No abstract

From three commercial Friesian-Holstein dairy herds located in three different provinces of Egypt at El-Fayoum, EL-Ismailia, and EL-Beheira; a total of 183 paired serum and milk samples were collected on the same occasion and 23 Bulk Tank Milk (BTM) samples were collected for about a year. Samples were tested and evaluated to monitor the immune status of vaccinated cattle against Foot and Mouth Disease (FMD) virus (strain O1/93/ Aga / Egypt). All samples were subjected to Indirect Enzyme-linked immunosorbent assay (ELISA) test and Serum neutralization test (SNT) for the detection of specific antibodies. Although Milk is easier and more acceptable than blood sampling for surveys in many situations, results have revealed a significant correlation (r>6, P<0.01) between individual serum and milk titers. BTM permit an adequate determination of immune status representing individual milk samples in dairy herds, it permits an adequate determination of Herd Protection level (HPL) but with different cut-off values according to different conditions of management. In addition, the number of vaccination was adopted in each herd; vaccination of dairy herds for three times annually is the number of choice for sufficient economic protective antibody titer all round the year.