Online

24/7 knowledge networking from feed to food

blog

How to prevent reduced performance due to Heat Stress in chickens and pigs?

How to prevent reduced performance due to Heat Stress in chickens and pigs?


Chickens and pigs are sensitive to suboptimal climatic conditions. In the summer period, excessive heat and humidity can reduce performance, health and wellbeing of animals.

Chickens

Fast growing broiler chickens and high producing laying hens are vulnerable to heat stress. This is because these producing animals need a high feed intake. The uptake, digestion, absorption and metabolism of food inevitably generates heat in the body. This may lead to heat stress when temperatures are high. 0612131b-1803-4da9-b165-f70af881e29a.jpg
Image 1 - Effect of excessive heat and humidity on broilers and layers

Chickens are losing heat by (image 1):
  • Spreading their wings
  • Panting (image 2 and 3)
  • Being less physically active
  • Increasing their water uptake

a6e892e4-83ff-491a-8246-5fd8550fbe33.jpg
Image 2 - Layers panting

8eb5c1d7-897f-4d36-a6c6-1f20dc617099.jpg
Image 3 - Broilers panting

It is the environmental temperature in combination with the humidity level that determines the level of heat stress. See image 4, which shows that a humidity between 45 and 75 % in combination with a temperature below 30 degrees Celsius is comfortable for chickens. b1b9b26d-7506-4e6c-81ef-6533d2492be5.jpg
Image 4 - Temperature and humidity index

Symptoms and effects of heat stress
Clinical signs of heat stress in layers and broilers are:
  • Increased water consumption 
  • Reduced feed consumption
  • Spreading of wings
  • Lethargy / less activity
  • Panting (breathing with open mouth, see image 2 and 3)
The heat stress in layers will cause a reduction in nutrient and energy availability for egg production. Clinical signs of heat stress in layers may also include:
  • Increased number of thin eggshells
  • Reduced egg production
  • Reduced egg size
When performing post-mortem, lesions that can relate to heat stress are:
  • Dry muscles
  • Thick and dark-coloured blood
  • Swollen kidneys
Side effects
Chronic heat stress may lead to gut wall damage, leaky gut syndrome. This syndrome causes:
  • Integrity of intestinal cells decreases (image 5): chickens are more susceptible to Salmonella and other diseases
  • Secondary infection if sanitary conditions are poor
  • Reduction of digestibility of nutrients
  • Increased plasma endotoxin levels
bd994c9f-3ec1-4aca-9c84-92371bfb901b.jpg
Image 5 - Inflamed intestinal villi make it easier for harmful micro-organisms to enter the body and bloodstream

Prevention 
Feed
Feed is an important factor in prevention of heat stress. Use good quality feed:
  • Limited use of protein and optimized use of amino acids.
  • More fat instead of carbs (carbohydrates), this will reduce the production of heat.
  • Phytogenic additives, like Keprofix Oral, to improve cellular defense and to minimize damage to the intestines.
  • Salicyl Forte wsp to reduce the body temperature. The COX2 inhibitor will decrease the inflammation in the intestines. 
  • Increase dietary energy density by feeding pelletized feed (concentrates).
  • Minimised non-essential amino acids and fibre.
  • Increased availability of antioxidants through the diet such as vitamin C and E by using Anti Stress Forte wsp.
  • Prevent the administration of drugs that negatively impact the resistance to heat of birds, such ad nicarbazin and monensin.
Adjusting feeding times can support birds in a hot climate. Feed 1/3 of the daily feed between 6:00 and 10:00 o’clock. Take the food away during the hottest period of the day (10 to 16). Feed 2/3 of the daily feed between 16:00 and 21:00 o’clock (image 6). d392b5ba-5800-45b0-90cf-56fa9b5420e5.jpg
Image 6 - Feeding times during heat stress

Drinking water Management and climate
Other management measures are:
  • Tunnel ventilation with an air speed of 2m/sec is recommended.
  • When humidity is high (> 70%) incoming air should be cooled, for example by using air conditioning.
  • When humidity is high, water evaporation (for example sprinklers or pad cooling) is not recommended.
Additives
To make the effects of heat stress of less impact on the animals. The following additives are useful. 4746d29b-5099-4840-82b4-f4836b72136c.jpgAntistress Forte wsp contains vitamin C, E and zinc and electrolytes.
  • Vitamin C and E act as anti-oxidants, they protect the cells of the animal against the damage from the heat.
  • Vitamin E and zinc support the immune system, so the animal stays strong despite the heat stress.
  • Zinc also protects the lining of the gut against the leaky gut syndrome.
  • Electrolytes and dextrose protect the animal against dehydration.
If administering Anti Stress Forte wsp is not an option, using Vitamin C as anti-oxidant is a less effective, but suitable alternative. Add 150 grams of Vitamin C in 1,000 litres of drinking water.  7d1b8870-88f4-416e-aadc-e8c23f0eab2f.jpg Keprofix Oral
  • Acidifies drinking water which can contribute to the immune system
  • Reduces bacterial load to avoid infections
  • Essential oil (clove = eugenol) improves digestion and growth performance
It is important to take the hardness/buffering capacity of the drinking water into account when adding Keprofix Oral. Read more about adding Keprofix Oral correctly in this previous newsletter.


Pigs

Most animals can transfer internal heat to the outside of the body by sweating and panting. These are the two most important tools for the maintenance of body temperature. For pigs, this process is less easy, because:
  • Pigs do not sweat. The thick layer of subcutaneous fat they have, works as an insulation layer to keep the cold outside or the heat inside. 
  • Pigs have relatively small lungs, which makes panting harder.
In nature, pigs look for mud to lie in and cool down, this is called “wallowing”. In modern housing, it is not possible for pigs to wallow, so also very difficult to cool down.

255b958c-c16f-4fad-83b2-74f66e2b65ec.jpg
By eating, pigs take in energy for their growth and development. At the same time they also produce heat by eating. At a temperature of 25 degrees Celsius, the feed intake of a pig of 60 kg decreases (image 7).

c6d1339c-ed1c-41ee-bc07-a37b680b165c.jpg
Image 7 - Response of ad libitum fed 60kg pigs to increasing temperatures (read from left to right)

Not only the temperature has an influence on the pigs, it is the combination of temperature and relative humidity, which determines the wellbeing of the pigs (image 8). At an environmental temperature of 28⁰C, appetite is already depressed by 12 %. When also a high relative humidity of 40 % or more is the case, the appetite is depressed by as much as 50 %.

c22139c2-db88-44f1-93f2-a311418b6f5f.jpg
Image 8 - Temperature and humidity index for pigs

Symptoms and effects of heat stress
General symptoms of heat stress in pigs are:
  • High respiration rate
  • Loss of appetite 
  • Drink excessive amounts of water, up to 6 times the normal amount (which increases the loss of electrolytes)
  • Accumulate acids produced within the body (causing a loss of acid/base balance). 
  • Diarrhoea 
  • Death in severe cases
Effect of heat stress on sows:8c882baa-e489-4f88-9ebd-dcb68b36034c.jpg
  • Decreased farrowing rates 
  • Reduced feed intake
  • Lower milk production
  • Lower piglet body weight
  • Increased wean-to-estrus interval
  • Failure to express estrus
  • Higher embryonic death (if early gestation)
  • Higher amount of stillborn piglets (if late gestation)
  • Failure to maintain pregnancy
  • Increased sow mortality
Effect of heat stress on grower/finisher pigs:e28bedcf-c5fa-44f4-a3f4-ce1704681b5a.jpg
  • Reduced feed intake
  • Decreased body weight gain
  • Inconsistent market weights
  • Decreased feed efficiency
  • Higher carcass fat deposits
  • Reduced carcass quality
  • More disease-prone
Side effects:
Leaky gut syndrome can be a side effect of heat stress. This syndrome causes:
  • Integrity of intestinal cells decreases (image 9): pigs are more susceptible to Salmonella and other diseases
  • Secondary infection if sanitary conditions are poor
  • Reduction of digestibility of nutrients
  • Increased plasma endotoxin levels
bd994c9f-3ec1-4aca-9c84-92371bfb901b.jpg
Image 9 - Inflamed intestinal villi make it easier for harmful micro-organisms to enter the body and bloodstream

Prevention 
Feed
Feed is an important factor in prevention of heat stress. Feed good quality food:
  • Limited use of protein and optimized use of amino acids.
  • More fat instead of carbs (carbohydrates), this will reduce the production of heat.
  • Phytogenic additives, like Keprofix Oral, to improve cellular defense and to minimize damage to the intestines.
  • Salicyl Forte wsp to reduce the body temperature. The COX2 inhibitor will decrease the inflammation in the intestines. 
  • Increase dietary energy density by feeding pelletized feed (concentrates).
  • Minimised non-essential amino acids and fibre.
  • Increased availability of antioxidants through the diet such as vitamin C and E by using Anti Stress Forte wsp.
Manage the feeding process as follows:
  • Take away all the food during the hottest part of the day (between 10:00 and 16:00 o’clock).
  • Put the feed back when it cools down or give the food in the middle of the night with the lights on. At night: give the normal quantity of fat, protein and carbohydrates
Drinking waterManagement and climate
Other management measures are:
  • Add roof insulation
  • Reduce stocking density if possible
  • Increase ventilation or sprinklers
Decreasing the temperature in the house can be done by using ventilation or sprinklers. In table 10 and 11 below, you can find the effective decrease of temperature when using this options. Be sure to use ventilation only when the humidity is high. A high humidity in combination with a high temperature is dangerous, because the pigs can no longer release their heat to the air (see image 8 above). Humidity can be measured by using a humidity meter. 

Table 10 - Decrease in temperature when using ventilation8ee48021-ab67-4aad-98ff-fb5b6313b0e2.jpgTable 11 - Decrease in temperature when using sprinklers / vaporizing water (RH = relative humidity)5bf8fe16-8dc2-4e68-bd84-cbba1e3d65a7.jpg


Additives during heat stress
To make the effects of heat stress of less impact on the animals. The following additives are useful.4746d29b-5099-4840-82b4-f4836b72136c.jpgAnti Stress Forte wsp Contains vitamin C, E and zinc and electrolytes.
  • Vitamin C and E act as anti-oxidants, they protect the cells of the animal against the damage from the heat. 
  • Vitamin E and zinc support the immune system, so the animal stays strong despite the heat stress. 
  • Zinc also protects the lining of the gut against the leaky gut syndrome. 
  • Electrolytes and dextrose protect the animal against dehydration.
If administering Anti Stress Forte wsp is not an...

Do you already have an account? Log in here