Efficacy of colostral immunoglobulins for therapeutic and preventive treatments of calf diarrhea.

Pooled colostral milk samples were collected from apparently healthy Holstein cows. Immunoglobulin (Ig) was partially purified from the colostral milk and concentrated by freeze drying. The Ig powders had neutralizing antibody titers of 1:6,250 to 1:31,250 against bovine rotavirus (RV), and reacted with four RV proteins of VP2, VP4, VP6, and VP7. No therapeutic effect of Ig powder showed on clinically serious diarrhea with RV in dairy and beef calves. However, the Ig powder had a preventive effect on the diarrhea in beef calves when it was given soon after calving.

Antibody responses of swine to type A influenza viruses in the most recent several years.

A serological survey was conducted on 4,080 swine sera collected for the years 1985-90. The swine sera positive to A/New Jersey/8/76 (swine type H1N1) strain were observed in annual (10-20%) and monthly (20-40%) incidences during the observation period except for occasional months. Antibodies to recent human H1N1 viruses in swine were recognized in relation to the human H1N1 influenza epidemics. Antibody responses of swine to human H3N2 strains appeared irrespective of human epidemics with the virus in the years 1985-87. However, in 1988 almost no antibodies to three human H3N2 isolates of 1983-88 were observed for this year except a few months though the human epidemic occurred in the area. Although in 1989-90 many swine had antibodies to the three strains in the percentage of 3 to 35, no antibody to the latest isolate, A/Hokkaido/20/89 (H3N2), was found for almost all the months of both years. These findings differed markedly from the possible relationship between the prevalence of H3N2 virus-antibodies in swine and the human influenza epidemics, which were described previously in many reports including our studies.