titre - in serological reactions involving the use of serial dilutions of antiserum, describes the highest dilution at which the measured effect is detected
I, the undersigned veterinarian, certify that the animals described above meet the following requirements: ... (c) they have undergone, between the first and third month after a primary vaccination or a re-vaccination against rabies, a serological test showing a protective antibody titre of at least 0,5 international units.