Global statistics are disheartening - due to the effects of rising heat waves alone, poultry farmers lose over 78,000 birds each year. The optimal temperature for poultry well-being and productivity is the so-called "thermoneutral zone" - from 18 to 22°C. When birds are kept in this temperature range, they do not need to expend energy to maintain their body temperature.
Laura Lazdauskienė, a technologist-formulator at the Compound Feeds and Premixes Department of AB Kauno grūdai, explains the signs that a bird is experiencing heat stress.
"When consulting with clients on farms, we often indicate that a bird is experiencing heat stress when we observe increased water consumption, decreased feed intake, or decreased bird body weight. Other symptoms of heat stress include constantly spread wings, skin color changes, increased respiratory rate, birds often squatting on the floor, moving slowly or swaying," says the specialist. "Finally, there is also an increase in mortality, often caused by cardiovascular and respiratory failure."
Heat effects can be managed in advance
However, according to Lazdauskienė, the effects of heat stress can be managed through preventive measures. The specialist identifies a constant supply of cool water and adequate airflow as the main heat management measures.
"Water consumption increases 2-4 times during heat stress. Cool water (ideally around 20°C) promotes absorption and helps reduce the bird's body temperature. I would also recommend measuring the airflow at bird level. Ensure that the airflow is sufficient for the size of the barn and the number of birds. Drinkers should be checked regularly, flush water lines to keep water fresh and cool," advises Laura Lazdauskienė, technologist-formulator at the Compound Feeds and Premixes Department of AB Kauno grūdai.
The expert also identifies bird movement, feeding time control, and lighting conditions as equally important preventive measures. "We advise clients to reduce the birds' movement area so that they remain as calm as possible during the hottest part of the day. It is also advisable to control feeding time, as birds tend to eat more in the morning, which accelerates metabolism due to digestion and makes birds even more sensitive to heat. In this case, lighting regulation can be used to encourage birds to eat at night," Lazdauskienė shares her advice.
Speaking of feeding, the specialist adds that the feed should have more nutrients during the hot period, as this compensates for the reduced feed intake. It is also advisable to use drinking water additives, vitamins such as A, D, E and the B complex, which can effectively reduce broiler mortality from heat. Electrolytes also compensate for heat stress caused by the loss of potassium, sodium, phosphorus, magnesium and zinc. Potassium can also increase birds' drinking water intake. The expert advises starting to use electrolytes even before the heat stress period.
"Numerous studies have shown that the use of certain feed additives (e.g., probiotics, vitamins C, E and A, zinc and selenium) has had a positive effect in reducing the harmful effects of heat stress," summarizes Laura Lazdauskienė, technologist-formulator at the Compound Feeds and Premixes Department of AB Kauno grūdai.