ORIGINAL PAPER Seroprevalence of Neospora caninum antibodies in beef cattle in three southern states of Mexico Zeferino Garcia-Vazquez & Rodrigo Rosario-Cruz & Felix Mejia-Estrada & Ivan Rodriguez-Vivas & Dora Romero-Salas & Manuel Fernandez-Ruvalcaba & Carlos Cruz-Vazquez Accepted: 15 October 2008 / Published online: 19 November 2008 # Springer Science + Business Media B.V. 2008 Abstract The aims of the present study were to examine the seroprevalence of neosporosis in beef herds from three southern states of Mexico and determine the association with several risk factors. A cross-sectional serological survey for Neospora cani- num was carried out by sampling a total of 596 animals from 31 herds in Chiapas, Veracruz, and Yucatan States and tested using an ELISA assay (IDEXX) to detect anti-N. caninum antibodies. The overall prevalence was 11.6%, (95% CI: 0.93–0.14), however, the prevalence for Chiapas was 15% (30/200) (95% CI: 0.11–0.21), in Yucatan 11.3% (21/186) (95% CI: 0.07– 0.17) and in Veracruz 8.6% (18/210) (95% CI: 0.05– 0.13). Of the 596 serum samples taken, 578 were from females and 18 were bulls., Only one bull sample was found seropositive from one herd in Veracruz State. The overall herd-prevalence was 70.9% (22/31) (95% CI: 0.53–0.84), and by State was: Chiapas 90% (9/10) (95% CI: 0.60–0.98); Yucatan 72.7% (8/12) (95% CI: 0.39–0.86); and Veracruz 50% (5/10) (95% CI: 0.24– 0.76), respectively. The highest age-prevalences were found in animals 1 yr old (19.4% [95% CI: 0.01–0.35]) and 4 yrs old (19.6% [95% CI: 0.12–0.29]), and the lowest in animals 3 –yrs of age (6.2%,[95% CI: 0.02– 0.20]). No association was found among all the variables tested in this study since most of the ranches have similar management conditions. In conclusion, N. caninum infection is common among beef herds in the Mexican tropics. Keywords Beef cattle . Neospora caninum . Seroprevalence . Mexico Trop Anim Health Prod (2009) 41:749–753 DOI 10.1007/s11250-008-9247-x Z. Garcia-Vazquez (*) : R. Rosario-Cruz : M. Fernandez-Ruvalcaba Centro Nacional de Parasitología Veterinaria. Instituto Nacional de Investigaciones Forestales, INIFAP, Apartado Postal 206, CIVAC, Morelos C.P. 6225, México e-mail: garcia.zeferino@inifap.gob.mx F. Mejia-Estrada Centro Experimental Pichucalco, Chiapas. Instituto Nacional de Investigaciones Forestales, INIFAP, México, México I. Rodriguez-Vivas Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, México D. Romero-Salas Facultad de Medicina Veterinaria y Zootecnia, Universidad Veracruzana, Veracruz, México C. Cruz-Vazquez Instituto Tecnológico El Llano Aguascalientes, A.P. 74-2 Admon, Postal No. 2. C.P. 20041 El Llano Aguascalientes, Ags, México