• Korean Journal of Veterinary Research
• /
• v.48 no.1
• /
• pp.67-73
• /
• 2008

Porcine reproductive and respiratory syndrome (PRRS) is the most economically important viral infectious disease in pig populations worldwide. This study was conducted to better understand the epidemic and dynamics of PRRS virus (PRRSV) on each farm and to evaluate the risk of PRRSV infection in Korea. Interviews with pig farmers were carried out to obtain PRRS vaccination programmes in 60 pig farms throughout Korea. Blood samples were also collected from the 59 pig farms to investigate outbreak patterns of each farm. Vaccination against PRRS was performed in 16.7% farms for breeding pigs and 8.3% of farms for nursery pigs. According to the seroepidemiological analysis, 56 (94.9%) out of 59 farms were considered to be affected by PRRSV infection. The results revealed that 68.9% of sows tested were seroconverted and interestingly, gilt herds had the highest seropositive rate (73%), suggesting that gilts may play a key role in PRRSV transmission in sow herds. Among the PRRS-affected piglet herds, 33 (55.9%), 14 (23.7%) and 6 (10.2%) farms were initially infected with PRRSV during the weaning, suckling and nursery period, respectively. It seems likely, therefore, that PRRSV infection predominantly occurs around the weaning period in piglet herds. Based on antibody seroprevalence levels in both sow and piglet groups, we were able to classify patterns of PRRSV infection per farm unit into 4 categories; category 1 (stable sow groups and non-infected piglet groups), category 2 (unstable sow groups and non-infected piglet groups), category 3 (stable sow groups and infected piglet groups), and category 4 (unstable sow groups and infected piglet groups). Our data suggested that 43 (72.9%) farms were analysed to belong to category 4, which is considered to be at high-risk for PRRS outbreak. Taken together, our information from this study will provide insight into the establishment of an effective control strategy for PRRS on the field.

• Korean Journal of Veterinary Service
• /
• v.18 no.2
• /
• pp.133-151
• /
• 1995

During 2 years from Octorber 1992 to April 1994, prevalence of general respiratory diseases and atrophic rhinitis in the pig herds located in the Western Chungnam was investigated, and isolation of B. bronchiseptica was attempted for the pigs manifested with the clinical signs of atrophic rhinitis(AR). The isolates were characterized and identified in aspects of biochemical properties, antigenicity, drug sensitivity and pathogenicity. The results obtained through the experiments are summarized as follows; 1. During 2 years of investigation, the overall prevalence of the general respiratory diseases in the pi8 herds in Western Chungnam was 35.3%, consisting of 35.1% in the pig farms and 38.8% in a slaughter house. The prevalence by age groups accounts for 9.2% in adults, 44.7% in rearings and 25.3% in sucklings. By farm size, The highest prevalence of 56.5% was observed in the smallest farm with 1 to 200 heads. 2. The prevalence of clinical cases of artrophic rhinitis was recorded by 12.7% in the group that is the sows and piglets vaccinated, 28.9% in the group that is the sows only vaccinated and 39.8% in the group of the non-vaccinated groups. In the slaughter house, 53(24.8%) of 214 pigs examined exhibit the AR lesions. 3. A total of 189 strains of B. bronchiseptica were isolated from the pig herds. Isolation rates were 12.6% in the group that is the sows and piglets vaccinated, 34.1% in the group that is the sows only vaccinated and 45.7% in the group of the non-vaccinated groups. Isolation rate in the specimen from the slaughter house was 93( 43.5% ) of 214 pigs examined. Of the AR-non-vaccinated group, the piglets aged bet- ween 61 to 90 days revealed the highest isolation rate of 58.5%. 4. The titers of antibody against B. bronchiseptica were measured by tube agglutination test. The group that is the sow and piglet-vaccinated showed the highest titer of 640-2, 560 in sow and 640longrightarrow5, 120 in piglet. The group that is the sows only-vaccinated revealed 640-2, 560 in sows and 640-1, 280 in piglets. Both of the vaccinated groups showed 100% positive reaction. The group of the non-vaccinated sho-wed relatively lower titer of 0-1, 280 in both of sows and piglets. The positive rate of the sera obtained from the slaughter house was 53.3% with the antibody titer of 0-1, 280. 5. Biochemical and serological properities of 189 isolates were very similar to those of the reference B. bronchiseptical phase I type, indicating that most of isolates are B. bronchiseptica phase I type. 6. In antimicrobial drug susceptibility, 87.3% of 189 isolates was susceptible to chloramphenicol, 79.9%, to amikacin, 64.6%, to cephalothin and less than 35.4% to others. 7. In agar-gel immunodiffusion and SDS-PAGE analysis, the isolates presented the identical antigenicity and protein profiles to the reference standard strains. 8. The whole cells and bacterial filtrates of the isolates were inoculated to guinea pigs and mice. The isolates showed the hish pathogenicity and dermonecrotoxiciy.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.6
• /
• pp.903-910
• /
• 2015

To maintain a predominantly pasture-based system, the large herd milked by automatic milking rotary would be required to walk significant distances. Walking distances of greater than 1-km are associated with an increased incidence of undesirably long milking intervals and reduced milk yield. Complementary forages can be incorporated into pasture-based systems to lift total home grown feed in a given area, thus potentially 'concentrating' feed closer to the dairy. The aim of this modelling study was to investigate the total land area required and associated walking distance for large automatic milking system (AMS) herds when incorporating complementary forage rotations (CFR) into the system. Thirty-six scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as moderate; optimum pasture utilisation of 19.7 t DM/ha, termed as high) and 6 rates of replacement of each of these pastures by grazeable CFR (0%, 10%, 20%, 30%, 40%, 50%) were investigated. Results showed that AMS cows were required to walk greater than 1-km when the farm area was greater than 86 ha. Insufficient pasture could be produced within a 1 km distance (i.e. 86 ha land) with home-grown feed (HGF) providing 43%, 29%, and 22% of the metabolisable energy (ME) required by 400, 600, and 800 cows, respectively from pastures. Introduction of pasture (moderate): CFR in AMS at a ratio of 80:20 can feed a 400 cow AMS herd, and can supply 42% and 31% of the ME requirements for 600 and 800 cows, respectively with pasture (moderate): CFR at 50:50 levels. In contrast to moderate pasture, 400 cows can be managed on high pasture utilisation (provided 57% of the total ME requirements). However, similar to the scenarios conducted with moderate pasture, there was insufficient feed produced within 1-km distance of the dairy for 600 or 800 cows. An 800 cow herd required 140 and 130 ha on moderate and high pasture-based AMS system, respectively with the introduction of pasture: CFR at a ratio of 50:50. Given the impact of increasing land area past 86 ha on walking distance, cow numbers could be increased by purchasing feed from off the milking platform and/or using the land outside 1-km distance for conserved feed. However, this warrants further investigations into risk analyses of different management options including development of an innovative system to manage large herds in an AMS farming system.

• Journal of the korean veterinary medical association
• /
• v.16 no.3
• /
• pp.129-136
• /
• 1980

Present experiments were conducted to classify the epizootic skin diseases of swine and determine the etiological agent of swine parakeratosis in Korea. Twnty-three herds of swine with skin disease in Gyongbug prefecture were examined clinicopathologicall

• Journal of the korean veterinary medical association
• /
• v.15 no.4
• /
• pp.195-202
• /
• 1979

Samples of blood from 264 health adult Holstein cows were examined to determine the variation of blood composition during pregnancy and early lactation. The animals were selected from herds in Jeonnam area. The results were summarized as below: 1. The num

• Journal of the korean veterinary medical association
• /
• v.22 no.10
• /
• pp.633-637
• /
• 1986

A total of 1.252 quarters milk sample (998 from 267 cows of 37 herds and 254 of received from dairyfarms) in Chunbuk province were classified as clinical and subclinical group by CMT and RBU test. Of these positive sample, the mastitic agents were isolate

• Korean Journal of Veterinary Service
• /
• v.22 no.4
• /
• pp.371-375
• /
• 1999

Total 1,434 sera collected from 72 pig farms were tested for the detection of porcine reproductive and respiratory syndrome (PRRS) virus antibodies. The overall seroprevalence of PRRS virus antibodies was 49.3% (707/727). Of 72 farms tested 59 (81.9%) farms had at least one or more than one pigs with PRRS virus antibodies. The seroprevalence of PRRS virus antibody varied with age. Seroprevalence of PRRS virus antibody in 1 to 30-day-old, 31 to 40-day-old, 41 to 50-day-old, 51 to 60-day-old, and over 61-day-old pig were 27.4%, 52.3%, 57.9%, 52.7%, and 68.2%, respectively. Gilt showed relatively higher seroprevalence (61.2%) than sow (29.2%) and boar (38.3%). In most farms, the infection of PRRS virus was chronic and confined to grower or finisher. This pattern of infection suggests that partial depopulation of the infected herds appears be one of the measures to eradicate the PRRS virus infection. High seroprevalence of the PRRS virus antibody in gilts and boars indicates that the infected gilts and boars in the breeding farms are the major source of the PRRS virus infection, and also play an important role in spreading the PRRS virus between fan mates or herds.

• Journal of Animal Science and Technology
• /
• v.58 no.12
• /
• pp.41.1-41.7
• /
• 2016

Background: Over two decades of observations in the field in South East Asia and Hawai'i suggest that majority of the commercial dairy herds are of black hair coat. Hence a simple study to determine the accuracy of the observation was conducted with two large dairy herds in Hawaii in the mid-1990s. Methods: A retrospective study on longevity of Holstein cattle in the tropics was conducted using DairyComp-305 lactation information coupled with phenotypic evaluation of hair coat color in two large dairy farms. Cows were classified into 3 groups: a) black (B, >90%); b) black/white (BW, 50:50) and c) white (W, >90%). Cows with other hair coat distribution were excluded from the study. In farm A, 211 out of 970 cows were identified having 4 or more lactations. In farm B, 690 out of 1,350 cows were identified with 2 or more lactations for the study. Results: The regression analyses and the Wilcoxon-Log-rank test for survival probability showed that Holstein cattle with 90% black hair coat had greater longevity compared to Holstein cattle with 90% white hair coat. Conclusions: This study suggests that longevity of Holstein cattle in tropical regions was influenced by hair coat color and characteristics.

• Korean Journal of Veterinary Service
• /
• v.27 no.3
• /
• pp.239-247
• /
• 2004

Classical swine fever (CSF) was confirmed in 19 herds in Jeunbuk provence (Iksan, Gimje, Wanju, Buan, and Jangsu) in Korea between March and May, 2003 and 10,263 pigs were slaughtered. Pigs contacted with CSF virus in primary outbreak farm show fever, reduced appetite, arched back and chill in company with sever respirative sign and then most infected farms also were observed to fever, reduced appetite, sudden death, and leukopenia (101 pigs). In order to detecting infectious pig with CSF virus, A total of 555 pigs were inspected in 65 herds and blood samples were collected and serological test (ELISA), antigen ELISA, and reverse transcription-polymerase chain reaction (RT-PCR) had been done. Positive rate were $74\%$ (410 pigs) in antibody ELISA, $2\%$ (11 pigs) in antigen ELISA and $33\%$ (182 pigs) in RT-PCR, respectively. As shown that the RT-PCR was useful than the ELISA for determining CSF virus in blood, meat, and other organs.

• Korean Journal of Veterinary Service
• /
• v.27 no.1
• /
• pp.89-94
• /
• 2004

Total 2,451 sera collected from pig farms nationwide were tested for the detection of porcine reproductive and respiratory syndrome(PRRS) virus antibodies. The results were analyzed between different geographic regions, types of breeding pigs, and different years. The overall seroprevalence of PRRS virus antibodies for 3 years was 32.4%(705/2,451). The seroprevalence of PRRS virus antibodies in years 2000, 2001, 2002, and 2004 was 33.4% (284/850), 38.6%(291/754), 33.3%(155/466), and 17.1%(65/381), respectively. The seropevalence of PRRS virus antibody in sow in years 2000, 2001, 2002 and 2003 was 31.7%, 28.4%, 29.6%, and 13.4%, respectively. The seropevalence of PRRS virus antibody in gilts in years 2000, 2001, 2002 and 2003 was 36.6%, 67.4%, 54.7%, and 33.9%, respectively. The seropevalence of PRRS virus antibody in boars in years 2000, 2001 and 2003 was 45.7%, 36.4%, and 100%, respectively. No boar serum sample was submitted for the diagnosis of PRRS virus antibody in the year 2000. High seroprevalence of the PRRS virus antibody in sow, gilts and boars indicates that the infected breeding pigs are the major source of the PRRS virus infection, and also play an important role in spreading the PRRS virus between fan mates or herds.