How to ensure that animal products are safe

If well used, veterinary drugs can prompt economic development, food safety/security and animal welfare status. However, if malpractices take place, the said drugs can cause untold suffering to the economy, consumers and animals’ well-being. One such malpractice is failure to observe the veterinary drug withdrawal period.

This is the period between the last drug administration to an animal and the time when the animal/animal’s products are considered safe for human consumption in that they are free of drugs/drug residues or contain maximum residue limits (MRLs).

The withdrawal period range between a few hours to as many as 28 days depending on the drug used. This implies that seemingly good products like milk, meat, honey, eggs and fish can be contaminated with the said drugs.

A past study carried out in Kenya showed that only 17 per cent of the sampled livestock producers observed the recommended withdrawal periods.

The challenge therefore is on how to reduce losses necessitated by withdrawal requirement.

Veterinary drugs

Veterinary drugs are used in production enhancement; feed conversion rate enhancement and disease control/treatment in food animals among other animals.

These drugs include growth promoters, antimicrobials, coccidiostats, dewormers, ticks and other external parasites control agents, hormones and others.

The drugs are administered through drenches such as dewormers; sprays such as acaricides; in feeds such as coccidiostats; in water; through body openings like the eyes, ears, uterus, anus ,teats and so on.

After administration, some of the drugs are absorbed from the administration site to the bloodstream and they circulate to the body organs like the kidney and the diaphragm muscle from where samples can be taken for confirmation of the drugs/drug residues’ presence.

Implications of drug residues in animal

Antimicrobial resistance: Animals and humans use the same drugs to counteract micro-organisms such as bacteria. These include tetracycline, penicillin, sulphonamides and others.

When humans consume sub-lethal doses of these drugs in form of residues, the micro-organisms develop resistance with time, thus when humans get sick and are treated with the said drugs, the drugs are ineffective. Anti-microbial resistance is a universal issue and if it goes on unchecked, the doctors might run short of drugs to treat simple ailments.

Hypersensitivity: Some people are allergic to some antimicrobials such as penicillin. When these people accidentally consume the allergens as residues in animal products, allergic reactions some of which are fatal take place.

Interference with normal intestinal micro flora: There are good bacteria that live in a person’s body. Prolonged consumption of drug residues might kill the friendly bacteria, opening a window for lethal micro-organisms such as fungi to infect the individual.

Toxicity/Cancer: Some pesticides such as DDT and Lindane that have been used to control ticks and other parasites have long been associated with cancer and thus banned in some countries.

Chemical effects: Some drugs like the hormones used to induce abortion in animals have the same effect in humans.

Environmental pollution: Presence of orally administered drugs lead to shedding of the drugs into the environment through faeces. These drugs can be consumed by others animals especially grazers and this can be a cause of anti-microbial resistance in animals.

How to economically implement the withdrawal period.

Disease control: If diseases are controlled, there is minimal use of drugs used to treat them. Disease control methods such as vaccination against bacterial diseases like fowl Typhoid in Chicken and Anthrax in farm animals will thus be carried out once unlike the antimicrobials used to treat the same and whose dosage is given for a long period. Vaccination against viral diseases is also important as antimicrobials are also administered in treatment of viral diseases as a way of keeping off the bacteria.

 Hygiene in farm animals is a disease control measure of many diseases such as mastitis, Coccidiosis and diarrhoea. Use of professionals is also important.

Short acting drugs: There are short acting and long acting preparations of drugs such as penicillin and tetracycline. The short acting preparations should be used for animals which are or their products are likely to be consumed soon.

Improved nutrition and other good animal practices: Healthy animals are less likely to get sick while practices that minimize disease incidents like dehorning and hoof trimming also contribute to an animal’s health

Housing: proper houses for specific animal types contribute to their well-being thus poultry houses that keep the birds warm especially at night lower incidences of pneumonia.

Breeds/breeding: Some breeds of the same species are more vulnerable to disease. Layers and broilers are more prone to diseases such as Gumboro as compared to indigenous chicken. If one is not in a position to implement strict disease control, then raring animals that are specific disease resistant will reduce disease incidences and hence use of drugs.

How the consumer can avoid drug residues

The danger with drug residues is that their presence is not visually detected. Further there are few laboratories that test for the same and when they do, they charge exorbitant fees.

However, one can minimise the chances by purchasing animal products from reputable sources; purchasing pooled products such as milk that is delivered to a cooperative society as dilution of said milk from treated animals takes place to MRLs; ensuring that products meet required standards such as meat inspection as research has shown that levels of some drugs such as tetracycline drop significantly through evaporation during cooking.

Role of the regulatory agent

 The Veterinary medicines directorate (VMD) is the agent that oversees manufacturing, importation, exportation, registration, distribution, prescription and dispensing of Veterinary drugs, while Kenya Bureau of standards (KEBs) has at least 9 standards that guide on veterinary drug residues and antimicrobial resistance in food.

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