FDA Approves Exzolt Cattle-CA1 for Prevention and Treatment of New World Screwworm

On December 4, 2025, the U.S. Food and Drug Administration (FDA) granted conditional approval to Exzolt Cattle-CA1, a fluralaner topical solution from Merck Animal Health, for the use in beef cattle (≥ 2 months of age) and replacement dairy heifers (< 20 months of age). The approved uses include prevention and treatment of larval infestations by New World screwworm (NWS), and treatment and control of cattle fever tick.