additional trials would be necessary; however, based on the results of the present study, outdoor rearing can be suggested as a solution to the issue of boar taint.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.514-520
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• 2019

The reduction in performance due to inbreeding (i.e. inbreeding depression) has long been documented in plant and animal populations. The population of Korean native pigs are small and this breed is valuable in Korea.. This study was aimed to investigate effects of inbreeding depression on total number of piglets born (TNB) and number of piglets born alive (NBA) in Korean native pigs. We used 2,806 pedigree and 303 sows's data with 483 phenotypic records. After estimating genetic parameters for each traits, inbreeding depression was estimated using a mixed model in which the inbreeding coefficient was included as a covariate. Korean native pigs had high heritability for each traits. Inbreeding coefficient constantly increased from 1998 to 2017~2018 but there is no reduction for each traits in 2017~2018 in compared with those in 1998. Significant inbreeding depression was detected for TNB (p=0.03) but not for NBA (p=0.41). In addition there are significantly positive interactions between inbreeding coefficient and breeding value for both traits (p<0.05). These results suggest that Korean native pigs are still having genetic variation for TNB and NBA, which could overcome reproductive risks from inbreeding coefficient increase.

• Journal of Veterinary Science
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• v.21 no.3
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• pp.36.1-36.9
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• 2020

Background: Pseudorabies, also known as Aujeszky's disease, is caused by the pseudorabies virus (PRV) and has been recognized as a critical disease affecting the pig industry and a wide range of animals around the world, resulting in great economic losses each year. Shandong province, one of the most vital food animal-breeding regions in China, has a very dense pig population, within which pseudorabies infections were detected in recent years. The data, however, on PRV epidemiology and coinfection rates of PRV with other major swine diseases is sparse. Objectives: This study aimed to investigate the PRV epidemiology in Shandong and analyze the current control measures. Methods: In this study, a total number of 16,457 serum samples and 1,638 tissue samples, which were collected from 362 intensive pig farms (≥ 300 sows/farm) covered all cities in Shandong, were tested by performing enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Results: Overall, 52.7% and 91.5% of the serum samples were positive for PRV-gE and -gB, respectively, based on ELISA results. In addition, 15.7% of the tissue samples were PCR positive for PRV. The coinfection rates of PRV with porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus, and classical swine fever virus were measured; coinfection with PCV2 was 35.0%, higher than those of the other two viruses. Macroscopic and microscopic lesions were observed in various tissues during histopathological examination. Conclusions: The results demonstrate the PRV prevalence and its coinfection rates in Shandong province and indicate that pseudorabies is endemic in pig farms in this region. This study provides epidemiological data that can be useful in the prevention and control of pseudorabies in Shandong, China.