Antibody Decrease During the Peripartum Period: its Impact on Enzootic Bovine Leukosis Diagnosis

Abstract

The goal of this work was to characterize the evolution of specific anti-BLV antibody titers during the peripartum period in dairy Holstein cows. The experimental design involved 3 groups of 5 cows each characterized as negative, slight positive and strong positive. All animals were bled every 20 days, from -50 to +50 days (0 = calving), and serum samples were analyzed by a commercial ELISA test. The strong positive group remained with a positive diagnosis along all test observations, as the negative group remained as negative. However, in the slight positive group the ELISA optical densities decreased between 40% and 60% of the initial levels and all the animals that were initially positive became negative in the peripartum period. Overall these results show that in the peripartum the physiological decrease in specific anti-BLV antibodies in the slight positive group may produce false negative results from day -20 to +60, indicating that sample extraction should be avoided for serologic diagnosis of EBL during this period.