1. By: C. E.
Heat Stress in Poultry

2. Staying cool Optimum temperature is 21-24 degrees C No sweat glands
Evaporation of water from surfaces of the lungs and air sacs
Water evaporates
Rate of evaporation increases as temperature increases

3. Hot and Humid Conditions
Drink more water
Respiratory rate increases (20 to 240 breaths per minute)
Seen as panting
Extra waste produces
Drinking water removes extra waste

4. Humidity
When above 50%, there is no marked reduction in heat loss from the lungs
Only a few grams evaporate before the air is saturated

5. Wet Droppings Normal: firm, brown and white
Abnormal: wet, frothy, foamy, yellow
Caused by heat stress from hot and humid environmental conditions
Decreased appetite
Increased water consumption
Treatment:
Add vitamins and electrolytes to plenty of cool water
Stand in cool water
Fan blowing
Shade
Mash feed with cool water

6. Responses Panting Evaporative cooling Loss of water from lungs
breaths/min
Respiratory (metabolic) alkalosis- loss of CO2 and HCO3 (bicarbonate)
Plasma pH up to 8.0
Intracellular pH to acid and potassium is lost
Weaker egg shells (calcium+CO2)

7. How it works

8. Responses Spread Wings Radiate heat from body to ground
Lets circulating air reach the hotter parts of their body

9. Responses Stop Eating/Drink More Shunts Blood Away from Gut
Lower metabolic heat
Cool body through the gut
Shunts Blood Away from Gut
Reduce metabolic heat

13. Signs of Heat Stress: What to Look For
Labored breathing and panting
Pale combs/wattles
Lifting wings away from body
Lethargy
Diarrhea
Seizures/convulsions

14. Prevention Access to water Supplement electrolytes Protection from sun
Don’t crowd
Feed during cooler times
Keep birds calm

15. Resources
ationinPoultry.aspx
system-thermoregulation/
nutrition/how-to-spot-signs-and-prevent-heat-stress-in-chickens
tryandswine/BiochemistryofdietaryelectrolytebalanceinPou/tabid/ 2214/Default.aspx