Calves, antimicrobials, and you: How dairy producers can prevent antibiotic residues in calves

Antimicrobial treatments like antibiotics are an important tool for raising healthy calves. Irresponsible use of these medications is increasingly scrutinized by consumers, media, and regulators, and can have negative impacts on food safety and human health as well as consumer perceptions of dairy farming.

Since not all calves go to a veal barn for finishing – some can go from an auction barn straight to processing -, dairy producers in particular have a key role to play when it comes to ensuring food safety through responsible antimicrobial use in bob calves.


In Ontario, all light calf carcasses (up to 176 pounds) are tested for residues under the provincial Antimicrobial Surveillance program. If a carcass tests positive, it is condemned and the Canadian Food Inspection Agency will use the animal’s ID tag to trace that carcass back to its farm of origin, issue a violation letter and follow up with a visit to that farm.

More than a dozen drug residues are commonly found in light calves – about half are from scour pills and approximately one third come from antibiotics with very long withdrawal times.

Modern testing equipment is extremely sensitive and can detect residue levels of up to one billionth or even one trillionth of a gram of tissue or plasma. If you follow label directions and indications correctly, only one in 1,000 animals will have residues that exceed the allowable limits. When in doubt, contact your veterinarian.

Responsible shipping of any animals off the farm is critical to ensuring food safety and maintaining consumer trust and confidence in Canadian farmers and Canadian food.

As a dairy producer, here is what you can do to prevent antibiotic residues in your calves:

  • Prevention is better than treatment. To keep your calves healthy, feed the right amount of ration for a calf’s energy and protein requirements, keep them warm and dry, and ensure you’re providing extra feed in cold, wet weather.
  • Store any on-farm medications properly (e.g. refrigerate if needed, keep away from extreme heat or cold, properly dispose of expired medications etc.).
  • Follow label directions for dose, route, duration, frequency, injection site, treatment indication, animal species, use class, and withdrawal times.
  • Keep treatment records. Properly ID your animals and keep track of what medications are given to which calf. Under the Canadian Quality Milk program, all treated calves must be identified with a unique permanent identifier, like an ear tag. In group pens, mark treated calves with livestock markers to ensure they can be easily monitored for withdrawal times. Withdrawal dates can be tracked on a calendar, spreadsheet, pocket notebook or in herd management software.
  • Treat waste milk with caution. Feeding milk from treated cattle to calves could result in a positive residue test, so be careful.

Before shipping:

  • Check your treatment records.
  • Ensure you’re following the proper withdrawal times for each medication, including those you purchase from locations other than a vet, such as a feed supplier. If you have a veterinary prescription for an extra label use, follow the withdrawal times on the script as it may be longer than what is stated on the label. If you’re unsure about withdrawal times, including meat withdrawal times, contact your veterinarian.
  • Provide new owners with information about treatments and withdrawal times – this is a requirement under the Canadian Quality Milk program. For example, did you treat a calf for scours or use long-acting antibiotics for pneumonia?
  • Ensure calves are healthy before shipping. Shipping stress could result in a no-sale calf that could be euthanized at the sale barn.
  • Make sure all calves leaving the farm are properly identified, as per Canadian Cattle Identification Agency (CCIA), National Livestock Identification for Dairy (NLID) or Agri-Traçabilité Québec (ATQ) standards.

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