Obeying drug withdrawal periods become costlier for the farmers. For example, if your egg layers or cows get sick, and you have no other option than to give them an antibiotic with a seven-day withdrawal period.
By Dr Abdus Sabur Sheikh
Antibiotics are extensively used as growth promoters in livestock and poultry sectors to control diseases, facilitated feed conversion ratio, and for treatment purposes. As a result, antibiotic resistant bacteria are emerging, threatening to cause serious health hazards. Previous studies also reported that veterinary antibiotics are used vastly in livestock and poultry birds to control disease, enhance growth, promote health, and feed conversion efficiency, as well as to reduce animal susceptibility to stress-related diseases. Several antibiotics are extensively used in food animals for these purposes. These include tetracycline, sulfonamides, fluoroquinolones, macrolides, lincosamides, aminoglycosides, beta-lactams and cephalosporin, to name a few.
Antibiotics accumulate and form residues at varying concentrations in the tissues and organs of food animals. After using an antibiotic in the human or animal body, it kills bacteria, and the antibiotic is broken down in the body until it becomes a non-functional agent, and finally, it is eliminated from the body.
Withdrawal Period
Withdrawal periods (clearance or depletion time) of different antibiotics vary from one or two days to a couple of weeks. For instance, the minimum withdrawal period for Oxytetracycline and amoxicillin is three days, and for ciprofloxacin it is six days. In addition, previous studies shown that withdrawal period may vary between different antibiotics.
The withdrawal period defines the length of time required for an animal to metabolize the administered antibiotics under normal conditions and, also the time needed for the antibiotic concentration in the tissues to reduce to a safe and acceptable level described as tolerance.
The use of animal medicines is strictly controlled by Indian law and requires observance and adherence of the withdrawal period. The withdrawal periods have been calculated using rigorous scientific processes so that veterinary medicines can be authorised and administered to food producing animals, while at the same time consumer safety is protected.
Every medicine administered to animals, including antibiotics, has a withdrawal period. Farmers must follow these withdrawal times to be sure no antibiotics are in our food.
Following withdrawal periods means there is no traces of antibiotics in the meat or milk consumers buy for consumption. It implies that consumers are not exposed to unnecessary antibiotics. It means that farmers are doing everything they can to prevent the development of antibiotic resistance (ABR).
The purpose of the withdrawal periods is to ensure that foods do not contain residues of pharmacologically active substances above a maximum residue limit.
Public Health Hazards
Antibiotic residues can lead to allergy, cancer, antibiotic resistance, and other health effects. Residual penicillin in animal products can cause allergic reaction in some people. Other antibiotic residues like tetracycline, sulphonamides and aminoglycosides can also cause allergic reactions.
One of the most important concerns is antibiotic resistance. Animal products containing antibiotic residues can cause antibiotic resistance in man. The resistant bacteria can then cause diseases in man and such diseases are difficult and expensive to treat.
Antibiotic Residues and Their Consequences in Humans and Animals
| Antibiotic residues | Consequences in Humans/Animals |
| Tetracyclines | Primary and permanent teeth discolouration in children and infants, allergic reactions, and teratogenicity during the first trimester of pregnancy, nephrotoxicity, carcinogenic, hepatoxicity, and disturbance of the normal microflora of the intestines. It equally causes skin hyperpigmentation of areas exposed to the sun, proximal and distal renal tubular acidosis, hypersensitivity reactions. |
| Oxytetracyclines | Carcinogenicity and cytotoxicity in bone marrow of broiler chickens |
| Sulfadimidine | Carcinogenicity and allergic reactions. |
| Sulfamethoxazole | |
| Sulphamethazine | |
| Enrofloxacin | Allergic hypersensitivity reactions or toxic effects, phototoxic skin reactions, chondrotoxic), and tendon rupture. |
| Chloramphenicol | Bone marrow toxicity, optic neuropathy, brain abscess |
| Penicillin | Allergy, affect starter cultures to produce fermented milk product |
| Quinolones | Allergic hypersensitivity reactions or toxic effects (phototoxic skin reactions, chondrotoxic) and tendon rupture. |
| Amoxicillin | Carcinogenic, teratogenic, and mutagenic effects. |
| Penicillin G | Allergy (hypersensitivity reaction) ranging from mild skin rash to life-threatening anaphylaxis. |
Challenges and Strategies
Obeying drug withdrawal periods become costlier for the farmers. For example, if your egg layers or cows get sick, and you have no other option than to give them an antibiotic with a seven-day withdrawal period. This means that all the eggs or milk produced throughout these seven days will be thrown away. Many farmers therefore in developing countries find it difficult to obey withdrawal periods.
The cost resulting from obeying withdrawal periods can be minimized by following good management practices. This entails adopting production techniques that help to maximize efficiency and eliminate or reduce infections. It includes proper housing, putting farm biosecurity measure in place, good nutrition, proper vaccination, etc.
Herbs and probiotics can help prevent diseases in animals. Various research on herbs and plant extracts show that they can be used to prevent and treat diseases in animals. With herbs and probiotics, there are no withdrawal periods unlike antibiotics.
The veterinary professionals can play a vital role by making the livestock farmers aware about the importance of withdrawal period. Creating awareness is one of the best strategies that may positively reduce the risk of antimicrobial drugs residues in animal products.
Herbs, probiotics
In India, laws may exist about antibiotic withdrawal period, but steps are not usually taken to enforce them. As a result, many farmers don’t observe withdrawal periods. Antibiotic and pesticide residues are among the reasons why the countries like India are denied access into American and Europe livestock market.
Despite the cost associated with obeying antibiotic withdrawal period, it is still necessary that farmers adhere to it. If not, it can jeopardize the health of consumers. The best way to avoid the cost is by following best management practices that prevent or minimize infections Herbs and probiotics can help as alternatives to antibiotics. In India, drugs rules and regulations are controlled by Central Drugs Standard Control Organization (CDSCO). There is need of enforcing strict regulation regarding withdrawal period on farm animals by CDSCO.
Dr Abdus Sabur Sheikh, Sr. Program Manager–Livestock Technology and One Health at Passing Gifts (a wholly owned subsidiary of Heifer International) is a development professional having more 20 years of experiences in livestock-based livelihoods and animal welfare.
