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Neospora caninum is a protozoan parasite first recognized in dogs in Norway.4 The parasite was isolated into tissue cul-ture and identified as a new genus in 1988.12 Disease was first associated with congenital encephalomyelitis in pup-pies. Subsequently, fetal and neonatal infections were described in cattle, sheep, goats, deer, and horses.6,13,21 In the last decade (2000–2010) neosporosis has emerged as an important reproductive disease in cattle. Most of the studies of N. caninum infections have examined their impact mainly on dairy cattle.10 However, some authors have established that Neospora infections are important in beef herds as well.27,28 A report from 1995 indicated that neosporosis was pres-ent in Argentinean beef and dairy herds. The infection status was corroborated by serological evidence using indirec