Neospora caninum, a protozoal parasite, is a common cause of abortion in dairy cattle in North America. Cows that become infected with Neospora appear to remain infected for life. Infection is acquired through vertical transmission (dam to offspring in utero) or horizontal transmission and leads to endemic abortion, with occasional herds reporting abortion storms or outbreaks.2 In addition to the reproductive consequences of infection, in one study of a single large herd, seropositive primiparous animals produced 3.6 lbs less fat-corrected milk than did their seronegative primiparous herd mates.3 The objective of this study was to examined the effect of serologic status for Neospora on production in a large random sample of cattle in eastern Canada.