Abstract Background In goat kids, choosing the appropriate age to administer the first dose of goat pox disease (GTP) vaccine requires knowing when maternal antibody decline concentrations. Objective Determine the persistence of maternal antibodies against goat pox virus (GTPV) in goat kids. Animals Twenty Saanen goat kids from birth to 120 days old. Methods In 2 groups, including: control (receiving colostrum from nonvaccinated does) and treatment (receiving colostrum from vaccinated does). On zero, 3, 7, 14, 21, 28, 42, 56, 70, 100 and 120 days after the birth, virus neutralization test was used to measure the serum concentration of antibodies against GTPV. Results At the age of 56 days, the first seronegative goat kids (n = 2) were recorded in the treatment group. At the age of 120 days, all the goat kids in the treatment group were seronegative. The average virus neutralization index (VNI) of the goat kids became negative at the age of 100 to 120 days. All goat kids in the control group were negative at all times. Conclusions and Clinical Importance One hundred to 120 days of the age seems to be the time to administer the first GTP vaccine in the goat kids with passive immunity against goat pox.