Keeping birds cool and combatting the negative impacts of heat stress will be essential to optimise productivity
Heat stress in birds caused by elevated temperatures particularly during the summer, is a major challenge for poultry and egg production, resulting in considerable economic losses. Making the right decisions and implementing appropriate management and nutrition measures in anticipation of a temperature rise will help mitigate the adverse effects of heat stress in layers and broilers.
“Birds are homeothermic animals, which means that they are able to maintain a constant body temperature even with variations in environmental temperature,” says Amanda Mantovani, technical support co-ordinator with Trouw Nutrition GB. “This range is 18 -25 °C and is called the thermoneutral zone. When the environmental temperature drops below the comfort zone the bird suffers ‘cold stress’ and they activate physiological mechanisms for heat production.
“When the temperature is above this range, the bird goes into ‘heat stress’ and starts to use mechanisms for heat dissipation. Moderate conditions of cold or heat outside of the comfort zone can negatively impact production and moderate to extreme conditions of cold or heat can increase mortality rates.”
Increasingly warm temperatures especially in the summer makes it a challenge for poultry producers to keep the birds at a temperature that does not interfere with welfare and production. Feed intake, egg production, egg weight, shell quality, albumen quality and growth rate are just some of the parameters which are detrimentally affected by heat stress. In addition, there can be an increase in cannibalism and mortality.
“Symptoms indicating birds are exposed to high temperatures include increased breathing rate, panting with the beak open to lose heat by evaporation, or lying down to keep the chest in contact with the ground so increasing the surface area contact for loss of heat by conduction. They also open their wings to increase heat loss by convection and can increase water consumption.”
Increased water consumption leads to an imbalance in the mineral metabolism and more water is deposited in the litter which results in a higher level of ammonia production. Depending on the severity of heat stress, birds resort to other physiological mechanisms such as increasing body pH and cortisol production. Besides that, body energy is used for other functions to try to dissipate heat, which effects growth and performance, leading to considerable economic losses. It is estimated that a bird can lose about 540kcal of energy for each 1ml of evaporated water.
“To mitigate these problems, poultry farmers can adopt the use of some equipment that has already been well explored, such as fans, curtains, evaporative cooling pads, fogging nozzles, timers, static pressure controllers and thermostats. In addition to these management strategies, Trouw Nutrition has explored the supplementation of minerals to help the birds in the summer heat. Farm-O-San Anti-Heat Stress (AHS) is a water-soluble powder which contains all the supplemental ingredients a bird needs to help them cope better with elevated temperatures and high humidity levels.”
Trouw Nutrition Poultry Research Centre carried out a trial with three treatment groups to compare the effect of Farm-O-San AHS. Two groups were treated with Farm-O-San AHS, one group was not treated. All animals were exposed to a temperature of 35°C for 10 hours a day. The results show that the groups treated with Farm-O-San AHS had a higher growth and feed intake, reduced feed conversion rate and corticosteroid levels, and reduced the body pH to a desired level showing they coped better with higher temperatures (see table).
Farm-O-San AHS can be used before birds start to show signs of discomfort in periods of high temperatures to prevent a drop in performance. The usage rate should be 1kg/1000 litres of water. If the temperature increase is sudden and the birds are already showing signs of discomfort, a reactive treatment can be applied at a higher inclusion rate of 2kg/1000 litres to mitigate negative effects.
“Maintaining the birds’ thermal comfort is essential for performance in poultry and egg production. Farm-O-San AHS is a powerful tool to help mitigate and optimise poultry performance during summer,” Mantovani concludes.