Broilers and turkeys Flashcards
Growth rate of broilers
45g chick becomes 1900g at 34 days
Mortality rates of broilers
3% (gone up with decreased use of antibiotics)
Feed conversion rate of broilers
<1.55kg feed to 1kg meat
Related to the density of the feed as well as the health and growth rate of the bird
Higher density feed is more expensive
Water conversion of broilers
2x feed consumption
Management of broilers
Ventilation
§ Minimum ventilation rates
§ CO2, NH3
Temperature
§ Profiles standard for breeds, need to know these really well
§ Standards need tweaking depending on management and type of housing etc.
Humidity
§ Manage the litter
§ Biggest challenge is removing water from houses
Accreditation systems of broilers
○ Assured Chicken Production (Red Tractor) - about 80% of chickens in the UK, 38kg per sq meter
○ Freedom Foods (RSPCA)
○ Organic production
○ Better Chicken commitment
Intensive housing of broilers
○ Wooden or steel framed
○ Wood or steel cladding
○ Well insulated
○ Most have concrete floors, for better cleaning and disinfecting
○ Ventilation fans in the roof ridge or side of house. Getting the airflow right can be challenging
○ Windowed
○ Heating gas, oil, or biomass heating systems: direct or indirect (dont create CO2 and water in the house so very helpful for humidity management)
○ Drinker systems mostly nipple based
○ Feeder systems - either pan or track
○ Litter removed and disposed of after each crop
○ Colony sizes vary from 15-60k birds
○ Crop length anywhere from 30-56 days with 7-14 days down time between crops
○ Fast, high turnover - 6-7 batches a year
Extensive housing of broilers (free-range)
○ Often intensive housing that has been modified
○ Development of basic wooden or steel ‘Arks’
○ May or may not be heated
○ Drinker systems often bell designed
○ Feeder systems often auger fed cans
○ May be intensive housing used at lower stocking density with natural light available
○ Free range needs to spend at least half of its life outdoors
○ Birds reared in controlled environment housing until 21-28 days old
○ Colony sizes generally smaller, 2-20k birds
○ Generally multi-aged systems
○ Down time very variable, sometimes continuous stocking occurs
○ EU regulations stipulate that birds should be allowed to range outdoors for at least half their lifespan
Routine vaccinations for broilers
Infectious bronchitis
- coronavirus
- respiratory disease
- enteric and renal effects
Infectious bursal disease
- birnavirus
- immunosuppressive
- high mortality in per-acute form
Common conditions in broilers
Chick quality issues, yolk sac infection
Osteomyelitis and arthritis
Coccidiosis
Chick quality issues and yolk sac infection of broilers
Early septicaemia
Result of hatching egg quality, hygiene and management
Breeder health, shell quality, egg hygiene, egg storage
Condensation on eggs is a recipe for disaster in terms of getting infection into the egg
Incubation: temp, humidity, CO2 levels, hatch window, navel
Day old chick: handling, grading, transport, brooding
Coccidiosis in broilers
Acute haemorrhage in caeca
Ubiquitous in poultry production
3 main strains:
- E. acervulina,
- E. maxima,
- E. tenella
Also E. Brunetti and E. necetrix that affect older birds
Very successful parasite
Resistant to disinfectants - persists onsite
Multifactorial impact: damage to gut, affects absorption of nutrients, more ammonia build up in houses, resp disease, poorer absorption of water, watery faeces, problems managing litter, secondary infection: Clostridium - gastric enteritis, predisposes to salmonella and campy
Turkey production
Averaging 9-11kg for hens and 16-22kg for stags
Reared to 6-10 weeks and transferred to grow out sheds
About 16 weeks slaughter for hens, about 25 weeks for stags
Sexed at day old
Toms and hens reared separately
Turkey housing
All year round production primarily housed in typical ‘intensive’ environmentally controlled houses
Xmas production high proportion in ‘alternative systems’
Young turkey poults very vulnerable to environmental conditions, require close detailed attention during brooding
Usually ‘brood’ and ‘move’ system to accommodate differing bird requirements
Birds housed in dedicated brooding houses with heaters, drinkers, and feeders appropriate for their size
At approximately 5-6 weeks of age, birds are transferred to either an ‘alternative’ system or to dedicated controlled environment housing with larger feeders and drinkers of different design
This has an impact on incidence and severity of respiratory disease
‘Alternative’ production system housing can be very basic - i.e. Pole barns
Free range production systems mainly used for the Christmas market
Colony sizes tend to be smaller than broilers or layers, circa 16-20k during brooding and 2-10k during grow out
Colony size during brooding can have a large impact of incidence of respiratory disease (critical colony size)
Intensive production systems may house as many as 500k birds on one farm
Common turkey diseases
Turkey rhinotracheitis
Aspergillosis
Mycoplasma
Orf
Coli-septicaemia
Pasteurella
Erysipelas
Histomoniasis/black head
Avian influenza
Aspergillosis in turkeys
Aspergillus fumigatus (brooder pneumonia)
Occasionally other Aspergillus species involved
Usually associated with poor hatchery hygiene, poor egg hygiene or incubating cracked eggs
Only occurs when the birds inhale large numbers of spores over a short period of time
Rye grass often used in breeder nest boxes, tree bark and wet straw are all high risk for Aspergillus
Round plaque like lesions in the air-sacs
Mortality usually occurs in the first 10 days of life but chronic disease can occur later in life
Small white/green nodular lung lesions seen on post mortem examination
No treatment available, identify and remove the contamination source
May cause 15-20% mortality (more elevate observed)
Pasteurella in turkeys
Fowl cholera
Pasteurella multocida
Organism may persist in URT without symptoms
Signs variable, but up to 40% mortality possible
Sudden death or chronic respiratory disease
PME
§ Lungs show swollen and pinkish ‘cooked’ appearance
§ Blood stained exudate from resp tract
§ Septicaemia changes
Treat with antibiotics (tetracyclines first opinion)
Inactivated vaccines available
Erysipelas in turkeys
Erysipelothrix rhusiopathiae (insidiosa)
Zoonosis - skin rash and cellulitis
Mainly affects older, heavier birds over 13 weeks
Sudden death, birds may be seen to be lethargic with an unsteady gait just prior to death
Chronic disease, scabby skin possible, especially on snood
Liver and spleen usually enlarged and friable, kidneys swollen
Haemorrhages in pericardial fat, gizzard serosa and under pleurae
Treatment: inject bird with procaine penicillin (not licenced and 28 day withdrawal) and benzathine penicillin
Erysipelas vaccine
NB possible false +ve results for Ms Mg for 2 weeks
Histomoniasis/black head in turkeys
Yellow circular lesions on liver are pathognomic
Frothy yellow caecal droppings
Caeci may have fibrosed thick walls
Often on earth floors or free range
Diagnosis
§ Smears of caecal wall contents
§ Liver lesions pathognomic
Treatment:
§ Dimetrazole - licensing issues
§ Chlortetracyclines/Tiamultin combinations
§ Herban (oregano extract)
