Hungary lies in the temperate zone and has a continental climate, which is thus highly variable. With regard to farm animal production, the too low temperatures in winter and the excessively hot periods in summer are the most problematic; however, the transitional seasons (spring, autumn) can also cause problems because of their treacherous weather conditions. The most important problem in the summer period is heat stress which reduces the performance of animals and can cause huge losses to the poultry industry by elevating the mortality rate.
The optimum body temperature of poultry varies between 40 and 42 ºC on the average; however, this is an estimated value depending on a multitude of factors including species, breed, age and plumage. It is a general statement that heat stress occurs when the environmental temperature reaches 30–35 ºC. The thermoregulatory system of birds markedly differs from that of other species. Birds do not have sweat glands and, thus, they must lose excess heat through the respiratory tract by panting, which means that their respiratory rate increases (evaporative cooling) and the loss of carbon dioxide may lead to respiratory alkalosis. Therefore, maintaining the right electrolyte balance is extremely important in periods of heat stress. A further problem is that extremely hot weather conditions elevate the body temperature, resulting in enhanced cardiac and metabolic activity as well as reduced blood oxygen supply, which may eventually lead to death. In periods of hot weather, the maintenance energy requirement of birds increases because of the need to get rid of excess heat. The feed intake decreases, which has a negative impact on performance and, thus, the birds will no longer be able to produce at the maximum of their genetic capacity. In laying hens, egg production drops drastically and egg size also decreases. Breeders (parent stock birds) will have reduced fertility due to the elevated temperature of the testicles in males, resulting in semen production and mating activity. Thus, the problems listed above affect the poultry sector as a whole.
The protection of birds against heat stress should be based on full compliance with the management technology requirements. In many cases this cannot be achieved because of the obsolete technology used in some farms. However, nutritional solutions provide a possibility to reduce the huge losses caused by heat stress on farms with less modern technology. Our new product, the ThermoControl nutritional concept provides a solution for this specific problem.
ThermoControl provides a new, complex solution for protection against heat stress. Taking into account the reduced nutrient intake of birds with lower feed consumption, ThermoControl provides elevated amounts of dietary energy and amino acids to the birds. The energy density of the diet has been increased by the addition of fat, the utilisation of which involves markedly lower heat production than that of starch. The protein content of the diet has been reduced or remained unchanged despite the elevated amino acid content, while crude fibre content is reduced – both of these changes are aimed at reducing metabolic heat production. To prevent the above-mentioned respiratory alkalosis, we are using sodium bicarbonate in our diets. The international literature has reported that certain plant extracts help in the protection of animals against heat stress. The natural antioxidants present in such phytogenic extracts protect the body against oxidative stress caused by high body temperature, thus reducing the sensitivity of animals to high ambient temperature. The aromatic ingredients constituting our product of high polyphenol content have antioxidant and antimicrobial properties and support the stabilisation of the immune system, and thus this supplementation has a beneficial effect on the production parameters.
In summary, ThermoControl is an efficient response to the challenges posed by heat stress, as its use effectively reduces the negative effects caused by high environmental temperature.
János Fábián Ph.D.
Director of Research & Development