Aim: The aim of this study was to investigate the effects of sex on the humoral immune response induced in cattle by vaccination against foot-and-mouth disease virus (FMVD).

Materials and Methods: Cattle (n=252) were classified into six groups according to the age (0-11 months, 12-35 months, and >35 months) and sex (male-female). Animals in each group were vaccinated with oil-adjuvanted bivalent vaccine (O₁ Manisa, A₂₂ Iraq FMDV strains). Solid-phase competitive ELISA was used to measure antibodies produced in vaccinated cattle.

Results: Serotype O antibody was detected in 86 (68.2%) and serotype A antibody in 90 (71.4%) of 126 male sera. In female animals, serotype O antibody was detected in 106 (84.1%) and serotype A antibody in 112 (88.8%) of 126 sera. Protective level of antibody against serotype O was detected in 89 (70.6%) and serotype A in 98 (77.7%) of 126 female sera. Protective level of antibody against serotype O antibody was detected in 67 (53.1%) and serotype A in 81 (64.2%) of 126 male sera. The differences between the level of protective antibody against both serotype O (P=0.0063) and serotype A (P=0.0259) in female and male animals were statistically significant.

Conclusions: Results showed that female animals vaccinated with oil-adjuvanted bivalent vaccine (containing O₁ Manisa, A₂₂ Iraq FMDV strains) had higher antibody responses than male animals. In order to elucidate difference between immune response of male and female animals to FMD vaccination more studies are needed.