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, and the results obtained were summerized as follows:
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±0.15㎎/㎖, 0.06±0.08㎎/㎖, 0.21±0.11㎎/㎖, 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±1.5log₂, 5.7±1.2log₂, and 6.8±1.0log₂, respectively. And colostral neutralizing antibody titers against BVD, IBR, and PI-3 virus were 10.1±1.4log₂, 6.8±1.3log₂ and 7.8±1.7log₂, 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±0.6log₂) at 24 hours after birth, that against IBR virus (6.1±1.0log₂) at 20 hours after birth, and that against PI-3 virus (6.8±0.9log₂) 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.
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