An evaluation of circulating bovine viral diarrhea virus type 2 maternal antibody level and response to vaccination in Angus calves.

摘要: Vaccination against viruses has been shown to help prevent bovine respiratory disease in cattle. However, both passively acquired maternal antibody concentration and calf age have impact the ability of immune system a respond vaccination. The objectives this study were identify evaluate environmental management factors that affect 1) viral diarrhea virus (BVDV) type 2 level, 2) decay rate BVDV 3) responses vaccinations. A 2-shot modified live vaccine was administered 1,004 Angus calves weaned at either initial vaccination (n = 508) or booster 496). Calves averaged 139 d whereas 128 age. Bovine antibodies measured 3 approximately 21-d intervals, serially collected serum samples quantify levels initiation end protocol addition initial, booster, overall protocol. Amount transferred increased as dam from 6 yr (P 0.05). Calf nested within birth year-season affected final response, response level circulating, present time had significant < 0.05) negative effect on (initial response). significantly greater than animals In order for mount an vaccination, circulation need be less 3.12 titers. which reached threshold dependent This information will cattle managers consultants design protocols successfully