Reduced egg production with depigmented, chalky deposit, wrinkled and malformed eggs was observed in breeder flocks throughout the country. The disease was identified as Infectious Bronchitis based on serological findings and virus isolation

This paper described the distribution and transmissibility of BLV (bovine leukemia virus), the relationship between antibodies against BLV and lymphocyte count in 313 dairy cattle from 36 herds, the clinical signs and hematological findings of 2 lymphosarcomatous cattle in the northern area of Kyongbuk. Eighty three (26.5%) of 313 cattle from 36 herds were positive for BLV antibodies and 19 (52.8%) of 36 herds were infected with BLV by the immunodiffusion test with BLV-gp antigen. The rate of BLV infection in cattle varied from 9.5 to 87.5% in 19 positive herds, it was higher in herds pastured during summer and included lymphosarcomatous onset than the other and also higher with the age

The frequency of appearance of HI antibody against Japanese encephalitis virus was investigated over the three-year period 1982 through 1984. The sample population consisted of 1306 cattle in Saitama prefecture (located in central Japan), and 536 cattle in Kagoshima prefecture (located in southern Japan). During the study period, there was no significant difference in the average antibody-positive rate between cattle in Kagoshima (68.8 %) and those in Saitama (65.5 %). Variations in the monthly antibody-positive rate and mean monthly antibody titer in the Saitama cattle followed a mountain-like pattern with the peak observed during summer. In the Kagoshima cattle, both parameters also increased in summer and these increases persisted even in winter. The distribution of antibody-positive rate as a function of age ranged from 64.0 % to 82.8 % in Saitama, though no correlation was observed between these two factors. In the Kagoshima cattle, however, the antibody-positive rate increased with age as follows; the values averaged 29.4 % in the one-year-old cattle group, 50.0 % in the two-year-old group, 47.4 % in the three-year-old group and 74.5 % in the four-year-old group. There was no significant correlation between the mean antibody titer and age in either Saitama cattle (15.3-22.5) or Kagoshima cattle (20.0-32.3)

This experiment was carried out to determine the progesterone concentration of bovine plasma by liquid phase double antibody enzyme immunoassay. The optimum conditions of assay-system, double (first and second) antibody and carrier (normal rabbit serum) were investigated. The optimum dilution rate of first antibody, second antibody and normal rabbit serum was 10X10** (3) to 15X10** (3), 20 and 1X10** (3) times, respectively