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Objective: Detecting seropositive BHV-l infection in cattle by indirect ELISA using milk and serum samples from individual cows; comparing the use of milk instead of serum for determining the BHV-l infection in cattle herds.
Design: Retrospective study.
Animals: A total of 140 cows and 50 bulls from 22 herds.
Procedures: Preparing serum and milk for detection of anti BHV¬1 antibody by indirect ELISA. The sera were diluted 1 :25 and the milk samples were used as undiluted. The sera and milk which had OD higher than 2.5 time OD of reference control serum considered
as ELISA positive. The data obtained from 140 matched sets of milk and serum were compared with each other to determine the percentage of agreement between them.
Statistical analysis: Using of student's t and chi square tests for determine the significant differences between the percentage of milk and serum-ELISA positive.
Results: Out of 140 matched sets of milk and serum, 38 cases (27.15%) of milk -ELISA positive were obtained. The data showed 95% agreement between the results of milk-ELISA and sero¬-ELISA. The males showed higher levels (40%) of BHV-l infection than females (32.1 %).
Conclusion: The present study showed that the milk - ELISA can be used instead of serum-ELISA in detection of infected herds as a screening test. J. Foe. Vet Med Univ. Tehran. 58,3: 157-159, 1003