Identification of cattle persistently infected (PI) with the Bovine Viral Diarrhoea Virus (BVDV) using a screening method for a control and eradication programme

Abstract

The objective of this study was to identify PI cattle in a closed herd of a capacity of 137 dairy cows (a total of 263 animals of different age). The cattle were divided into three experimental groups. The first group comprised 15 animals tested 10-15 days before parturition. The second group was composed of 14 cows examined 10-15 days after parturition. The third group was made up of 15 cows in full lactation. Two series of blood samples were collected at an interval of 4 weeks (paired samples) from all cows from each experimental group. Blood serums taken from both series of samples were tested by an indirect enzyme immunoassay (ELISA) using the HerdChek* BVDV Ab test kit.

The results obtained in this study indicated the presence of BVD virus infection in the examined cattle. The serum samples taken on the first day of testing were seropositive in 5 animals and suspicious in 1 in the first experimental group, seropositive in 2 animals of the second group and seropositive in 3 and suspicious in 2 animals of the third experimental group.  The serum samples collected on day 28 tested seropositive in 5, 2 and 4 animals in the first, second and third experimental groups, respectively.

The samples of cattle that were found to be seronegative in both tests (i.e. on days 1 and 28) were tested by the enzyme immunoassay method (ELISA) using the HerdChek* BVDV Ag/Serum Plus test kit specifically designed for detecting BVD virus antigens. BVD virus antigens were not confirmed in any of the examined cattle.