Paratuberculosis caused by Mycobacterium avium subspecies paratuberculosis (Mpt) is a chronic infectious enteric disease with deleterious impact on the performance in ruminants. In Korea, ELISA has been introduced to detect antibodies to Mpt in individual cattle. However, comparison study with ELISA has not been studied until now. In total, a panel of 899 serum samples obtained from dairy cattle was analyzed with two commercial ELISAs for Mpt to assess the performance. Two ELISAs employed in this study were both licensed worldwide. Two ELISAs applied onto same serum samples showed the morderate agreement (kappa value = 0.06). There was non-significant McNemar test (p=0.0614) between two ELISA results indicating that each proportion detected by two kits did not differ. In addition, the percent agreement between two ELISA results was turned out to be 96.8% which interpreted excellent reproducibility. It was shown from this study that two ELISAs revealed moderate kappa agreement performance. The implication raised is that when ELISAs as diagnostics are used to detect Mpt in individual cattle, positive reaction by either ELISA should be interpreted as serologically Mpt positive due to presumed low sensitivity of ELISAs and their test agreement being less than 100%.

This study was carried out to determine the effects of beta-carotene on the control of mastitis in dairy cows during the dry period. The relationship between the levels of plasma beta-carotene and the status of udder health in Holstein dairy cows were investigated. Blood samples were collected from 117 cows to compare the levels of plasma beta-carotene in lactating cows. The levels of plasma beta-carotene were 1.82 micro gram/ml in healthy cows(n=65) and 1.12 micro gram/ml in mastitic cows(n=52), respectively(p0.01). In the experiment to compare the level of plasma beta-caroten in the cows at different stages of lactation, the plasma beta-carotene levels were 1.73 micro gram/ml in lactating cows(n

The objective of this study was to investigate the calf death and analyse the causes of the mortality by based on medical records and autopsy findings during 10 years in a large dairy farm. Total of 1,361 calf born and 146 calf dead during the invested period. Mortality rate was 10.7% and showed the big difference by year-specific mortality from 2.8% (4 calves) to 19.2% (28 calves). The highest rate of mortality was 1 week age (18.5%, 27 calves) and followed by 2 week age (11.6%, 17 calves) and mortality of more old calf tended to be reduced. The death less than 4 weeks and 8 weeks of age of the entire mortality accounted for 41.1% (60/146 calves) and 70.0% (102/146 calves), respectively. Causes of calf death were digestive diseases (53.4%), respiratory diseases (17.1%), musculoskeletal disease (8.2%), and systemic disease (8.2%) in order. Specific causes of calf death was highest in enteritis (43.2%), followed by pneumonia (14.4%), sepsis (8.2%) and fractures (3.4%). Seasonally, most of calf death happened in winter (48.6%) and then fall (21.2%). This results showed that enteritis and pneumonia are the main reason of calf death but other reasons were involved in calf death on the based on autopsy finding. On going research relating factors of calf mortality is needed.

This survey was carried out to investigate the seroprevalence of antibodies to Neospora (N.) caninum in dairy cattle raised in Kangwon province in Korea. A total of 349 sera collected from dairy cattle were tested for N. caninum antibodies using an indirect immunofluorescent antibody test (IFAT). Ninety six (27.5%) dairy cattle were positive by IFAT. Seroprevalence of cows was 28.9% (91/315) and seroprevalence of boars was 14.7% (5/34). The seroprevalences of cows were increased according to the ages from 19.6% in cows less than 2 year-old to 50.0% in cows more than 7 year-old. Among the seroprevalences of cattle according to the raised areas, five counties or cities, Wheongsung was 34.6% (27/78), Wonju was 29.3% (46/157), Hongcheon was 28.9% (13/45), Chuncheon was 15.0% (3/20) and Cheolwon was 13.3% (2/15). It was proved that dairy cattle raised in Kangwon provinces exposed extensively and seriously to N. caninum.

The trend in the prevalence of bovine tuberculosis (BTB) in Korean dairy cattle was investigated in relation to test programs used between 1961 and 2004, during which a total of 8,961,061 dairy cows were tested and 10,248 confirmed to have BTB. The annual prevalence increased in the late 1960s, then decreased during the 1970s and 1980s, and started to increase again from the late 1990s. It seemed that the prevalence varies according to the different test program used. The prevalence of BTB was higher when the tests were performed with heat-concentrated synthetic medium (HCSM) or purified protein derivative (PPD) tuberculin alone compared to that when using combined HCSM and PPD tuberculin testing.