RESUMEN
Objective: detecting of seropositive cattle to BVD virus by indirect ELISA using milk and serum samples from individual cows, comparing the use of milk instead of blood serum for determining the BVDV infection in cattle herds
Design: bovine viral diarrhea seroprevalence survey in cattle using milk and serum ELISA by retrospective study
Animals: one hundred and eighty eight milky cows and 45 calves 0.5-2 years old [Native and hybride] from 24 cattle herds in subord of Urmia
Procedure: preparing serum and skim milk for detection of anti- BVDV 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 equal or higher than 2.5 time OD of reference negative control serum and milk, considered as ELISA-positive. The data obtained from 188 matched sets of milk and serum were statistically compared with each other to determine the percentage of correlation between them
Statistical analysis: student's t and chi square tests
Results: out of 188 pairs milk and serum, 52 cases [27.65%] of milk and 59 [31.38%] of serum samples were ELISA positive. The data showed 96% correlation between the results of milk-ELISA and serum-ELISA
Conclusion: the present study showed that milk-ELISA is well performed in compared with serum-ELISA test. However the output of milk-ELISA was 3.72% less than serum-ELISA in detection of animals infected with BVDV, but on significant differences was found between the results gained by milk-ELISA [27.65%] and serum-ELISA [3 1.38%] test by student's t-test. Therefore, the milk can be used instead of serum in ELISA for detection of infected herds as a screening test