The sensitivity of an indirect enzyme-linked immunosorbent assay (ELISA) for bovine IgG serum antibody to Pasteurella haemolytica was compared with that of an indirect hemagglutination (IHA) test. Pasteurella haemolytica serotypes were grown in a chemically defined cell culture medium, and soluble antigens released into the growth medium were used in the ELISA and IHA test. An ELISA with serotype-1 antigen consistently detected antibody in sera that were positive by IHA test (correlation, 99%). Sera reacting with serotype-1 ELISA antigens also reacted with ELISA antigens prepared from other serotypes. Although ELISA titers determined by the 2 methods were approximately linear. Titer increases detected in paired serum samples by either test were similar. The ELISA was more sensitive than was the IHA in detecting colostral IgG antibody in serum of newborn calves. The ELISA uses a simple, stable antigen preparation and detects antibody to P haemolytica serotypes that commonly infect cattle.

An ELISA was used to detect IgG, IgM, and complement (C3) on the surface of canine erythrocytes. Erythrocytes were placed in wells of a microtitration plate and incubated with affinity purified, alkaline phosphatase-conjugated anti-canine IgG, IgM, or C3. Results of the ELISA were compared with the direct antiglobulin test (DAT) by preparing standard reference curves from canine blood type A erythrocytes that had been incubated with serial dilutions (1:2 to 1:8,192) of canine anti-A serum. The ELISA detected increased erythrocyte-bound immunoglobulin and complement at two- to fourfold dilutions greater than thoe required for positive results with the DAT. The ELISA required small sample and reagent volumes and detected lower concentrations of immune components than did the DAT.

The changes in serum total protein and immunoglobulin levels, and BVD, IBR and PI-3 viral neutralizing antibody titers in colostrum-conferred Korean native calves during the first 12 weeks postpartum were studied. The mean concentration of total protein, total immunoglobulin, IgG, IgM and IgA in sera of 9 calves at birth were 3.8 +- 0.5g/dl, 0.27 +- 0.15mg/ml, 0.06 +- 0.08mg/ml, 0.21 +- 0.11mg/ml, and extremely low concentration, respectively. Serum total protein level reached a maximum at 20 hours after birth, total immunoglobulin, IgG and IgM levels at 24 hours, and IgA level at 28 hours, respectively. Serum IgA level reached a minimum at 4 weeks old, IgM level at 5 weeks, total immunoglobulin level at 8 weeks, and IgG level at 10 weeks, respectively. After then those levels had begun to increase, but total protein level was still decreasing at 12 weeks old. The half-lives of IgG, IgM, and IgA were 21.1 days, 4.0 days, and 2.6 days respectively. In 10 Korean native cows immediately after parturition, serum neutralizing antibody titers specific to BVD, IBR and PI-3 virus were 8.7 +- 1.5 log2, 5.7 +-1.2 log2, and 6.8 +- 1.0 log2, respectively. And colostral neutralizing antibody titers against BVD, IBR, and PI-3 virus were 10.1 +- 1.4 log2, 6.8 +- 1.3 log2, and 7.8 +- 1.7 log2, respectively. Before suckling the colostrum, SN antibody titers against BVD, IBR, and PI-3 virus were undetectable from all of 9 Korean native calves. Nevertheless SN antibody titer against BVD virus reached a maximum level (9.2 +- 0.6 log2) at 24 hours after birth, that against IBR virus (6.1 +- 1.0 log2) at 20 hours after birth, and that against PI-3 virus (6.8 +- 0.9 log2) at 32 hours after birth, respectively. In 12 weeks old calves, the SN antibodies against BVD and IBR virus were still decreasing, but that against PI-3 virus reached a minimum at 10 weeks, and increased after 12 weeks of age. The half-lives of SN antibodies against BVD, PI-3 and IBR, virus were 16.0 days, 22.6 days, and 25.5 days, respectively.

The levels of the serum and colostral total protein and immunoglobulins of the Korean native cows immediately after parturition and colostrum-conferred passive immune status of the Korean native calves were studied, and the results obtained were summarized as follows: The mean total protein, total immunoglobulin, IgG, IgM, and IgA concentrations in sera of 10 Korean native cows immediately after parturition were 6.8 +- 0.4g/dl, 24.39 +- 3.41mg/ml, 19.49 +- 2.70 mg/ml, 4.56 +- 1.14mg/ml, and 0.35 +-0.08 mg/ml respectively. And the mean total protein, total immunoglobulin, IgG, IgM, and IgA concentrations in colostrum were 15.0 +- 1.1 g/dl, 116.13 +- 23.07mg/ml, 101.51 +- 22.59mg/ml, 9.46 +- 1.99mg/ml, and 5.17 +- 1.59mg/ml respectively. The mean concentrations of total protein and immunoglobulins in colostrum were 2.1 times to 14.8 times higher than those in serum. The mean concentrations of total protein, total immunoglobulins in colostrum were 2.1 times to 14.8 times higher than those in serum. The mean concentrations of total protein, total immunoglobulin, IgG, IgM and IgA in sera from 211 Korean native calves at 2 days old were 6.7 +- 0.9g/dl, 35.74 +- 9.56mg/ml, 29.06 +-8.07mg/ml, 4.91+-2.99mg/ml, and 1.9 +- 0.99mg.ml respectively. Although the calves had been suckled the dam's colostrum, each of calves was considerably various in levels of serum total protein and immunoglobulins and 16.1 percent of the calves were in a state of hypoglobulinemia

The effects of the serum total protein and immunoglobulin levels of the colostrum-conferred Korean native calves at 2 days of age on the disease incidence during the suckling period were studied. Serum total protein, total immunoglobulin, IgG, and IgM levels of 6 Korean native calves died from septicemia were lower than those of calves survived (p0.05). Korean native calves having low serum total protein and immunoglobulins were affected with diarrhea earlier in life, when compared with calves having high serum levels (P0.05). Korea native calves having low serum total protein were affected with bronchopneumonia earlier in life, when compared with calves having high serum levels (P0.05). Korean native calves having low serum neutralizing antibody titers to bovine viral diarrhea virus had high incidence rate of BVD, when compared with calves having having high serum neutralizing antibody titers (P0.05)