Undetected parasite infections in dairy cattle are costing the global dairy industry billions of dollars every year, according to a scientific review highlighted by MSD Animal Health. The findings show how subclinical parasite burdens can reduce farm profitability even when animals show no obvious signs of disease.

The review, highlighted by MSD Animal Health on 4 June, concludes that the greatest losses are often linked not to severe clinical disease, but to “hidden” infections that gradually reduce productivity. Lower milk yield, poorer feed efficiency, impaired fertility and higher vulnerability to other health challenges can together create a significant financial burden for dairy producers worldwide.

The analysis notes that parasite-related losses are frequently underestimated because infected animals may appear healthy while still producing below their potential. This means producers may miss an important source of lost revenue when assessing herd performance.

The review brings together evidence on both internal and external parasites affecting dairy cattle. It underlines the role of proactive parasite monitoring and control in herd health programmes designed to protect productivity and profitability.

The economic implications go beyond individual farms. Reduced milk production, weaker reproductive performance and higher veterinary costs can affect the efficiency of dairy supply chains, particularly as producers face rising production costs and tighter margins.

The findings suggest that preventive parasite management, supported by routine monitoring and herd-specific risk assessments, could help reduce production losses while supporting long-term herd performance, animal health and welfare.

The announcement accompanies the publication of a comprehensive scientific review evaluating the global economic impact of endo- and ectoparasites in dairy cattle. For dairy producers operating under increasing cost pressure, the findings reinforce the economic value of preventive parasite control as part of long-term herd management.

For further information, please visit MSD Animal Health.