Heat stress occurs when animals are exposed to temperatures above their optimal range and can have detrimental impacts. For chickens, their normal body temperature is 41°C and their optimal growing temperature is 21-24°C. When temperatures exceed this range, chickens begin panting to cool down through evaporative cooling, which leads to respiratory alkalosis and electrolyte imbalances that decrease performance and increase mortality. Supplementing electrolytes can help balance acidity but increases litter moisture, while supplements like betaine improve performance without worsening litter conditions.
Heat Stress ;IT`S YOUR DECISION; DO YOU WANT :[GROWTH AND SURVIVAL]Reza Vakili
Publication recommended :
-R. Vakili* and A. A. Rashidi.The effects of dietary fat, vitamin E and zinc supplementation on fatty acid composition and oxidative stability of muscle thigh in broilers under heat stress.African Journal of Agricultural Research Vol. 6(12), pp. 2800-2806, 18 June, 2011
-R. Vakili*, R. Daliri, 2010.The effect of different levels of vitamin e on humoralimmunity, and performance in broiler chicks.Journal of Veterinary Research. 2010, 65(3), pp. 239–244.
https://www.sid.ir/En/Journal/ViewPaper.aspx?ID=259982
-R. vakili, A.A. Rashidi and S.sobhanirad.2010. Effects of dietary fat, Vitamin and zinc supplemention on tibia breaking strength in female broilers under heat stress.Afican journal of Agricultural Research.Vol. 5(23), pp. 3151-3156, 4 December, 2010.
-A.A. Rashidi, y. Gofrani Ivari, A. Khatibyoo and R. Vakili.2010.Effects of dietary fat, Vitamin and zink on Immune Respanse and Blood Parameters of Broiler Reared under Heat stress. Medwell Journals Research journal of poultry Sciensce. 3(2):32-38
Reza Vakili.2021. Impact of different oil sources on mitigating negative effects of heat stress on performance, thigh proximate composition, fatty acids profile, bone status and immunity of broilers. Journal of Animal nutrition and physiology (under review).
In the tropical climate like India, the high ambient temperature along with high humidity is the major stressor (abiotic), thus resulting in the HEAT STRESS a major concern of poultry production.
55°F – 75°F Thermoneutral zone
65°F – 75°F Ideal temperature zone
75°F – 85°F A slight reduction in feed consumption
85°F – 90°F Feed consumption falls further, cooling should be started before this temp is reached.
90°F - 95°F Feed consumption continues to drop, danger of heat prostration among layers, cooling .
95°F-100°F Heat prostration, water consumption is high.
>100°F Emergency measures must be taken, survival is concern at these temperatures.
CONCEPTS AND STRATEGIES TO AMELIORATE THE HEAT STRESS
1. Environmental strategies
Intermittent Photoschedule(light).
2. Housing management
Sites election, design and construction, ventilation, internal and roof cooling, Density of birds.
3. Nutritional strategies
Increasing energy density
Dietary Protein level and Amino acid composition
Vitamins – A,C,E.
Minerals.
Non nutrient feed additives.
Water and electrolyte balance.
4. Feeding strategies
Early feeding
Intermittent feeding
Sex separate feeding
Fasting or feed with drawl.
5. Genetic strategies
Selection for heat tolerance.
Selection for disease resistance.
Use of major genes – Naked neck(Na), Frizzle(F), Dwarf(dw), Silky (h), Slow feathering (K).
ENVIRONMENT STRATEGIES:
A). Intermittent Photo schedule
An intermittent light regime can improve the feed efficiency and thus the broiler production efficiency, by decreasing the fat deposition associated with increased incidence of leg abnormalities, metabolic and cardiovascular diseases, ascites.
The favourable effect is related to the lower heat production during both light and dark period, although fluctuations in heat production are following closely the light-dark alternation.
This photo schedule contains more than one scotophase and one darkphase which recur at 24 hr intervals.
This regime increases the feed consumption during cooler part of the day.
Symmetric - when scotophase and dark phase are of equal length.
Asymmetric - when they are not in equal length.
3weeks age of broiler raised under 2L:4D intermittent light regime were significantly lighter than broilers raised in continuous light schedule but at 7 weeks it is reverse.(Proudfoot, 1975).
The initial reduction in body weight gain of birds under intermittent schedule is followed by compensatory growth, but the compensatory growth depends on genotype and sex.
Boschouwers and Nicaise (1992) observed that physical activity in broilers were lowest under 100Hz fluoroscent light and highest under incandescent.
HOUSING MANAGEMENT
Orientation : east west to reduce direct solar radiation
Shade of trees and green crops around the houses will prevent direct heating, .vegetation should be mowed frequently so that it doesnot obstruct air flow
Houses should be oriented perpendicular to wind direction for max
Stress, Poultry, heat and Cold Stress, Thermoregulation in Poultry, Behavioral Changes in Poultry, Housing Management, Feeding, Breeding Management in Stress, Diseases in Stress
Combating heat stress of poultry by dietary manipulationMusabbir Ahammed
Poultry heat stress problem occurs severe production fall. Heat stress may overcome by improved management, special care and also dietary manipulation. This slide is the good opportunity to obtain knowledge how to resolve heat stress problem of poultry especially chicken. I hope it would be helpful for both poultry producers and poultry researchers.
How To Do Poultry Farming in Summer? The article written by Mr. Rakesh Kumar, Marketing Director, Growel Agrovet Private Limited, has been published in Poultry Square magazine, May – 2021 edition.
Heat Stress ;IT`S YOUR DECISION; DO YOU WANT :[GROWTH AND SURVIVAL]Reza Vakili
Publication recommended :
-R. Vakili* and A. A. Rashidi.The effects of dietary fat, vitamin E and zinc supplementation on fatty acid composition and oxidative stability of muscle thigh in broilers under heat stress.African Journal of Agricultural Research Vol. 6(12), pp. 2800-2806, 18 June, 2011
-R. Vakili*, R. Daliri, 2010.The effect of different levels of vitamin e on humoralimmunity, and performance in broiler chicks.Journal of Veterinary Research. 2010, 65(3), pp. 239–244.
https://www.sid.ir/En/Journal/ViewPaper.aspx?ID=259982
-R. vakili, A.A. Rashidi and S.sobhanirad.2010. Effects of dietary fat, Vitamin and zinc supplemention on tibia breaking strength in female broilers under heat stress.Afican journal of Agricultural Research.Vol. 5(23), pp. 3151-3156, 4 December, 2010.
-A.A. Rashidi, y. Gofrani Ivari, A. Khatibyoo and R. Vakili.2010.Effects of dietary fat, Vitamin and zink on Immune Respanse and Blood Parameters of Broiler Reared under Heat stress. Medwell Journals Research journal of poultry Sciensce. 3(2):32-38
Reza Vakili.2021. Impact of different oil sources on mitigating negative effects of heat stress on performance, thigh proximate composition, fatty acids profile, bone status and immunity of broilers. Journal of Animal nutrition and physiology (under review).
In the tropical climate like India, the high ambient temperature along with high humidity is the major stressor (abiotic), thus resulting in the HEAT STRESS a major concern of poultry production.
55°F – 75°F Thermoneutral zone
65°F – 75°F Ideal temperature zone
75°F – 85°F A slight reduction in feed consumption
85°F – 90°F Feed consumption falls further, cooling should be started before this temp is reached.
90°F - 95°F Feed consumption continues to drop, danger of heat prostration among layers, cooling .
95°F-100°F Heat prostration, water consumption is high.
>100°F Emergency measures must be taken, survival is concern at these temperatures.
CONCEPTS AND STRATEGIES TO AMELIORATE THE HEAT STRESS
1. Environmental strategies
Intermittent Photoschedule(light).
2. Housing management
Sites election, design and construction, ventilation, internal and roof cooling, Density of birds.
3. Nutritional strategies
Increasing energy density
Dietary Protein level and Amino acid composition
Vitamins – A,C,E.
Minerals.
Non nutrient feed additives.
Water and electrolyte balance.
4. Feeding strategies
Early feeding
Intermittent feeding
Sex separate feeding
Fasting or feed with drawl.
5. Genetic strategies
Selection for heat tolerance.
Selection for disease resistance.
Use of major genes – Naked neck(Na), Frizzle(F), Dwarf(dw), Silky (h), Slow feathering (K).
ENVIRONMENT STRATEGIES:
A). Intermittent Photo schedule
An intermittent light regime can improve the feed efficiency and thus the broiler production efficiency, by decreasing the fat deposition associated with increased incidence of leg abnormalities, metabolic and cardiovascular diseases, ascites.
The favourable effect is related to the lower heat production during both light and dark period, although fluctuations in heat production are following closely the light-dark alternation.
This photo schedule contains more than one scotophase and one darkphase which recur at 24 hr intervals.
This regime increases the feed consumption during cooler part of the day.
Symmetric - when scotophase and dark phase are of equal length.
Asymmetric - when they are not in equal length.
3weeks age of broiler raised under 2L:4D intermittent light regime were significantly lighter than broilers raised in continuous light schedule but at 7 weeks it is reverse.(Proudfoot, 1975).
The initial reduction in body weight gain of birds under intermittent schedule is followed by compensatory growth, but the compensatory growth depends on genotype and sex.
Boschouwers and Nicaise (1992) observed that physical activity in broilers were lowest under 100Hz fluoroscent light and highest under incandescent.
HOUSING MANAGEMENT
Orientation : east west to reduce direct solar radiation
Shade of trees and green crops around the houses will prevent direct heating, .vegetation should be mowed frequently so that it doesnot obstruct air flow
Houses should be oriented perpendicular to wind direction for max
Stress, Poultry, heat and Cold Stress, Thermoregulation in Poultry, Behavioral Changes in Poultry, Housing Management, Feeding, Breeding Management in Stress, Diseases in Stress
Combating heat stress of poultry by dietary manipulationMusabbir Ahammed
Poultry heat stress problem occurs severe production fall. Heat stress may overcome by improved management, special care and also dietary manipulation. This slide is the good opportunity to obtain knowledge how to resolve heat stress problem of poultry especially chicken. I hope it would be helpful for both poultry producers and poultry researchers.
How To Do Poultry Farming in Summer? The article written by Mr. Rakesh Kumar, Marketing Director, Growel Agrovet Private Limited, has been published in Poultry Square magazine, May – 2021 edition.
Ventilation is necessary in modern controlled poultry houses to provide fresh air into the house and to expel noxious gasses from the house to keep the environment fresh and birds healthy.
There are different types of ventilation depends on the weather like minimum ventilation in cold weather, transitional ventilation in optimum weather and tunnel ventilation in extreme weather.
Factors influencing the nutrient requirements in poultrySunil Yadav
This Presentation will help you to understand the various factors that are responsible for the nutrient requirement of poultry. While formulating feed for any classes of poultry we should consider all these factors for a better outcome from the bird.
The objective of a defined feeding management program is to supply a range of balanced diets that satisfy the nutrient requirements at all stages of development & that optimize efficiency and profitability without compromising bird welfare or the environment.
The presentation discusses in detail the efficacy and multipurpose use of an environmentally controlled poultry house and.It basically determines the efficacy of each section of the EC poultry house.
A broiler management course is a program designed to educate farmers, poultry producers, and other interested individuals on the best practices for managing broiler chickens. Broiler chickens are raised for meat production and require specialized care to ensure their growth, health, and well-being. The course typically covers various aspects of broiler management, including housing, feeding, health management, and disease prevention. It may also cover topics such as breeding, hatching, and marketing of broiler chickens. Participants in a broiler management course will learn about the different types of broiler housing and the best practices for managing temperature, ventilation, and lighting to ensure optimal growth and production. They will also learn about the various types of broiler feed and how to formulate a balanced diet that meets the nutritional requirements of broiler chickens. Health management is a critical aspect of broiler management, and the course will cover topics such as biosecurity measures, vaccination programs, and disease diagnosis and treatment. Participants will learn how to recognize common health problems in broiler chickens and how to implement preventative measures to keep their flocks healthy. Marketing is also an important aspect of broiler management, and the course may cover topics such as market analysis, pricing strategies, and distribution channels. Overall, a broiler management course provides participants with the knowledge and skills needed to raise healthy, productive broiler chickens, and to operate a successful broiler farming business.
https://physioaadhar.com/
Thermoregulation is a process that allows your body to maintain its core internal temperature. All thermoregulation mechanisms are designed to return your body to homeostasis. This is a state of equilibrium. A healthy internal body temperature falls within a narrow window.
Ventilation is necessary in modern controlled poultry houses to provide fresh air into the house and to expel noxious gasses from the house to keep the environment fresh and birds healthy.
There are different types of ventilation depends on the weather like minimum ventilation in cold weather, transitional ventilation in optimum weather and tunnel ventilation in extreme weather.
Factors influencing the nutrient requirements in poultrySunil Yadav
This Presentation will help you to understand the various factors that are responsible for the nutrient requirement of poultry. While formulating feed for any classes of poultry we should consider all these factors for a better outcome from the bird.
The objective of a defined feeding management program is to supply a range of balanced diets that satisfy the nutrient requirements at all stages of development & that optimize efficiency and profitability without compromising bird welfare or the environment.
The presentation discusses in detail the efficacy and multipurpose use of an environmentally controlled poultry house and.It basically determines the efficacy of each section of the EC poultry house.
A broiler management course is a program designed to educate farmers, poultry producers, and other interested individuals on the best practices for managing broiler chickens. Broiler chickens are raised for meat production and require specialized care to ensure their growth, health, and well-being. The course typically covers various aspects of broiler management, including housing, feeding, health management, and disease prevention. It may also cover topics such as breeding, hatching, and marketing of broiler chickens. Participants in a broiler management course will learn about the different types of broiler housing and the best practices for managing temperature, ventilation, and lighting to ensure optimal growth and production. They will also learn about the various types of broiler feed and how to formulate a balanced diet that meets the nutritional requirements of broiler chickens. Health management is a critical aspect of broiler management, and the course will cover topics such as biosecurity measures, vaccination programs, and disease diagnosis and treatment. Participants will learn how to recognize common health problems in broiler chickens and how to implement preventative measures to keep their flocks healthy. Marketing is also an important aspect of broiler management, and the course may cover topics such as market analysis, pricing strategies, and distribution channels. Overall, a broiler management course provides participants with the knowledge and skills needed to raise healthy, productive broiler chickens, and to operate a successful broiler farming business.
https://physioaadhar.com/
Thermoregulation is a process that allows your body to maintain its core internal temperature. All thermoregulation mechanisms are designed to return your body to homeostasis. This is a state of equilibrium. A healthy internal body temperature falls within a narrow window.
Thermoregulation is a process that allows your body to maintain its core internal temperature. All thermoregulation mechanisms are designed to return your body to homeostasis. This is a state of equilibrium. A healthy internal body temperature falls within a narrow window.
Temperature practical cum theory part by Pandian M, From DYPMCKOP. This PPT f...Pandian M
INTRODUCTION
HOMEOTHERMIC ANIMALS
POIKILOTHERMIC ANIMALS
BODY TEMPERATURE
Normal Body Temperatures
VARIATIONS OF BODY TEMPERATURE
Pathological Variations
HEAT GAIN OR HEAT PRODUCTIONIN THE BODY
HEAT LOSS FROM THE BODY
Regulation of Body Temperature
Hypothalamus has two centers which regulate the body temperature:
Applied
The drawbacks of climate change are so overt. The Disturbance of Great Ocean Conveyor currents led to the extreme changes in temperature around the globe in the form of a cooler northern, warmer tropical and cooler snowy winter, warmer summer. Many deaths from hypothermia were reported especially in refugee camps as it is not well equipped. Hypothermia is a medical emergency that occurs when the body loses heat faster than it can produce heat, causing a dangerously low body temperature. Normal body temperature is around 98.6 F (37 C). Hypothermia occurs as the body temperature falls below 95 F (35 C). When body temperature drops, heart, nervous system and other organs can't work normally. Left untreated, hypothermia can eventually lead to complete failure of heart and respiratory system and eventually to death.
البوست ده عمل خيري ...
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
شير لعلها تكون المنجية لنا جميعا
This post is for charity ...
Links to PowerPoint presentations in poultry diseases, medications, and immunity in addition to soft skills courses
Share to benefit others
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in powerpoint
https://lnkd.in/gJGGnPY
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination and immunity
Link to download presentations in powerpoint
https://lnkd.in/g2ef7DP
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in powerpoint
https://lnkd.in/g8W7TYq
Presentations are continuously updated
المكتبة متجددة باستمرار
البوست ده عمل خيري ...
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
شير لعلها تكون المنجية لنا جميعا
This post is for charity ...
Links to PowerPoint presentations in poultry diseases, medications, and immunity in addition to soft skills courses
Share to benefit others
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in powerpoint
https://lnkd.in/gJGGnPY
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination and immunity
Link to download presentations in powerpoint
https://lnkd.in/g2ef7DP
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in powerpoint
https://lnkd.in/g8W7TYq
Presentations are continiously updated
المكتبة متجددة باستمرار
Seven Cs of Effective Communication_Life Time Example.pptxOssama Motawae
"عسى ان يكون علما ينتفع به"
Communication
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in PowerPoint
https://drive.google.com/open?id=1EtFtygmlvOYqjqpanRTIgoExIENd-YIB
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination, and immunity
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1znC0qeHMivV2ai4_IUweA-VTBQLJSVKu
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1R3CqcFO10bOyi1aRQx0WNSn6B5TMNMxu
Seven Cs of Effective Communication_Tips.pptxOssama Motawae
"عسى ان يكون علما ينتفع به"
Communication
"عسى ان يكون علما ينتفع به"
Communication
دي لينكات لمحاضرات في امراض وادوية الدواجن وكورسات التنمية البشرية ... جميع المحاضرات بصيغة بوربوينت
ادوية علاج الدواجن من المضادات الحيوية ومستخلصات الأعشاب
Poultry medications (antibiotics and herbal extracts)
Link to download more presentations in PowerPoint
https://drive.google.com/open?id=1EtFtygmlvOYqjqpanRTIgoExIENd-YIB
امراض الدواجن البكتيرية والفيروسية واساسات التحصينات ومناعة الطيور
Poultry diseases, vaccination, and immunity
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1znC0qeHMivV2ai4_IUweA-VTBQLJSVKu
كورسات التنمية البشرية
Soft skills courses
Link to download presentations in PowerPoint
https://drive.google.com/open?id=1R3CqcFO10bOyi1aRQx0WNSn6B5TMNMxu
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
2. Heat Stress Definition
What is heat stress?
– It is a condition that occurs when an animal is exposed to above
optimal temperatures and humidity.
What is its impact?
– Heat stress generally changes a bird’s physiology and places stress on
many systems thereby causing decreased performance, possible
welfare concerns, and even increased mortality.
3. Normal Figures
› Normal broiler body temperature is 41 C.
› Optimum growing temperature is 21 to 24 C.
› Heat stress can be elicited by conditions such as high
temperature and high humidity depending on age.
4. Heat Stress Cost
› A decade ago it was estimated that heat stress costs the
broiler industry 128 million dollars annually.
6. Chickens Cooling Mechanisms
› Chickens have cooling mechanisms that allow them to
survive at above optimal temperatures.
7. Cont. …
› There are two main methods that chickens use:
1. Non-evaporative cooling
› It occurs via convection.
› It is enhanced by air movement in the house
2. Evaporative cooling
› It occurs through the evaporation of water from the lungs.
› It is enhanced by low humidity and increased respiratory rates.
› Increased respiration rate results in carbon dioxide loss and acid-base
balance alterations.
8. Cont. …
› When ambient temperature is lower than body temperature;
– Non-evaporative cooling is more efficient than evaporative cooling
and is therefore the first line of defense.
› When ambient temperature rises to near body temperature;
1. Non evaporative cooling becomes ineffective
2. Evaporative cooling becomes necessary.
3. Respiration rate will increase thereby initiating a higher rate of
evaporative cooling.
9. Cont. …
› When both ambient temperature and relative humidity rise,
– The problem will be complicated, since evaporative cooling rate is
inversely related to humidity.
11. Impact of Heat Stress
Where are the impacts result from?
– When temperatures exceed the effective range for non-
evaporative cooling, the way that chickens cool themselves
(increase in respiration rate will initiate a higher rate of
evaporative cooling) causes certain physiological changes
that further complicate the issue.
12. Cont. …
1. Alkalosis
– Evaporative cooling is accomplished by increasing the respiratory rate
also known as panting, and this can lead to respiratory alkalosis.
– Respiratory alkalosis is a medical condition in which increased
respiration elevates the blood pH beyond the normal range (7.35-
7.45) with a concurrent reduction in arterial levels of carbon dioxide
2. Electrolyte imbalance
– Acid-base imbalance has been shown to cause electrolyte imbalance
and increased electrolyte excretion, mainly K+ and Na+
13. Cont. …
› Acid-base imbalance and the resulting electrolyte imbalance,
caused by heat-induced panting, may play a big part in the;
1. Decreased performance
2. Altered meat quality
3. Increased mortality
15. Overcoming Impacts of Heat Stress
Some supplements may help birds overcoming impacts of heat
stress;
1. Electrolyte supplements
2. Non-electrolytes supplements
16. 1- Electrolytes Supplements
Benefits of supplementing electrolytes to heat stressed birds
via feed or drinking water
1. Increase performance
2. Decrease mortality
3. Improve acid-base balance
17. Cont. …
Side effects of adding extra electrolytes to heat stressed birds
1. Increase excreta moisture
2. Increase litter wetness, a known cause of foot pad dermatitis in
turkeys.
18. 2- Non-Electrolytes Supplements
Adding non-electrolyte feed additives
› Many studies have shown benefits from the inclusion of non-
electrolyte feed additives in broiler diets, such as betaine,
which is a non-ionic organic osmolyte.
› This molecule has also been shown to improve the
performance of heat stressed broilers, but unlike electrolytes
it has not been shown to increase litter wetness.
Notes de l'éditeur
It is understood that chickens have means to cool themselves, but due to its ineffectiveness under certain climatic conditions, proper management is paramount.
Foot pad dermatitis is a welfare concern as well as a production issue, since feet are a major poultry export product from some countries such as the United States of America.