Drug Residues

Best Practice: Responsible Drug Use

1. The dairy should have a documented Veterinary-Client-Patient Relationship (VCPR).

(download Best Practice: Responsible Drug Use)

The Veterinary-Client-Patient Relationship states that the veterinarian on record takes responsibility for making clinical judgements regarding the health of animals on the farm and the need for medical treatment. Additionally, the producer agrees to follow the veterinarian’s instructions regarding treatment. An ideal VCPR should be written, signed and dated by both the producer and their veterinarian. If multiple veterinarians are used for different areas of management, a separate VCPR should delineate the role of each veterinarian on file. All parties should review and sign an agreement yearly.


VCPR Forms


2. Drug use for commonly treated diseases should be detailed in written treatment protocols.

Treatment protocols support consistent drug administration practices and allow for better evaluation of treatment efficacy. Protocols should be written, accessible to those performing treatments, and reviewed yearly by management and the herd veterinarian.


3. Specific personnel who are authorized to perform treatments should be trained in protocol use and proper drug administration techniques.

All employees who perform treatments should receive training on utilizing treatment protocols, proper drug administration (including intramammary tubes), and treatment record keeping. Training should be reviewed yearly and documented in an employee file.


Additional Resources

See also the Additional Resources under Residue Avoidance.



BQA Injection Site Demonstration

Excede Base of Ear Injection Demonstration

Best Practice: Drug Residue Avoidance

1. All animals should have individual, permanent ID. Animals treated with a medication which requires a milk withhold should be identified in a highly visible fashion and segregated during milking.

Reliable and visible permanent identification is important for record-keeping and should be placed soon after birth. Additional highly-visible ID methods, such as paint or leg bands, allow easy identification of cows under milk withhold for workers in pens and in the parlor. Where possible, cows under milk withhold should be milked separately from the rest of the herd to minimize the risk of accidental contamination of the bulk tank.

2. Cows treated with an intramammary antibiotic at dry-off should be clearly identified and segregated during the dry period. Consider testing for antibiotic residues after freshening and before returning to the milking herd.

Dry cow treatments are a residue risk if they enter the bulk tank. A combination of highly visible identifiers and physical barriers should be used to separate dry cows from the milking herd. Scrupulous record-keeping, residue testing, or both should be employed prior to adding fresh cows to the milking string to ensure that both the minimum dry period length and milk withdrawal period has passed.


Work with your veterinarian and milk processor representative to determine which on-farm drug residue test is appropriate for your dairy. More information on these tests can be found in the NMPF Milk and Dairy Beef Drug Residue Prevention manual.

3. Drug use should follow written treatment protocols and be recorded in a timely manner.

Treatment protocols support consistent drug administration practices and allow for better evaluation of treatment efficacy. Treatments can be recorded on paper or in a computerized system, and should be retained for at least 2 years. Computerized systems allow for easier evaluation of treatment efficacy.


See Responsible Drug Use for treatment protocol templates.


4. Drugs should be used following the manufacturer's label instructions, or following the instructions provided by a veterinarian.

Drug withdrawal periods are only accurate when label instructions are followed, including amount used (dose), route of administration, injection location, and any other specific instructions. A veterinarian who prescribes a drug used in a different manner (called Extra-label Drug Use, or ELDU) should provide instructions for use and an appropriate withdrawal period for meat and milk.


5. Drugs should be stored to limit access by unauthorized persons, and to limit accidental administration of an incorrect product.

Storing drugs for non-lactating cattle in a separate or locked location minimizes accidental administration in the milking herd. Only keeping drugs that are used in an active treatment protocol, and removing from the premises all drugs that are not labeled for use in dairy cattle can also limit accidental drug residues.

6. Develop a standardized set of practices that occur before a cow is marketed for sale.

A written checklist or protocol reminds individuals to perform basic tasks each time before marketing a cow for processing. These should include verifying a cow’s fitness for transport (milking, hydration, lameness, BCS), ensuring no drug residue withholds are in effect, and transportation considerations.


Additional Resources for Residue Avoidance

The following manuals have many excellent resources for drug residue avoidance.


NMPF Milk and Dairy Beef Drug Residue Prevention: 

♦ ELDU decision algorithm (p.16) 

♦ Prohibited drugs for food animals (p.17)

♦ Drug-specific risk factors for residues (p.21)



Dairy Animal Care Quality Assurance:

♦ Economic value of market cows and bulls (p.20-22)

♦ Injection site lesions (p.30-32)

♦ Marketing/cull checklist and log (p.81)