Reduction of bird heat stress. M. Czarick (University of Georgia)
Published:April 19, 2012
Dr. Mike Czarick, Senior Public Service Associate at University of Georgia, discusses the principles of keeping birds cold during hot weather during the XXII Latin American Poultry Congress, August 2011.
Betaine is highly effective in helping animals handle heat stress through its osmolyte function by keeping water inside the cells without using the Na+ ATP pump which not only consumes energy but also produces additional heat. We have found both lower body temperature and slower panting rate for betaine supplemented animals, resulting in improved intake and gain. Betaine HCl and Betaine Anhydrous work exactly the same way once they are dissolved because they actually exist in equilibrium. Since the pKa is 1.85 for betaine, that means at pH 1.85 50% of the betaine (whether it was consumed as betaine HCl or betaine anhydrous) exists in the protonated form and 50% in the counter-base (i.e. anhydrous) form. The chloride content of betaine HCl is negligible compared to what's already in the diet. Good quality synthetic betaine should work exactly the same as "natural" betaine at a fraction of the cost.
Thank you very much for your presentation. I have 2 questions for you. 1- In a region with hot summer and cold winter, which methods of ventilation will be correct. As we need minimum ventilation in cold weather and tunnel ventilation in summer. 2- In a region with hot and humid summer, what kind of ventilation could help us?
We can also minimize heat stress by increasing the vegetable oils content in feed as well using some stable vitamin C and electrolytes in drinking water.
Another mistake people make is to build low houses with three-tier cage installation. The height of the building helps a lot to boost natural ventilation. Another mistake is to make the width of the house to accommodate 4 rows of cages instead of two or at worst three rows. Roofing materials is also a factor. Asbestos would hold heat in the day and throws them into the house during the colder period of the day which is basically in the night. Zinc roofing sheets would pick up the radiant energy and through them into the house immediately in the daytime thereby wrecking the havoc immediately. Light or white colored long span will reflect some and throw in some. The best is to use straw thatch on top of the roof during the heat periods. Though straw materials attract pest. Rather best is to use silvery roof reflectors as roof covers.
I forgot to mention in my earlier post that chicken don't sweat. As such, they do not lose heat from their skin except the minimal heat radiation from combs and wattles.They thereby resort to panting to release heat from the body, during heat stress which leads excess removal of carbon dioxide from the system. Carbonic acid is used to release significant amount of carbon dioxide. Depletion of carbonic acid raises blood PH. Which is called reactive heat stress alkalosis or metabolic alkalosis. Calcium metabolism is impaired under alkaline PH and so on.
Many thanks great friends for all your contributions and suggestions. If I may add also about the addition of organic chromium into the feed at 500 grams per ton of finished feed . The feeds could be pelletized during hot weather to ensure that the birds gets the complete nutrients from each peck . They would need to peck less thereby exerting less energy during feeding.
It is excellent presentation for understanding control of heat stress through better management of ventilation. Further we need to properly maintain the functioning of evaporative cooling pads & Fans so that they perform as per capacity designed. Choked pads & dirty fans will reduce efficiency of ventilation.
Vit C, Sodium bicarbonate, Betain etc are additional tools to manage heat stress. Again better ventilation has much greater impact (greater than 80% impact).
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