ABSTRACT Rearing environmental conditions are important for turkey production, because this bird is particularly sensitive to heat stress. This study aimed at measuring the wattle temperature response of turkeys of three different ages (61, 96, and 131 days old) exposed to different combinations of dry bulb temperature, relative humidity, and wind speed ranges, as an indication of their physiological responses. The experiment was conducted with 42 male birds housed in a controlled environment chamber and exposed to different combinations of two air speed (WS) ranges (WS1 = 0.3-0.6 ms-1, considered low, and WS2 = 1.2-1.6 ms-1, considered high), dry bulb temperature (DBT) between 22 and 34 °C, and relative humidity (RH) between 40 to 90 %. The statistical analysis showed that WS, DBT, and RH significantly influenced wattle temperature of 61-d-old turkeys, while only WS and DBT influenced this response when turkeys were 96 days old. Furthermore, DBT was highly correlated with both low and high WS. In 131-day-old turkeys, WT response was virtually the same at both wind speed ranges when high DBT was applied. Turkey wattle temperature was influenced by wind speed, and was dependent on both environmental dry bulb temperature and relative humidity, as well as bird age.

This study aimed at evaluating the live performance of turkeys during the initial stage of production (1-26 days of age) and to map the environmental variables inside turkey houses, such as temperature, relative humidity, CO2 concentration, at two distinct minimum ventilation systems. House 1 (H1) was equipped with a negative-pressure ventilation system and House 2 (H2) was equipped with a positive-pressure ventilation system. This study was performed in commercial poultry houses, located in Francisco Beltrão, Paraná, Brazil, in June, 2008. A number of 14,000 turkeys toms at the same age, provided by the same local hatchery and were housed at a stocking density of 23 birds m-2. Three 13 m² boxes with 300 turkeys each were placed inside the poultry houses. All treatments were assigned for the birds inside each of the three boxes. The poultry barns were virtually divided in eight equally distributed in areas where the environmental variables were recorded. The performance parameters measured were weight gain, feed conversion and mortality rate, recorded weekly. Analysis of variance and F-tests were performed to compare results within different environmental conditions, using MINITAB 14 statistical software. The ventilation systems did not significantly influence CO2 concentrations (p = 0.489), whereas temperature (p = 0.016) and relative humidity (p = 0.0001) and feed conversion (p = 0.001) were significantly affected by ventilation system. Temperature and relative humidity in H2 (positive pressure ventilation system) was found to be less aversive than those in H1 (negative pressure system). Also, bids in H2 presented lower feed conversions than those in H1.

Gas production in broiler houses and their emissions are closely related to the microclimate established inside the house according to air temperature, humidity, and velocity. Therefore, the internal house environment is influenced by building typology and ventilation system. The objective of the present study was to evaluate ammonia emission rates in broiler houses equipped with different ventilation systems (negative or positive pressure) and litter conditions (new or built-up). The environment of six commercial broiler houses was evaluated internal and external NH3 concentrations. Ventilation rates were recorded to estimate ammonia emission rates. The efficiency of circulation and exhaust fans was assessed, and higher ventilation rates were determined in negative-pressure houses due to the higher flow of the fans. Houses with new litter increased ammonia emission rates along the rearing period, indicating the relationship between gas emissions, bird age and ventilation rates, and presented a typical curve of NH3 emission increase. Negative-pressure houses with built-up litter presented higher emission rates during the first rearing week due to the high NH3 concentration during the brooding period, when the ventilation rates required to maintain chick thermal comfort are low. Although the results of the present study indicate an advantage of the positive-pressure systems as to gas emissions, further research is needed reduce gas emissions in broiler houses with negative-pressure systems.

This experiment was carried out in a 104 m² poultry house located between the geographical coordinates 25°45'00" south latitude and 53°03'25" west longitude and an average altitude of 550 m, from September to November, 2008. The chickens were placed in 12 pens measuring 2 m² each at a stocking density of 12 chickens m-2. This study aimed at evaluating the effect of two different initial weights (chick weight on first day of experiment) and two types of litter material on broiler production parameters, litter humidity, as well as on breast and footpad lesions. A total of 240 female Cobb® chickens, derived from the same flock of breeders, was distributed in a completely randomized experimental design with a 2 (initial weight) by 2 (litter material) factorial arrangement with three replicates per treatment. Initial weights were classified as light (34.40 - 35.22 g) or heavy (39.29 - 41.30 g), whereas wood shavings and sawdust were used as litter material. Data were analyzed by ANOVA and means were compared by Tukey's test at 95% confidence level. Initial weight significantly influenced bird performance, as chickens with heavy initial weight presented higher feed intake and body weight. Type of litter did not have any effect on breast injuries and litter humidity. However, the wood shavings litter significantly influenced footpad lesions.