Fans and inlets
What factors affect fan capacity?
Restrictions - fan covers [light covers but restricts air movements] (light exclusion and wind shields = outside air velocity & direction can affect how good fans work) shutters
Amount of negative pressure - fans rated against negative pressure = if you buy fans for a barn ask about static pressure range
Air short circuiting - movement back against the fan
Why would manual control inlets be better over computer
can open or close them if there is going to be a dramatic increase or decrease in temperature
What characteristics about an inlet would maximize mixing
Inlet should be close to the ceiling as possible
Surface inlets shouldn't be used
ceiling should be free from obstructions
inlets should be able to direct air downward during hot air
What are the adult temperature requirements? what does it being to high do?
12.8-26 C
For laying hens - 18.3-23 C
high temp effects - Morbidity and mortality, lowers feed intake
What are some gases found in the barns and their sources
Ammonia (NH4), Hydrogen sulfide (H2S), Carbon Dioxide (CO2), Carbon monoxide (CO), Methane (CH4)
Sources - Anaerobic degradation of manure organics, animal respiration, Fuel burning heaters
What are the upper and lower limits in ventilation
minimum ventilation - fan capacity that maintains an acceptable barn environment
Maximum summer capacity for cooling - fan capacity that minimizes the temperature increase in a barn in comparison to ambient air
Why do you not want cold air going right to the floor
Displaces warm air near the floor toward the ceiling - chills the birds
Cold air does not remove water from litter
Results in excessive fuel usage - more heat to remove moisture and warm the birds
When can birds control their temperature? what is there temps? how can they control their temperature
Bird are homeotherms - fully developed by 7-21 days so need temp controlled until then
Adult body temp - chicken = 41.9 C
- Turkey 41.2 C
Methods of heat loss - sensible (direct) or Insensible (indirect - panting)
What are common brooding management practices
Use of brooder guards and attraction lights - have a brooding room or use half of the barn
Bright continuous light - not continuous anymore, by 5 days of age at least 4 hours of darkness, 1 hour before then
Increase number of feeders and waterers
Distribution of feeders and waterers - throughout the barn so that the can't go far without hitting one
Appropriate temp and draft free
What are the adverse effects of ammonia? What is it measured in?
Increased incidence of breast blisters, damaged feet
Keratoconjunctivitis - inflammation of the eye
Measure in PPM
How do you select a fan
Quantity of air delivered at different static pressures
energy efficiency
quality of dealer service and support
reliability and life
suitability for application
Cost - purchase and operating
What needs to happen to the air for effective ventilation
It needs to be conditioned - heat the air, and the moisture holding ability of air changes with temperature
What are ways or sensible (direct) heat control? what's the most important?
Conduction - transfer of heat from molecule to molecule = leaning against a wall
Convection - MOST IMPORTANT - Involves air movement
Radiation - Heat in the form of electromagnetic waves - least important
What are sources of moisture? what humidity level is wanted?
Sources = respiration evaporation, poultry excreta, incoming air, spillage (from water source)
Humidity - 55-70% relative humidity, can be variable during broiler growth
What are some factors affecting ammonia levels
Manure nutrient level - high protein and poorly balanced diets
Litter moisture content - Diet induced water consumption, enteric disease, water spillage, incoming air, ventilation
Barn temperature - hot, moist, humid
What are the functions of air inlets
air entry
air distribution and circulation
facilitate removal of moisture
Pulling air in passively
Why do you want air hitting the ceiling first and coming in fast
Hitting the ceiling allows it to warm up
and coming in fast allows air to mix
What are some thermoregulation methods
Behaviour
Ptiloerection
Vasomotion - blood flow to limbs
Shivering
Panting
What does high humidity do in cold temps
Reduced ventilation, damp litter, increased ammonia, condensation causing damage to building
What are the effects of 10ppm vs 25ppm vs 50ppm vs 100ppm of ammonia? What level does it need to be under
Needs to be under 25ppm, should be under 10
10 = Over several weeks the respiratory tract of turkeys will receive some damage and interfere with the birds' ability to clear bacteria from their lungs
25 = Damage to the lungs and airsacs within 48 hours, bacteria and viruses can more easily invade the lungs and airsacs
50 = lung and airsac damage in 1-2 weeks, delayed sexual maturity, egg numbers will decline in a month or less
100 = Feed intake and body weight will decline significantly over the course of a month, decreased shell thickness and egg size, increased mortality
What is the difference between continuous vs discontinuous inlets
continuous = One large opening
discontinuous = small little windows
What types of mounted inlet should you use? why?
Recessed over surface mounted - Since it directs the air up to the ceiling, and very little to no air escapes out of the sides
What are the brooding temperature requirements? Are turkeys different
Initial period - 30-20 C
Gradual decrease of 2.8 C per week until 21 C is reached
Temperature requirements of modern strains of broilers and turkeys
Turkeys do well at cooler temps 15-16 C
What happens during low humidity with ventilation and early brooding
Excessive ventilation = dusty, poor feathering and growth
early brooding = combination of winter brooding and weak chicks, starveouts (don't eat enough and die)
What is the problems with hydrogen sulfide
extremely dangerous
colourless with characteristic rotten egg smell
heavier than air
potential problem in liquid manure pits when agitated during removal