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U.S. Department of Health and Human Services

Animal & Veterinary

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Animal Husbandry and Disease Control: Poultry

Animal Husbandry and Disease Treatment/Control in Poultry

Meeting on the Use of Antimicrobial Drugs in Food Animals and the Establishment of Regulatory Thresholds on Antimicrobial Resistance

Dennis P. Wages, DVM. Dipl. ACPV
College of Veterinary Medicine
North Carolina State University
Raleigh, North Carolina

January 22, 2001


General considerations

  • Three industries:
    • Broilers
    • Turkeys
    • Layers
  • Meat production in broilers and turkeys will be discussed primarily


Disease prevention management

  • Vertical Integration (VI) plays a vital role in disease prevention
    • Company controls housing, breeds and breeders, feed, live production, live-haul, and processing
    • Contract growers and company owned farms
    • Over 95+% production in broilers (VI)
    • Over 85% of the production in turkeys (VI)


Production parameters

  • Broilers:
    • 45 to 56 days of age weighing 5 – 7 pounds
      • Straight run; sexes raised separately
    • Feed conversion 1.90 – 2.10 pounds of feed per pound of gain
    • Livability 95%
    • Condemnations < 1%
    • Cost per pound of production 20-25 cents

      • Add processing cost per pound
    • Two-thirds of cost in feed


Production parameters

  • Turkey hens:

    • 14 – 16 weeks of age weighing 15 – 18 pounds
    • Feed conversion: 2.20 pounds of feed per pound of gain
    • Livability: 94%
    • Condemnations less than 1.5%
    • Cost per pound of production 32 cents per pound

      • Add processing cost per pound


Production parameters

  • Turkey toms:

    • 16 – 22 weeks weighing 32 – 45 pounds
    • Feed conversion: 2.6 pounds of feed per pound of gain
    • Livability 90%
    • Condemnations less than 2%
    • Cost per pound of production 35 cents per pound

      • Add processing cost per pound


Disease Prevention Management

  • Housing:
    • Environmental control houses; temperature and ventilation control (power ventilation)
      • Curtain sided houses
    • Closed water system in broilers (nipple drinkers)
  • All-in-all-out production results in same age of flock on farms
    • Broilers – 100%
    • Broilers chicks all placed on a farm at same time (within days)
    • Broilers all processed at the same time (within days)
    • Zone raising in geographic areas


Disease Prevention Management

  • Two Stage production in turkeys
    • Brooder house placement of poults
      • Cleaned and disinfected after each flock
    • Moved to grow-out facilities on same farm at approximately 5 weeks of age
    • There are single stage farms (brooder versus grow-out)


Disease Prevention Management

  • Biosecurity
    • Traffic control to and from farm
    • Wild bird and rodent control
    • Protective clothing (coveralls, boots, head coverings)
    • Dead bird disposal
    • Farm isolation
    • Farm clean-out and disinfection, down time
  • Best management practices/guidelines


Disease prevention management

  • Vaccination
    • Breeders: 10 – 12 diseases (22 - 25 serotypes) in chickens: 8 – 10 diseases (18 – 20 serotypes) in turkeys

      • Breeder health
      • Egg production
      • Maternal antibodies to chicks/poults
    • Blood testing standard for disease monitoring


PPT Slide

  • Meat birds: 5 diseases (10 serotypes) in chickens: 1-3 diseases in turkeys

    • Health
    • Production
    • Processing health
  • Blood testing standard for disease monitoring
  • Problems are not in diseases we can vaccinate for!


Antimicrobial Use

  • Therapeutic
  • Disease prevention/growth promotion
  • Day old injection/ In-ovo administration


Therapeutic Antimicrobial Use

  • E.coli infection is the #1 cause for use of therapeutic antimicrobials

    • Clostridia spp. and pasteurellosis are also treated
  • Secondary bacterial infection is due to primary respiratory and/or enteric disease

    • E. coli is troublesome; Does not lend itself to vaccine development; E. coli is ubiquitous
    • Infectious bronchitis as example of primary infection
  • E. coli primarily treated via water
  • Feed grade therapeutic antibiotics uncommon


Therapeutic antimicrobial use

  • We currently have 12 antibiotics used as intervention strategies for bacterial disease
  • Most commonly used
    • Tetracyclines, streptomycin, neomycin, bacitracin,
  • Less commonly used

    • Lincomycin, spectinomycin, tylosin, erythromycin, sulfonamides, penicillin
  • Fluoroquinolone are held in reserve because:

    • Importance to poultry and humans
    • Cost
    • Currently represents the only consistent treatment for E. coli


Therapeutic antimicrobial use

  • Guidelines established by AAAP/AVMA are used in the decision making process
  • Diagnostic work-up initiates intervention strategies
  • Management and supportive therapy considered prior to antimicrobial therapy


Therapeutic antimicrobial use

  • Antimicrobial use based on diagnostics, mortality and morbidity, age of flock, farm history, susceptibility patterns
  • Antimicrobials use must be approved by veterinarian, live production specialist, or other health service technician before use
    • Extra-label and fluoroquinolone use ordered and prescribed by veterinarian


Therapeutic antimicrobial use

  • Records kept and utilized
  • Most important to therapeutic antimicrobial use are the diagnostics performed to identify the primary agent involved to initiate preventative strategies and avoid future therapeutic interventions
  • Currently no vaccine or antimicrobial for improper management


Disease prevention

  • 4 antimicrobials are used for the prevention of clostridial (necrotic) enteritis
  • “Sub therapeutic” vs. low level prophylaxis
    • Levels are lower than that used in an acute outbreak of disease
    • Anticoccidial feed additives are generally static and not cidal; proliferation of low numbers of coccidia predisposes the intestines to infection
    • Virginiamycin, bacitracin, lincomycin, tylosin, bambermycin*
  • Other antimicrobials used in therapy are not used for growth promotion


Mechanisms of action for low level antimicrobial use

  • Some are known and some unknown
  • Virginiamycin*, bacitracin*, lincomycin*, tylosin, bambermycin (chickens vs. turkeys)
    • Not tetracycline, erythromycin, penicillin, sulfonamides
  • Necrotic enteritis control
  • Increased hot and chilled carcass weights
  • Increased breast meat yield
  • Protein sparing effects


Antimicrobial use benefits

  • Maintains intestine tensile strength and integrity
    • Very important at processing (automation)
  • Reduces feed needed for a pound of gain

    • Reducing feed conversion from 2.00 to 1.99 represents 40,000,000 pounds of feed (chickens only) (89 million pounds – turkeys)
    • Reduces utility costs, and less contamination to the environment with nitrogen and phosphorus


Day-old injection – In-ovo

  • We deal with a biologic environment impossible to sterilize ……….. However ………..
  • Hatcheries have stringent disinfection and sanitation programs including microbiologic monitoring for fungi and bacteria (sanitation of eggs??)
  • In the incubation period, the yolk is drawn into the abdominal cavity at 19 and 25 days of incubation for chicks and poults respectively


Day-old injection – In-ovo

  • The egg is a closed system and the potential for small numbers of bacteria to rapidly increase in numbers because of the incubation temperature
  • The in-ovo system provided a unique opportunity to prevent bacterial proliferation in the yolk within the egg
  • Gentamicin and ceftiofur are most commonly used
  • Sarafloxacin is the only approved In-ovo antimicrobial and IS NOT and HAS NEVER USED


Other Considerations

  • Competitive exclusion products
  • Volumetric versus mg/kg dosing (AMDUCA)
  • Processing (antibacterial rinses); irradiation
  • Antimicrobial therapeutic use is a salvage procedure
  • No Vaccine for bad management and no drug for it either
  • Industry continuously evaluates what it does



  • Disease prevention is emphasized
  • Antimicrobial intervention is one tool used in an overall disease prevention/control program
  • The AAAP Therapeutic Antimicrobial Use Guidelines are supported by the poultry industry
  • National Turkey Federation and National Chicken Council support judicious antimicrobial use



  • Our therapeutic arsenal is small but what we have we need
  • Penicillin, tetracyclines, erythromycin, sulfonamides, ARE NOT USED AS GROWTH PROMOTANTS or as disease prevention
  • Bad management is NOT prevented by vaccination nor is it treated with antimicrobials