The current standard solutions for somatic cells used for calibration of electronic somatic cell counts as reference material in raw milk are preserved with bronopol, boric acid, sodium azide, or potassium dichromate, and have a shelf-life of only up to 6 days at 4 ± 2℃. In the present study, a set of somatic cell standard solutions (SCSS) with a stability of 5 months for calibration of electronic instruments was developed. Somatic cells collected from cow’s milk and stored in a bulk tank at a dairy plant were treated with 10% formaldehyde in order to improve stability, and then separated by centrifugation. The resulting somatic cell suspension was preserved with glycerin, thimerosal, and dimethyl sulfoxide, and diluted in 3% processed skim milk solution ranging from 200,000～250,000 (low level), 350,000～ 450,000 (medium level), and 550,000～650,000 (high level) cells/㎖. Each SCSS was verified by direct microscope somatic cell counting (DMSCC), C-reader, and commercial standard samples. The average somatic cell count determined by DMSCC was 248, 214, 226 × 103 cells/㎖, 436, 382, 420 × 103 cells/㎖, and 612, 595, 609 × 103 cells/㎖. The coefficient of variation representing the repeatability of DMSCC decreased as the number of cells increased, and was <10.0% in almost all SCSS samples (range 4.6～7.1%). No statistically significant difference in somatic cell concentration was observed after storage at refrigeration temperature (2～6℃) over a period of 22 weeks (5 months). The stabilized SCSS may be useful as a reference material for determination of somatic cell count and quality control in testing of bovine raw milk.

Bovine brucellosis causes abortion and infertility. The authors conducted this study in order to determine pathological lesions of Korean native cows and fetuses who received experimental vaccination with Brucella abortus RB51 and were challenged with Brucella abortus 2308. Gross and histopathological lesions in endometrium and placenta were observed in cows of the vaccinated group. Twenty-five percent of pregnant cattle in the vaccinated group showed endometritis and placentitis, which was three times lower, compared with the non-vaccinated group. The pathological lesions in the uterus and placenta in both groups were consistent with previous reports. Therefore, vaccination in heifers using Brucella abortus RB51 may not provide adequate protection against infection with Brucella abortus virulent strain.

The sensitivities of PrP Sc detection methods, western blotting (WB), immunohistochemistry (IHC) and protein mis-folding cyclic amplification (PMCA) techniques were compared from brains, spleens and blood of mice challenged with PrP Sc of murine-adapted BSE strain 301C. PrP Sc was detected in the spleen from 30 dpi by IHC and at 60 dpi by WB. At 30 dpi, disease-specific signals of PrP Sc was observed in only two follicles of a single spleen. PrP Sc was detected in spleen at 10 dpi with PMCA after 5 rounds of amplification. Clinical signs were obviously shown from 240 dpi, and coincided with first detection of PrP Sc in brains by WB, IHC and PMCA after one round amplification. In addition, PrP Sc was also detected in blood at 60, 180 and 240 dpi with PMCA after 5 rounds of amplification. The FDC-M1 epitope, which appears in immature FDCs, and PrP Sc were detected in follicles first at 30 dpi, whilst the FDC-M2 epitope of mature FDCs was detected at 60 dpi. More FDC-M2 epitope and PrP Sc were detected in follicles as disease progressed. The CD21/35 epitope is expressed on both FDCs and germinal center B cells. The pattern of CD21/35 expressing cells was similar to but less dominant than that of FDCs.

Grossly, a lot of soft white nodules, 0.5～1.5 cm in diameter, were randomly scattered in liver of a slaughtered Korean Native Cattle. The surface of liver was roughened by those nodules. Histopathologically the nodules were consisted of numerous mature blood vessels, which had variable size and wall thickness, and which were encircled by much connective tissue. Masson's trichrome stain clearly revealed the proliferated blood vessels and perivascular stroma and, immunohistochemical staining revealed that endothelial cells of proliferated blood vessels were positive for Von Willebrand Factor. Based on gross and histopathological lesions, and immunohistochemical staining, the case was confirmed as hepatic vascular hamartoma and it is the first case report in Korea, as far as we know.