Persistence of Maternal Antibodies Against Foot-and-Mouth-Disease Virus in Colostrum Fed Calves Born from FMD Convalescent Vaccinated Dams Under Natural Conditions

Abstract

Foot-and-mouth disease (FMD) is an economically devastating viral disease of cloven-footed animals that is primarily controlled through mass vaccination and bio-security measures. It is critical to know the duration of persistence of colostral antibodies known to interfere with the vaccine-induced antibody response to determine the optimal age for neonatal calves to be vaccinated for the best vaccinal efficacy. Serum samples were collected from the convalescent-vaccinated cattle (dam) at the time of calves' birth, as well as from each newborn calf four, thirty, sixty, and ninety days later. The duration of maternal antibodies against FMD virus (FMDV) structural proteins (SPs) and non-structural protein (NSP) 3AB3 in colostrum-fed calves born to dams that were vaccinated/convalescing was investigated. On calving day, 35 (92.11%) of the 38 dams tested positive for anti-3AB3 NSP antibody, while 38 (100%), 31 (81.58%), and 33 (86.84%) tested positive for anti-SP antibody log10 titre 1.8 of FMDV serotypes 'O,' 'A,' and 'Asia1,' respectively.Anti-NSP and anti-SP antibodies titre of FMD virus in serum were detected in colostrum fed calves from FMDV vaccinated dams by the fourth day and then declined to almost undetectable levels by the 90th day postpartum. The current study suggests that FMDV antibody is passively transferred and persist between 30-90 days in colostral-fed calves and nearly disappears by the 90th day after birth. Therefore, in primary vaccination regimens, the first dose of FMD vaccine may ideally be administered in caves after 3 months of age, followed by a subsequent boost 28 days later.