Poultry chickens, while hardy and resilient, are not immune to the challenges posed by heat stress. Imagine a scorching summer day when the sun beats down relentlessly, these conditions can be particularly taxing for our feathered friends. Heat stress in poultry is a serious concern that can impact their well-being and overall productivity.
Summer (Heat) season causes number of deleterious effects on poultry birds like broilers and layers which ultimately reduces profitability. Summer (Heat) stress has been a serious concern for poultry producers as it directly leads to financial losses by impaired poultry performance.
When temperatures soar, chickens, much like humans, can struggle to regulate their body temperature. This can lead to a range of issues, including reduced feed intake, decreased egg production, and even mortality in extreme cases. Understanding the signs of heat stress is crucial for any poultry farmer.
Watch out for telltale signs such as increased panting, wing spreading, and lethargy among your flock. Additionally, a drop in egg production and quality may be indicative of heat-related challenges. Prevention and management are key to ensuring the welfare of your chickens during heatwaves.
Providing adequate shade is a fundamental strategy. Create cool zones within the poultry housing, utilizing natural shade or installing artificial covers. Adequate ventilation is equally important, ensuring proper air circulation helps dissipate heat and maintain a comfortable environment for the birds.
Hydration plays a pivotal role in combating heat stress. Make sure fresh, cool water is readily available at all times. Consider adding electrolytes to their water supply to replenish essential minerals lost during heat-induced stress. Additionally, adjusting feeding schedules to cooler parts of the day can stimulate better appetite and nutrient intake.
Innovative cooling solutions, such as misting systems or evaporative cooling, can be effective in reducing ambient temperatures within poultry houses. These technologies offer a refreshing respite for chickens and contribute to a more conducive environment.
What Exactly Happens to Poultry Chickens in Heat Stress?
Poultry birds become heat stressed when they have difficulty in achieving balance between body heat loss and body heat production, the normal body temperature of poultry being 41ºC.
When environmental temperature exceeds 35ºC bird is likely to experience heat stress. In an effect to maintain body temperature birds first rely on losing heat from blood vessels near surface of skin by process called “non-evaporative cooling”.
However, this mechanism is only effective when ambient temperature is lower than bird’s body temperature. As ambient temperature increases beyond bird’s thermo-neutral zone, non-evaporative cooling becomes ineffective. At these higher temperatures, birds rely on panting/evaporative cooling as mechanism for controlling body temperature.
Panting is an effective but energy expensive way for the bird to control body temperature and typically results in lower feed intake and growth as well as reduced feed efficiency between 20-30ºC feed intakes is reduced by 1-1.5% for 1ºC rise in temperature and by 5% above 32ºC.
This will increase water intake to offset water loss but situation is complicated by the fact that body’s ability to retain water is reduced as the evaporative cooling process escalates.
During high ambient temperatures, the birds increase panting up to 10 times from a normal rate of 25 breathes/min to 250 breathes/min. this leads to an excessive loss of carbon dioxide resulting in raised blood plasma bicarbonate levels and increased pH by excreting bicarbonates via urine.
Bicarbonates are negatively charged ions that must be coupled with positively charged ions such as potassium to be excreted in urine.
However, as potassium is important in maintaining intracellular water balance, a loss of potassium ions via urine reduces ability to maintain this water balance.
Consequently, while birds do compensate for water losses associated with panting by consuming more water, its retention in the body cells is limited by simultaneous loss of electrolytes such as potassium in urine.
Effects of Heat on Poultry Birds
Most important effect of heat stress is decrease in body resistance and more susceptibility to E.coli and CRD etc. in summer outbreaks of gout may be seen in broilers and layers.
In heat stressed birds, blood flow increases upper respiratory tract, skin and abdominal muscles for relieving heat, however, blood flow to intestinal tract is decreased. As a result there is reduction in appetite leading to lower feed intake.
Concurrently water intake is increased resulting in fluid contents in intestinal tract. This further cause’s diarrhea that results in loss of electrolytes needed to maintain acid base balance.
Read Also: Vaccination Program for Poultry Chickens
Clinical Signs or Symptoms
The following clinical signs will be observed in heat stressed birds:
1. Panting/Rapid respiration.
2. More intake of water.
3. Reduced appetite.
4. Reduction of egg production.
5. Poor egg shell quality.
6. Less body weight gain in broilers.
7. Reduced feed efficiency.
8. Increase in body temperature.
1. Dehydrated carcass.
2. Mucoid exudates in mouth and nostrils.
3. Pale/cyanotic combs.
4. Pale breast muscles.
5. Congestion of liver, spleen, kidney and lungs.
6. Fluid contents in intestines.
7. Rapid decomposition of carcass.