Health Canada has approved the use of Merck Animal Health’s antibiotic Engemycin DD to treat infections caused by bacteria sensitive to oxytetracycline in cattle, swine and sheep.
Merck Animal Health said in a release Engemycin DD is a Category III antimicrobial drug. Antimicrobial drugs are categorized based on their importance in human medicine, with the highest category of antimicrobials reserved for the treatment of serious infections to preserve their efficacy and limit antimicrobial resistance. Because of this, the use of Category I antimicrobials in livestock is restricted except for extraordinary cases.
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Merck Animal Health said as a Category III antimicrobial, Engemycin DD can offer a new treatment option in livestock. It is also the only short-acting oxytetracycline on the market for livestock, making it ideal for dairy farmers to treat infected cows and have a manageable withdrawal period for milk, the company said.
“The launch of Engemycin DD is significant, especially for dairy farmers in provinces where the use of Category I antimicrobials has been restricted in food-producing animals,” said Ray Reynen, DVM, Veterinary Services, Cattle at Merck Animal Health. “Engemycin DD gives producers a viable option where they have had limited choices for broad-spectrum antibiotics.”
David Wiens, president of Dairy Farmers of Canada said in the release “increasing the diversity of veterinary health care tools available in Canada is essential to positive health outcomes for animals and helping farmers play their part in reducing antimicrobial resistance.”
There has been a shortage of broad-spectrum antibiotic options on the market in recent years as products have been discontinued for sale in Canada. Merck Animal Health said it filed an updated regulatory dossier for Engemycin DD in February 2024. The Veterinary Drugs Directorate granted a priority review given its demonstrated need to the industry and Engemycin DD received market authorization in February 2025.
Engemycin DD is now available for use in Canada. Merck Animal Health said producers can contact their local veterinarian to determine whether Engemycin DD is suitable for the animal to be treated. For more information on Engemycin DD, veterinarians can contact their local Merck Animal Health representative or call 1-866-683-7838.
