Ask the Vet
Ask the Vet: A year of change
By Tom Inglis
What does the change in the use of medically important antimicrobials in poultry production mean to producers?
By Tom Inglis
Antibiotic resistance is real. In Canada and around the world, fewer antimicrobials remain effective in controlling infection as more microbes become resistant in both human and veterinary medicine.
In its 2015 report on nationwide antibiotic use and drug resistance rates, Health Canada stated that ‘Superbugs’ (bacteria with multi-drug resistance) have already cost Canada one billion dollars in medical care. The report noted a 14-fold increase in the use of last-resort antibiotics to treat difficult infections since 2002. Already, more than 18,000 patients in Canada acquire multi-drug resistance strains of bacteria each year. In the E.U. and U.S., hospital acquired infections kill a total of 50,000 people each year. The World Health Organization has called it a global emergency.
Due to the complex nature of antimicrobial resistance, its multi-factorial and concern to human and animal health, many players globally and in Canada (including poultry producers and their veterinarians) are acting to stop and if possible reverse the danger of antimicrobial resistance.
The Government of Canada has introduced Antimicrobial Resistance and Use in Canada: A Federal Framework for Action. The focus is on surveillance, stewardship and innovation. Additionally, Health Canada has introduced and will implement new policies and regulations. The use of Medically Important Antibiotics (MIAs) for growth promotion (rate of gain, feed efficiency) has been eliminated. As of December 2018, MIAs currently available over-the-counter will be rescheduled as prescription and will require a valid prescription before they can be dispensed. Only pharmacists and veterinarians can dispense non-feed use MIAs, water soluble medications for examples. Feed manufacturers can sell feed containing MIAs pursuant to a prescription. Prescriptions can only be written within the confines of a valid Veterinarian-Client-Patient-Relationship (VCPR).
Many countries have already taken action. Here, the Canadian Veterinary Medical Association has introduced Veterinary Oversight of Antimicrobial Use-A Pan-Canadian Framework for Professional Standards for Veterinarians. Veterinarians are best positioned to assess the benefits and risks of antimicrobial use in poultry and must explain to their clients the importance of judicious use of antimicrobials. Namely, the right drug for the right bug at the right dosage for the appropriate time interval.
MIAs will only be used in poultry operations under veterinary oversight and pursuant to a prescription generated by a veterinarian, who has established medical need and appropriateness within the confines of a valid VCPR. In addition to their role in antimicrobial stewardship, bird welfare is paramount and birds that are deemed responsive to treatment must be treated.
Prevention and treatment
Globally, there are two trends in the use of MIAs in animal production, namely the use of antibiotics for treatment but not for the prevention of disease. The World Health Organization on Nov. 7, 2017, released the press release, Stop giving antibiotics to healthy animals. The World Health Organization is recommending that livestock and poultry producers stop using antibiotics to promote growth and prevent disease in healthy animals. This opens up the conversation of what is meant by prevention and treatment?
1. Prevention is described as the use of a MIAs in healthy birds to prevent the occurrence of a disease caused by bacteria. For example, an antibiotic is used because there is risk of disease.
2. Treatment is detailed as the use of a MIAs to treat a clinical or subclinical disease (metaphylaxis/control) in poultry, including the mass medication of flocks in which a subset of birds are identified with a clinical or subclinical disease that will respond to administration of a specific antibiotic.
Where possible, without sacrificing bird welfare, use an MIAs for treatment that is categorized by Health Canada as medium importance (Category III) rather than one that is high importance (Category II) or very high importance (Category I). It is important to use the right antibiotic for the disease at hand rather than necessarily one of less importance but has limited efficacy and could promote the development of antimicrobial resistance. Health Canada’s categorization is based on the options available to treat disease in human medicine. There are very few drugs in Category I and if resistance would develop to these antibiotics, there could be no other options available for patients with particular diseases.
3. Examples of Category I, II, and III used in poultry production:
- Category I: Third and fourth generation cephalosporins and fluoroquinolones
- Category II: Tylosin, lincomycin, gentamicin, neomycin, virginiamycin
- Category III: Bacitracin, tetracyclines and sulphonamides
- Category IV: This category is deemed low importance by Health Canada because these drugs do not have a counterpart in human medicine. Examples: ionophore anticoccidials (antibiotics but not MIAs); non-ionophore anticoccidials (not antibiotics); and bambermycins.
Poultry producers have led with the following strategies:
- Eliminated the preventive use of Category I in commercial chickens and turkeys and breeders by May 2014.
- Withdrew the preventive use of Category I in parent stock by May 2015.
- The Canadian Hatchery Federation developed a turkey hatchery-specific AMU reduction strategy to eliminate the preventive use of Category II antibiotics by October 1, 2017.
- Chicken Farmers of Canada (CFC) have embarked on an antimicrobial use reduction strategy to eliminate the preventive use of Category II MIAs by the end of 2018, and pending reassessment, elimination of Category III MIAs for preventive use by the end of 2020.
- Turkey Farmers of Canada (TFC) also have an antimicrobial use reduction strategy to eliminate the preventive use of Category II antibiotics by the end of 2018 and the preventive use of category III antibiotics by the end of 2019.
Note: the AMU strategies of CFC and TFC are not raised without antibiotics programs, considering ionophores and non-ionophores (chemical) anticoccidials can be used. Additionally, MIAs can be used for therapeutic purposes to maintain the health and welfare of birds.
How will results of the MIA-use reduction strategies be measured?
A mandatory requirement to not preventively use Category II and III (depending on timeframe) will be included in On-Farm Food Safety Programs and audited. Additionally, surveillance will be performed through poultry industry use surveys, as well as government surveys via the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) of the Public Health Agency of Canada.
What does the elimination of the use of Category II and III for prevention mean for my birds?
As far as treatment is concerned, there will be no change, as all MIAs are still available for treatment. Birds with treatable bacterial infections will be treated according to the strategies of CFC and TFC. With regards to no longer using antibiotics for prevention, this includes not using drugs such as virginiamycin and bacitracin. Both these antibiotics have been used for over 20 years to prevent Necrotic enteritis and have considerable benefits that contribute to better feed utilization, and litter management. When these products are not used in a preventative manner the producer must control coccidiosis and avoid immune-suppression.
This checklist may be of value. All points are important and inter-connected:
- Flock-to-flock biosecurity: Correct use of cleaners, disinfectants and pest control products.
- Water quality: Remove biofilms and manage sulphates and sodium levels.
- Manage coccidiosis: Coccidiosis predisposes to necrotic enteritis, which can lead to wet litter conditions predisposing the flock to higher ammonia and increased risk of E. coli infections.
- Prevent immunosuppression: Monitoring and evaluation of vaccination programs and procedures.
- Litter management: Attention to pen temperature, ventilation rate and drinker management.
- Early detection of disease: Watch for changes in water intake, litter condition and bird behavior.
- Alternative products in grow-out: Evaluate products to learn how to use them so birds can handle challenges.
- Monitor antimicrobial sensitivity and use: We can’t manage what we can’t measure.
- Enhance the Veterinarian-Client-Patient-Relationship: A renewed opportunity to work together.
- Communication: Network, provide feedback and share observations.
Tom Inglis is managing partner and founder of Poultry Health Services, which provides diagnostic and flock health consulting for producers and allied industry. Please send questions for the Ask the Vet column to email@example.com.