Proper drug use essential

The goal of animal health programs is to maximize the health and productivity of our livestock.

While veterinarians and livestock producers use management strategies and vaccination programs, pharmaceuticals are occasionally a necessary and important way to prevent and treat disease.

All products licensed for food animals in Canada have a drug identification number and specific label instructions, which include dosage, route of administration and withdrawal times. The withdrawal times ensure that meat from animals that have been treated with pharmaceutical products is safe for human consumption.

Producers who use animal health products need to closely follow label instructions to ensure they work correctly and that Canadian animal health and human safety standards are met.

Veterinarians may occasionally need to recommend the use of pharmaceutical products in an “off-label” manner. This may be in a dosage that is higher than recommended on the label or the use of a product that is not approved for a particular species.

Most veterinarians are careful about using products in an “extra-label” manner, but species such as sheep, goats, bison and elk may have little access to products that have label claims and approved dosages.

In these situations, it is still important to establish appropriate withdrawal times to prevent drug residues in meat.

Mistakes are occasionally made when administering pharmaceutical products, usually by accidentally giving the wrong dosage or product. As well, cattle are sometimes exposed to an environmental toxin that may pose a meat residue risk. Veterinarians must still provide producers in these situations with appropriate withdrawal times before slaughter to ensure food safety.

The Canadian Global Food Animal Residue Avoidance Databank (CgFARAD) is an important resource available to Canadian veterinarians.

The CgFARAD founding philosophy was that information about residue avoidance from all sources should be available from a scientific source.

The concept was initiated in the United States in 1982, but in 1998, 11 countries, including Canada, joined a multinational group to share data on food animal drugs and residue avoidance.

This global database includes information on more than 1,200 drugs and chemicals and information from more than 9,000 scientific studies.

The Canadian database is supported by two regional centres.

  • The Western College of Veterinary Medicine houses the western regional centre and is directed by Dr. Patricia Dowling.
  • The eastern regional centre is housed at the Ontario Veterinary College and is directed by Dr. Ron Johnson.

Dowling and Johnson are specialists in veterinary clinical pharmacology and are faculty members at their respective institutions.

CgFARAD personnel under the direction of Dowling and Johnson provide valuable assistance to veterinarians across Canada:

  • Veterinarians are able to contact CgFARAD when they need to prescribe drugs in an extra-label fashion.
  • CgFARAD personnel will use the global database to access the scientific information and provide veterinarians with scientific advice about appropriate withdrawal times.
  • CgFARAD can scientifically determine withdrawal times when animals are accidentally exposed to pesticides, heavy metals,and other chemicals.
  • They can assist feed mills and processors when accidental contamination of feed has the potential to create residues in food animals.

CgFARAD is a valuable resource for veterinarians and an important component of ensuring food safety for the Canadian public. It deals with 1,700 to 1,800 requests for advice and recommendations each year and continues to anticipate growth over the next few years.

The CgFARAD unit has often struggled for consistent and stable funding and has recently been supported by animal industry organizations, veterinary associations and pharmaceutical company funding.

It would be ideal if extra-label drug use never occurred or was unnecessary in food animals. Producers of all food animal species should be careful to follow veterinary instructions when administering pharmaceutical products. However, it is reassuring that veterinarians have a place to turn to get scientific advice on how to ensure that residues do not occur in food products when extra label drug use is necessary or when mistakes occur in administration.

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