2. INTRODUCTION
• The amount of time required for broiler to reach a given target weight has been
considerably reduced due to
1. Improvement in genetics
2. Nutrition
3. Management
• Additionally , processing body weight requirements have become more precise to meet
the demands of market.
These two factors would seems to promote a simpler route to an improved final product.
3. • Producing target weight broiler in reduced amount of time is very challenging for grower
For example: target weight in Saudi Arabia is 1400 grams. In golden chicken, flock weight
differences are noted from 1200 grams to 1400 grams at 27 days age.
• These deviations in flock weight occur even though
Same genetics
Same feed
• Then question: why these differences in target weight occur ?
• It is noted that:
Variation in the house environment, is largely influenced by ventilation, significantly effects
broiler performance and grower/farm manager is responsible for managing ventilation.
4. GROWTH RATE EFFECTS ON INCOME
• A common way to compare growth rates between flocks is to calculate the average daily
gain (AGD)
• Which is simply the: average body weight/age at processing plant
• Comparing these figures revels differences between different growers.
• For example if some flock achieve 44 grams ADG and other achieve 52 grams ADG.
• The difference in these figures shows that for first grower to equal the second 5 days
additional are required.
• Flocks are usually processed at similar age.
• Growers with broiler flocks experiencing poorer weight gains receive significantly less
income.
• These examples shows , seemingly small differences in growth rate can have large
effects on overall productivity.
5. VENTILATION EFFECTS ON GROWTH RATE
AND FEED CONVERSION
• changes in the modern broiler bird have increased the importance of in house
environment factors.
• In response to market requirements, geneticists have raise not only growth rate, but also
the yield of carcass components.
• Extra yield in birds, most of which is concentrated in breast, makes the broiler more
sensitive to high temperatures.
• so ventilation attributes a lot in performance of broiler.
• Broiler genetic lines are selected for growth rate, most of which is determined by their
desire to eat.
6. • If ventilation is not proper, broilers will not eat as much as they could or will not eat at all.
• So proper ventilation elevates the bird performance.
• If the ventilation is not ideal for any part of the day, the potential growth for that part of
the day is lost and can never be regained.
• For example if bird did not eat feed daily for 2 hours due to unpleasant house
environment, it means broiler will not grow for 54 hours out of 648 hors life.
• So it will achieve target weight 2.25 days later.
• If ventilation problem results in cooler than ideal temperatures, broiler will still eat
sufficiently and will grow.
• How ever proportionately more of energy consumed will go towards maintaining normal
body temperature instead of towards growth.
• This will elevates FCR.
7. VENTILATION EFFECT ON COST AND INCOME
• if we place 30000 bird in a house, and birds gain 1200 grams weight instead of 1400
grams in 27 days.
• Then there is loss off 6000 kg weight/ house.
• If the cast of one kg meat is 10 Saudi Riyal then there is loss of 60000 SR/ house.
• If there are 12 houses in a farm then total loss will be 720000 SR.
• If there are 73 houses then total loss will be 4.38 million/flock.
• If there are 8 flocks /year then total loss will be 35.04 million SR./ year as compare to
flocks which gain 1400 gram weight in 27 days.
8. FAN TIMER SETTING CALCULATION
• Calculate the ventilation rate for the house(total cu. meters per hour)
• Total minimum ventilation=minimum ventilation rate per bird*number of birds in the
house.
• Example: one house of 30000 broilers weighing 800 gm at 20 days of age.
• Minimum ventilation rate is 0.594 CMH per bird
• Total ventilation required is 0.594*30000=17820
9. CALCULATE PERCENTAGE TIME FOR
RUNNING OF FANS.
• if fan capacity is 16978 cmh, then
• Percentage of time= total ventilation needed/total capacity of the fans
used
• If we use 2 fans then total fan capacity=2*16978=33956
• Percentage time=17820/33956=0.52=52%
• If 5 mint cycle is used then 2.4 mint off and 2.6 mint on
