Induced sero-conversion in heifers with a field strain of bovine pestivirus - a comparison of methods and doses [cattle]
1990
Cook, L.G. (New South Wales Agriculture and Fisheries, Trangie (Australia). Agricultural Research Cdentre) | Littlejohns, I.R. (Unaffil.) | Jessep, T.M. (New South Wales Agriculture and Fisheries, Goulburn (Australia))
Losses from pestivirus infection in a closed herd of Angus cattle occurred over several years. In order to prevent further losses, controlled exposure of non-pregnant heifers to pestivirus from viraemic carrier animals was undertaken. The results for subcutaneous inoculations showed that the 50 percent infectious dose for cattle was not distinguishable from that determined in cell culture. Inoculation with a field strain of pestivirus in freeze-thawed serum effectively and safely induced sero-conversion in heifers. Inoculation of all cattle at risk is considered necessary because no secondary transmission from inoculated heifers was observed.
显示更多 [+] 显示较少 [-]