The U.S. Food and Drug Administration (FDA) has issued an emergency use authorization (EUA) for Zoetis Inc.’s Dectomax/Dectomax-CA1 injectable solution for the prevention and treatment of New World screwworm (NWS) infestations in dairy cattle, except for calves that will be processed for veal. The EUA also authorizes Dectomax/Dectomax-CA1 for the prevention of NWS myiasis in swine, horses at least one year old, sheep except for lactating sheep, and deer.
In September 2025, FDA conditionally approved Dectomax-CA1 for the prevention and treatment of NWS in cattle.
FDA has concluded that, based on the totality of the scientific evidence available, it is reasonable to believe that Dectomax/Dectomax-CA1 may be effective for the indications in the species described above, and the known and potential benefits of the product outweigh its known and potential risks.
Dectomax/Dectomax-CA1 is a single product with one label to reflect the product has:
- Approval (Dectomax) for the treatment and control of certain nematode and arthropod parasites in cattle and swine
- Conditional approval (Dectomax-CA1) for NWS indications in beef cattle
- EUA (Dectomax/Dectomax-CA1) for NWS indications in dairy cattle, horses, swine, sheep and deer
Important food safety information
FDA evaluated relevant human food safety information and concluded that the food products obtained from treated animals are safe for human consumption when the conditions of use granted by the EUA are followed, including the milk discard time and withdrawal periods. Adhering to the milk discard time and withdrawal periods helps avoid unsafe drug residues in animal-derived human foods.
Milk discard time
Milk taken from lactating dairy cows, dry dairy cows and replacement dairy heifers during treatment and for 468 hours (19.5 days) after treatment must not be used for human consumption.
Slaughter withdrawal periods
Producers must wait the specified number of days after the last dose of Dectomax/Dectomax-CA1 before slaughtering treated animals for human consumption:
- Lactating dairy cows, dry dairy cows, replacement dairy heifers: 35 days
- Swine: 24 days
- Sheep: 35 days
- Deer: 35 days
Additional limitations of authorized use
- A withdrawal period has not been established for this product in pre-ruminating calves. Treated calves and calves born to treated cows must not be processed for veal.
- Do not use in horses less than one year old or horses intended for human consumption.
- Not authorized for use in lactating sheep. Use in these sheep may cause drug residues in their milk.
This EUA will be effective until it is revoked or the Health and Human Services Secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use authorization of animal drugs for NWS.
