Abstract.Interference caused by maternal antibodies is considered a major cause of canine parvovirus (CPV) vaccination failure. In this study, an immunoblot clinic-based enzyme-linked immunosorbent assay (ELISA) method was used to detect CPV antibodies in sera of pregnant bitches and their offspring to study the response of pups to vaccination. With a easily accessible procedure for CPV antibody determination, the veterinarian should be able to gauge the response of pups after vaccination. The validity of the technique was tested in parallel against the standard hemagglutination inhibition (HI) test. Results of the ELISA were correlated with those of the standard HI method for quantification of CPV antibodies. With the ELISA, successfully immunized pups were identified, allowing for a more reliable and cost-effective program of vaccination. This simple clinicbased test could be used for the assessment of vaccination status of pups during the critical phase of 6 to about 16 weeks of age. This study is the first in which vaccination response to CPV in pups was followed, using a clinic-based ELISA for CPV antibody monitoring.Maternal antibody transfer in the dog occurs primarily by intestinal absorption from the colostrum during the initial 2 days of the pup's life.1 Interference by maternal antibodies is regarded as a major cause of canine parvovirus (CPV) vaccination failure in young dogs. 1,7 Attempts to develop immunization strategies to overcome this problem have to date been based on administration of multiple vaccinations from about 6 weeks of age until about 16-18 weeks of age. 2In this study, we tested an immunoblot clinic-based enzyme-linked immunosorbent assay (ELISA) method to semiquantitatively assay CPV antibodies in sera of pregnant bitches and their offspring to study the kinetics of maternal antibodies in pups and the response of pups to vaccination. With an easily accessible inclinic procedure for CPV antibody determination, it should be possible to monitor response of pups after vaccination with CPV. The validity of the technique was tested in parallel with the standard hemagglutination inhibition (HI) test. Materials and methodsAnimals. Ten pure-bred, pregnant beagle dogs a were used in this study. The bitches were allowed to whelp normally, and 4 pups were selected at random from each litter for antibody studies.