National Organic Standards Board Recommends Reinstating Ivermectin for Organic Dairy in Response to Screwworm Threat
The National Organic Standards Board (NOSB) has recommended that ivermectin, a synthetic parasiticide, be reinstated on the National List of substances allowed in organic livestock, specifically for dairy and breeding animals. This recommendation comes in response to the spreading New World screwworm (NWS) threat across Texas, New Mexico, and Arizona. The NWS, eradicated in the U.S. in 1966, reappeared in June 2026 and has seen a significant increase in confirmed cases. The FDA authorized over-the-counter ivermectin injections for emergency use to prevent NWS in cattle, excluding lactating dairy cows. The NOSB's proposal would allow ivermectin use only for NWS and would reduce the exclusion period for milk from treated organic dairy cows from 12 months to 90 days. Ivermectin was removed from the National List in 2019 due to environmental toxicity concerns and the availability of other parasiticides. The USDA's National Organic Program has not yet declared the outbreak an emergency treatment program, which ...