Milk residues

Question 1

What are the basic characteristics of veterinary medicines and growth promoters that pose public health risks?

Answer 1

Antibiotics: Can lead to residues causing allergies and antimicrobial resistance.

Hormones and Growth Promoters: May disrupt endocrine systems.

Anti-parasitic Agents: Risk of residues affecting human health.

NSAIDs: May contaminate milk/meat, causing unintended human exposure.

Question 2

Why do residues occur in animal products?

Answer 2

Failure to observe withdrawal periods.

Use of higher doses or longer treatment durations than authorized.

Illegal or unauthorized use of veterinary medicines.

Question 3

What is the Maximum Residue Limit (MRL)?

Answer 3

The maximum concentration of a residue legally allowed in food, ensuring consumer safety. It is expressed in µg/kg and considers the Acceptable Daily Intake (ADI) from all sources.

Question 4

What is the acceptable daily intake (ADI)?

Answer 4

The estimated daily amount of a substance, expressed per kg of body weight, that can be consumed over a lifetime without risk. It is based on NOAEL data divided by uncertainty factors.

Question 5

What is a withdrawal period and why is it important?

Answer 5

The withdrawal period is the time after the last medicine administration until residues in edible tissues drop below the MRL. It ensures food safety and consumer protection.

Question 6

What control measures are in place for veterinary substances?

Answer 6

National surveillance schemes to monitor residues.

Regulations requiring withdrawal periods.

Guidelines for proper medicine use and storage.

Testing bulk milk and meat for compliance.

Question 7

How is the use of antibiotics monitored in the veterinary sector?

Answer 7

Surveillance schemes testing animal products for antibiotic residues.

Tracking compliance with withdrawal periods.

Regular audits of medicine records.

Bulk tank milk testing to detect antibiotic contamination.

Question 8

Why is antibiotic residue in milk a concern?

Answer 8

Residues can disrupt dairy product fermentation (e.g., yoghurt, cheese).

Risk of allergic reactions in consumers.

Potential to foster antimicrobial resistance.

Question 9

What is the purpose of residues surveillance programs?

Answer 9

Monitor compliance with veterinary medicine regulations.

Identify and correct violations.

Build public confidence in food safety.

Question 10

What role does the veterinary medicines directorate (VMD) play in the uk?

Answer 10

The VMD oversees veterinary residues surveillance, ensures compliance with EU and UK regulations, and sets withdrawal periods.

Question 11

What factors influence the calculation of ADI & MRL?

Answer 11

Quantity of food consumed daily.

Substance metabolism in animals.

Potential residues from other sources (e.g., pesticides).

Question 12

What are off-label products in veterinary medicine?

Answer 12

Off-label products are medicines used in ways not specified in their Marketing Authorisation (MA), such as for a different species, condition, or dose, permitted under the Cascade to avoid animal suffering.

Question 13

What is the cascade principle in veterinary medicine?

Answer 13

The Cascade is a risk-based decision tree allowing vets to prescribe medicines under specific conditions when no suitable authorised product is available, prioritizing options in descending order of suitability.

Question 14

What are the steps of the cascade for prescribing medicines in GB?

Answer 14

In descending order of suitability:

1. Use an authorised veterinary medicine for the indicated species and condition.
2. Use an authorised veterinary medicine for a different species or condition.
3. Use an authorised human medicine or imported veterinary medicine under a Special Import Certificate.
4. Use an extemporaneous preparation (veterinary special).

Question 15

What is required from vets when using the cascade?

Answer 15

Obtain owner consent.

Keep accurate records.

Prescribe medicines responsibly, balancing benefits against risks (e.g., residues, resistance).

Set appropriate withdrawal periods for food-producing animals.

Ensure that the evidence base for your prescribing decisions is robust and complies with Recognised Veterinary Practice (RVP).

If the treatment does not comply with RVP it may require licensing by the Home Office as a regulated procedure under the Animal (Scientific Procedures) Act

Question 16

What are the statutory minimum withdrawal periods under the Cascade for food-producing animals?

Answer 16

Eggs and milk: 7 days.
Meat (poultry and mammals): 28 days.
Fish meat: 500-degree days. (temperature-based calculation used to determine withdrawal period)

Question 17

What factors must vets consider when setting withdrawal periods under the cascade?

Answer 17

Authorised withdrawal periods.

Pharmacokinetics of the medicine in the treated species.

Increased doses or longer treatment durations.

Ensuring no residues above the MRL remain.

Question 18

What is the role of the Veterinary Medicines Directorate (VMD) in regulating off-label use?

Answer 18

The VMD oversees compliance, maintains the Product Information Database, and ensures medicines used under the Cascade meet safety, quality, and efficacy standards.

Question 19

What are the main principles of responsible antibiotic prescribing in veterinary medicine?

Answer 19

Use narrow-spectrum antibiotics when effective.

Base prescriptions on culture and sensitivity data.

Minimise selection pressure by optimizing dose and duration.

Ensure good biosecurity, hygiene, and husbandry practices.

Question 20

Why should narrow-spectrum antibiotics be preferred over broad-spectrum antibiotics?

Answer 20

Narrow-spectrum antibiotics target specific bacteria, reducing the risk of promoting antimicrobial resistance compared to broad-spectrum antibiotics.

Question 21

What must be considered when prescribing human medicines under the Cascade?

Answer 21

Human medicines cannot be prescribed simply for cost reasons and must not be interchangeable with veterinary medicines unless justified by the Cascade.

Question 22

What is an extemporaneous preparation, and when can it be used?

Answer 22

An extemporaneous preparation is a veterinary special made without a Marketing Authorisation. It is used as a last resort under the Cascade when no other suitable option exists.

Question 23

Describe off-label use/cascade in horses

Answer 23

A horse declared as non-food producing in its passport can be treated as a non-food animal under the cascade.

A horse that has not been signed out of the food chain in its passport must be treated as a food-producing animal under the cascade.

Lists substances essential for the treatment of horses. These substances can be used in horses declared as food or non-food producing in the passport under the cascade using a statutory withdrawal period of 6 months.

Question 24

Who can dispense cascade medicines

Answer 24

Only vets registered with RCVS may prescribe medicines under cascade.

A Suitably Qualified Person (SQP) may supply authorised veterinary medicine that falls within scope of registration they hold, against prescription from vet for use under cascade.

A pharmacist may dispense authorised veterinary & human medicines, & extemporaneous preparations they have prepared, against prescription from vet for use under cascade

Question 25

What are the conditions when prescribing a product under the cascade in food producing animals

Answer 25

Pharmacologically active substances contained in medicine must have MRL, but not necessarily in species for which it is intended to be used

When checking this, also consider ‘other provisions’ listed with MRL, e.g., some substances not allowed for use in animals producing eggs or milk for human consumption

vet responsible for prescribing medicine must specify appropriate withdrawal period

vet responsible for prescribing medicine must keep specified records

Question 26

What are the considerations when prescribing a product under the cascade in bees for honey

Answer 26

As there is no minimum withdrawal period set for honey, you must set suitable withdrawal period that will ensure no risk to consumer health

Further guidance is available from National Bee Unit.

Question 27

Describe important medicines under the cascade

Answer 27

In order to legally import medicines for use under cascade you must apply for Special Import Certificate using Special Import Scheme

Failure to obtain certificate for imported medicine is offence under the Regulations

Question 28

Describe the use of extemporanous preparations under the cascade

Answer 28

Extemporaneous preparations (also known as “veterinary specials”) are products that don’t hold Marketing Authorisation (MA)

These products haven’t been assessed against same standards of quality, safety (for target animal, user, consumer & environment) & efficacy as authorised veterinary medicines

They can legally be prescribed, supplied & used under last step of cascade

Carry higher risk than authorised medicines & you should consider this when prescribing them.

Question 29

How do you calculate the concentration of antibiotic in milk from a bulk tank?

Answer 29

Question 30

Calculate the concentration of antibiotic in milk:

Answer 30

Question 31

If a farmer suspects antibiotic contamination in milk, what steps should they take?

Answer 31

Question 32

What would the concentration in the bulk tank indicate about antibiotic contamination?

Answer 32

Higher concentrations suggest closer timing to treatment.

If residues exceed expected withdrawal periods, there may be errors in treatment timing or sabotage.

Question 33

What would you investigate if a cow fails residue tests long after the withdrawal period?

Answer 33

Verify treatment dates and dosages.
Investigate for potential retreatment or additional exposure.
Consider testing other animals in the herd for contamination.

Question 34

How do you estimate theoretical concentration in milk for a given dose?

Answer 34

Question 35

Calculate the theoretical concentration in milk for this dose

Answer 35

Question 36

What is the Delvotest threshold for antibiotic residues in milk?

Answer 36

The typical threshold is 0.004 µg/ml, indicating the minimum detectable concentration for a pass result.