Neospora caninum is the parasite that causes neosporosis in cattle and dogs. It is also the leading cause of abortion in cattle. It’s generational, persisting in a herd across generations through congenital transmission. Infected cows continually transfer the parasite to their daughters. It’s a thieving, never-ending gift that costs the U.S. beef and dairy industries $1.3 billion a year.
A 2025 University of Minnesota study found just 29 percent of producers had heard of the parasite. Only 12 percent had discussed it with their veterinarians. Yet the study found evidence of Neospora exposure on every farm. While there’s no vaccine, experts featured in this article offer biosecurity and breeding practices that reduce the risk of exposure.
Source: Bovine Veterinarian, August 17, 2026. Link. For many years, controlling the disease largely meant culling infected cows, an approach that was financially unrealistic for herds with high prevalence. Today, however, widespread use of sexed semen, beef-on-dairy breeding programs and embryo transfer provides opportunities to gradually reduce the number of infected replacement females while maintaining herd productivity.
INSIGHTS: While Neospora is costly and silent, a potential annual loss of $100,000 to $250,000 in a single dairy herd is a good reason to speak up, if not shout. Improving biosecurity is a low-cost start to prevent disease with proven ROI. Identifying infected animals and modifying breeding protocols will take more time. These combined strategies can help improve clients’ bottom lines, which benefits all of us.
Graphic source: Merck Veterinary Manual
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