Seroprevalence of Zona Pellucida antibodies in some Minnesota swine herds

Serum samples collected from selected swine breeding farms in St.Paul, Minnesota, U.S.A. were screened for zona pellucida (ZP) antibodies by the Enzyme-linked immunosorbent Assay (ELISA) technique. Of the 1865 samples screened, 107, 171, 489, 329, 302 were in the age ranges 0-6, 7-12, 13-18, 19-24, 25-30 and above 30 months of age and the proportions positive for ZP antibodies were 0, 5.26, 9.61, 14.78, 18.84 and 19.21% respectively. A total of 245 (13.14%) of them positive for ZP antibodies and seropositivity increased with age (P 0.10) and there was no interaction between farm of origin and age of animal (P>0.10). The possibility of gential infections contributing to the auto-immunity cannot be ruled out and the association of the antibodies with increased age may be due to infections over a long time. This aspect of immunological infertility should be taken into consideration when investigating infertility in swine herds. (Tropical Veterinarian: 2003 21(1): 42-46)