Poultry Team, New-Life Mills
As we progress from spring into the long days of summer, we are reminded that the risk of heat stress in our birds is upon us. During periods of high temperature and humidity birds can experience heat stress potentially leading to large economic losses for poultry producers. As a result, it is critical that producers are prepared and make use of all possible strategies to minimize the losses associated with heat stress.
Birds over 4 weeks of age are the most vulnerable to heat stress. While extreme cases of heat stress can lead to mortality, even moderate stress can have a large impact on production parameters. The most common effects of heat stress in birds include: reduced feed intake, reduced growth rates, drop in egg production, reduced egg weights and deteriorating shell quality.
Whenever temperatures exceed 27⁰C (80⁰F) heat stress will start to become a concern for producers. Besides the impact on production listed above – heat stressed birds will also display certain behaviors. Some behavioral indicators of heat stress that producers should watch out for include:
Nutritional Strategies to Reduce Losses Associated with Heat Stress
Promoting feed intake during periods of heat stress is not recommended. We would actually prefer to see feed intake reduced during periods of heat stress. Ideally, we want to pull birds off feed during the hottest parts of the day thereby reducing the amount of nutrients consumed by the bird. As a result of reducing the nutrient intake by the birds during the heat of the day, we see a decrease in the production of heat produced as a direct result of the digestion and absorption process. This will help prevent the birds from overheating. By reducing feed intake we will enhance the survival rate of the birds which is more important than getting the ideal FCR.
It is essential that birds are provided access to fresh, good quality water at all times. Heat stressed birds will drink significantly more water to help them handle heat stress. Consequently, it is imperative that waterers are at the correct height and readily available to all the birds. Adding electrolytes to the water a few days prior to the onset of excessive heat and throughout the heat stress period until birds are no longer panting will help minimize death losses.
Proper ventilation plays a huge role in limiting the impact of heat stress on poultry. Effective ventilation will remove humid air from the barn and replace it with fresh air from outside. A properly running ventilation system will also ensure that air is dispersed evenly throughout the barn; as air moves through the barn and across the birds, cold air will displace warm air surrounding the bird and provide a cooling effect. You want to make sure that there is good ventilation air flow at the bird level and increase the air speed over the birds. Move as much air as possible over the birds during periods of heat stress.
Some producers will make use of sprinklers, misters or foggers in conjunction with ventilation to improve cooling. While these can be effective tools to improve evaporative cooling, their use should be limited in periods of high humidity as they can actually increase humidity in a barn and negatively impact heat dissipation.