Flock Health

Mike Joyce, D.V.M., Dip. Path, Diplomate, A.C.P.V.
Joyce Veterinary Services
R. R. #1
Hillsburgh, ON NOB 1Z0

FLOCK HEALTH can mean different things to different people. Flock health in the medical sense can mean the absence of disease (clinical or subclinical) in a flock. Or it can mean providing the optimum environment for maximizing profitability in the presence of or in spite of the presence of disease. To the animal rights advocate it may have a totally different meaning. Health to them may be applied in a broader sense. Taking layers out of cages and putting them on the ground may translate to some to be more "healthy"; yet, potential risk of exposure to other disease situations may be enhanced - i.e. parasitic or environment challenges.

In modern poultry production, we have created "diseases" in our quest for that perfect bird that will grow the biggest, in the shortest time, on the least feed and return the most profit!

Diseases such as heart attacks, ascites (RSHF - right sided heart failure) and the multitude of leg problems (VVD, slipped tendons, etc.) are what I term modern man diseases. These are conditions which we very often accept as "normal" provided we attain our economic profitability goals.

So what is Flock Health??? From our perspective, it most likely means maximizing (or optimizing) profitability by minimizing loses due
(1) to improper feed utilizations (i.e. FC),
(2) improper growth rates (gain, ADG)
(3) clinical disease (morbidity, mortality and culls)
(4) sub-clinical disease
(5) condemnation loses (farm related).

The following Flock Health Check list will highlight some areas which can impact on the ability to get the most return on our investment (ROI).

Bird Quality

This refers to genetic potential of the broiler, broiler breeder management (vaccination programs, feeding programs, sanitation programs, collection and transport procedures etc.). Unfortunately, in the Canadian system, the independent producer has little control over this factor in flock health. Very often we have little knowledge of what breeds ( more correctly strains) are used, number of broiler flocks supplying our broilers or ages of breeder flocks. These can have impacts on how we raise /feed or manage our birds.

Breeder flock and hatchery management are very critical to flock health. How they are hatched, when they are hatched, how they are handled, vaccinated and transported most often are unknown to the producer.

Points to remember:

1. You're paying for your chicks - don't be satisfied with poor quality.
2. Request breed and breeder flock information.
3. Keep good first week records.

Biosecurity

Biosecurity is a term referring to the management procedures used to attempt to keep disease off a farm or premises or keeping disease transmission from premise to premise to a minimum. It is a much talked about but little acted on concept. Some simple procedures can go a long way. Some basic points to remember:

Points to remember:

1. Keep doors locked.
2. Keep separate coveralls and boots in each barn.
3. If using disinfectant foot baths, change frequently i.e. every other day - absolute minimum.
4. Visit young birds first.

Nutrition

Nutrition can have impact on health in several ways. 1. - Proper nutrition for maintenance and growth 2.- Improper nutrition - with deficiencies causing chemical disease, common examples are biotin deficiency and Vit.E/Selenium deficiency or nutritional excesses causing toxicities (i.e - such as excessive levels of salt). If there has been a very sudden onset of problems - such as sudden increase in water consumption or sudden lack of appetite, feed related problems must be considered.

Indirect nutritional problems are more of a challenge. The more insidious problems such as lack of performance that are feed or nutrition related are much more difficult to detect. and diagnose. The more common problems affecting performance such as IBD (Infectious Bursal Disease), IBV (Infectious Bronchitis Virus) or coccidiosis should be ruled out first.

Points to Remember:

1. Keep retention samples on farm, well labelled, of all loads delivered to farm - always good to be able to compare to retention samples at the mill.
2. Visually examine food closely.
3. If you are paying for a type of ration (i.e. consistency especially), don't settle for less. Growth rate is related to consistency. Mash (fines) won't give you same growth rate as pellets.
4. Know what is in your feed both nutritionally and medicinally.

Sanitation

Disease (or lack of flock health) is very often a result of direct microbial challenge and load. Small numbers of organisms may be overcome by bird immunity. Very often disease it is only subclinical. In the poultry barn environment it is important to remember rarely is a bird faced with only one set of disease causing factors. There are usually many viruses attacking the birds immune system, a multitude of bacteria, many species of coccidia, probably some mold and probably some degree of insect and rodent challenge. All the while the bird is fighting for a place at the feed pan or water nipple. A bird in a chicken flock, in a poultry barn has a very stressful existence.

Anything we can do to reduce the level of any or all of the invading microbes will assist the bird in its fight to maintain a healthy status.

Points to remember:

1. "Elbow grease" is 95% of the battle - a good physical cleanout will help your disinfectant work even better.
2. Rotate class of compounds periodically i.e. every second crop rotate to a different class of compound to decrease resistance build up.
3. Consider following a good Cleaning (C) + Disinfection (D) with Fumigation (F) at least once per year and preferably 2x per year.
4. If you have multiple species and/or multi ages on premises consider C+D+F after every crop.

Medication Programs

Medication programs in feed and water can be utilized for preventing disease, treating disease or enhancing growth.

Points to remember - Feed MEDICATION.

1. Don't use medication programs as a crutch for less management efforts.
2. Coccidiostats/Growth Promotants - don't switch for the sake of switching ; switching from a program that is effective and profitable for the sake of switching can cost you money. Ideally monitor health status of G-I Tract - should be part of a systematic program.
3. Don't leave out coccidiostat medication in prestarter - will be problem long term.
4. Use appropriate drug levels for your needs.
5. Choices - coccidiostats.

   Best: Ionophore straight through.
   Next: Chemical/Ionophore shuttles.
   Least: Chemicals straight through. (Can be placed for chemical straight through - if used strategically).

II Points to Remember- Water medication.

1. Use correct drug, at correct time, at proper level - i.e. tetracycline - resistance has been a problem; sulfonamides- too high too long can cause toxicity; don't use under 2 weeks of age and for longer than four days.
2. There are excellent drugs (expensive) to use against E. coli but most need to be used on the recommendation and advice of a veterinarian (i.e. enrofloxacin, doxycline, apramycin).
3. Calculation of dosage and amounts is important for the best response to treatment - i.e. use correct water consumption guidelines for calculation.
4. Observe appropriate withdrawal times. If not sure - ask for guidance.
5. Do not overtreat - yeast infections - crop mycosis - can and do occur as a result of excessive and extended drug usage.

Management Programs:

(1) Ventilation

• is used to prevent disease by eliminating dust and microbes.
• optimum ventilation gives optimum growth.

Points to remember: ventilation critical even for the first five days - watch for draughts.

(2) Lighting Programs

• can be used to prevent disease (i.e. flips, legs, ascites) as well as optimizing growth. Remember baby birds need rest periods.

Points to remember: genetics and nutrition have caught up to the impact of restricted lighting programs. They still work but not like they did 10 years ago. Be prepared to modify programs to your needs.

(3) Litter - key to many disease situations:

x's damp litter

• bacterial growth
  • - higher E. coli challenge.
  • - more N.E.
• more foot problems - pododermatitis
• more leg problems - VVD, TD.
• more aspergillus problems
• more coccidiosis challenge - even subclinical coccidiosis will rob profits.
• more ammonia
• more respiratory disease as damaged lining helps viruses take hold.
• more breast blisters and buttons (turkeys especially).
• more breast blisters

x's dry - dust

• more respiratory problems.
• more eye problems.

Points to Remember:

1. Keep drinking devices at appropriate levels
2. Change nipples as required.
3. Adjust pressure for optimum usage.
4. Keep waterlines clean (Chlorine, H202)
5. PLT(Poultry Litter Treatment) - being evaluated and used more frequently (esp. Turkeys).
6. Remove wet litter as needed; top up litter as needed.
7. Rodent/Pest Control - reduces disease spread significantly, carry variety of viruses, bacteria.

MONITORING

The only way to make informed decisions about the success or lack of success of any program is evaluating performance via monitoring and analysis programs.

The broiler industry in Canada has always relied on a fire fighting approach. Wait for a problem to occur - be it clinical disease, poor performance or a reduction in profitability and submit birds to a diagnostic lab (private or government) - hope for a clear cut diagnosis, treat and make changes. What I call the reactive approach.

In my practice I have been able to provide a PROACTIVE approach. Due to a system of contracts, I have had the opportunity to put in place what I call a Flock Health Monitoring Program. Producer pays for diagnostic tests, condemnations and performance analysis and a third party pays for the on-farm time.

THE BASIC PROGRAM IS AS FOLLOWS:

1. Initial Condemnations Analysis and Report:

• - disease status or trends.
• - management changes recommendations.
• - vaccine program
• - medication (feed/water) recommendations.

2. Flock Health Check (FHC):
(i) first week - establish bird quality (necropsy + clinical evaluation).

• - evaluate brooder management.
• - assess mortality patterns
• - assess barn dynamics
• - identify stressors
• - Make recommendations:
  • Vaccine
  • Medication need.
  • Nutrition supplementation
  • Managerial.

(ii) Day 28-35

• - Clinical evaluation of flock.
• - Barn environment assessment.
• - Necropsies.
• - Additional diagnostics as required.
• - Recommendations - as above.

(iii) At processing

• - serology - at or near processing.
• - plant visit - if required.

3. Condemnations analysis.

4. Performance analysis.

5. Complete program with report and recommendations.

Ongoing program:

1. Serology at processing.
2. Performance + Condemns Analysis.
3. Full work up once per year or as required.

SUMMARY: The broiler chicken is essentially a "baby". The first 10-14 days of life is the critical time for flock health because:
(a) modern broiler has tremendous relative growth rates.
(b) is very sensitive to its environment.
(c) anything which effects growth or "health" cannot be made up in a 38-42 day period.