Managing Heat Stress With Poultry
With Britain experiencing record temperature levels this year, and extreme weather events becoming commonplace, monitoring livestock health, particularly poultry health, is more important and more challenging than ever before. Heat stress in birds will not only affect your production and profit levels, it can also lead to distress, suffering and even death in your flock.
How does heat stress occur?
Heat stress occurs when birds are no longer able to regulate their own body temperature. Normal poultry body temperature is around 41°C (106°F), with heat produced by their metabolism, including egg production. Like dogs, poultry are unable to sweat, so if their body temperature starts to rise, due to external conditions, then they will begin to pant in an effort to lose heat through evaporation. As panting increases, heat stress starts, with breathing rising to up to ten times normal rates. This, in turn, will tire the birds and make them less able to take action to reduce body heat.
Birds take around five days to acclimatise to temperature changes, so sudden heat waves, particularly early in the year, can be particularly dangerous. Since birds aim to lose heat through panting, hot and humid conditions are more dangerous than hot and dry weather.
Factors in heat stress
There are several factors that will increase the risk of heat stress and adversely affect poultry health. Firstly, the number of birds in the unit is crucial, as heavily grouped birds will be up to 40% less efficient at regulating their body temperature than birds with more space around them. Bird house design is also important, as the correct insulation can significantly reduce the transfer of heat through walls and roofs. On a hot day, as much as 30watts per square metre of heat can be transferred into the bird house through an uninsulated roof. DEFRA recommends a maximum U value for insulation of 0.4 watts per square metre per degree centigrade.
A third factor is ventilation, although this involves much more than simply having openings in the bird house. An air speed of between 1m/s and 3m/s is required to remove the hot boundary layer of air around the bird and remove the humid air from around the head as they pant and so a powered ventilation system is crucial to keep the air moving fast enough. Regulations state that this system must also come with an alarm to warn of failure and that a back-up system must be available to protect poultry health.
Finally, birds must have access to adequate supplies of cool fresh drinking water. This not only helps to reduce body temperature, but also helps to replace fluid lost through panting.
Adding a liquid supplement, such as Vitacool from Kilco, stimulates the birds to consume more water, while also replacing lost electrolytes.
The Welfare of Farmed Animals (England) Regulations 2000 require that all staff involved with the care of birds are trained in the identification and management of heat stress. This includes making them familiar with the relevant welfare codes for ventilation and temperature. Staff must know how to spot the early signs of heat stress so that steps can be taken promptly to protect poultry health and prevent the situation from escalating.
Your local Kilco team are always available with expert advice on poultry care and other farming issues, including a range of products such as Vitacool, to help you manage our changing climate more effectively. As summers get hotter and freak temperature spikes become more common, it is vital that we all work together to protect livestock health.
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