Broiler production is a prime example of high density animal production. Broilers are often grown in production houses containing 20 000 birds or more at densities of 0.06 m 2 per bird. Broiler litter typically contains 4 to 6 % nitrogen, much of which is in the NH 3 or NH 4 + form. The mixture of litter and manure is effectively a nitrogen storehouse. Under the proper conditions, a considerable quantity of this nitrogen will be released as ammonia (Carr et al., 1990). Many factors, such as season of the year, ambient temperature and humidity, bird health, and management practices can influence ammonia volatilization from broiler rearing facilities (Coufal, 2005). Ammonia is formed from the breakdown of nitrogenous waste products in poultry manure (undigested proteins and uric acid) by exogenous enzymes produced by microorganisms. Factors that exhibit direct control over these processes have been identified as pH, temperature, and moisture (Elliot and Collins, 1982). Ammonia release is depressed at pH < 7 but is very high at pH > 8 (Parker et al., 2005). Therefore, in a commercial broiler grow-out facility, pH would seldom be a factor determining NH 3 volatilization since the pH of broiler litter is Supported by Slovak-Norwegian Project No. 2032051 "Reducing Environmental Impact from Large-Scale Animal Production in Slovak Republic". ABSTRACT:The research reported in this article attempts to address the ammonia problem by quantifying the effect of several variables on ammonia concentrations and emissions. These variables include litter temperature, litter age and ventilation rate. Data was collected in a commercial tunnel-ventilated grow-out facility with deep litter, designed for 25 000 broilers, during 6 consecutive flocks. Birds were housed from hatching to approximately 40 days of age. Litter temperature and litter age were positively correlated (P < 0.0001) with the production of ammonia gas. The amount of ammonia emissions increased with the litter age (P < 0.0001) as a consequence of both the increased ammonia concentration and the ventilation rate (P < 0.0001). The lowest concentrations of NH 3 were observed in a "summer" period, although ammonia emissions tended to be higher just in summer months because of a higher ventilation rate. The elevated levels of ammonia in winter were attributed to the lower ventilation rate during cold weather. After the evaluation of ammonia emissions it can be concluded that during the grow-out period of broilers kept on renewed litter there is an average loss of 6.18 g ammonia per bird and/or 0.043 kg of ammonia per bird yearly. The increase in litter temperature during grow-out periods is a process which could be controlled to prevent excessive ammonia volatilization from housing facilities.

AbstrAct:The quantification of emissions of greenhouse gases from human activities is of prime importance for determining the importance of their effect on the environment. The aim of this study was to test a hypothesis that the interior concentration and emission of carbon dioxide in chicken housing is impacted by the age of animals and season of fattening period. Carbon dioxide (CO 2 ) concentrations and emissions were assessed over six fattening periods in total. The major part of CO 2 seemed to have its origin in bird respiration with assumed production of approx. 147 kg of CO 2 /h. CO 2 emission was most affected by chickens towards the end of the grow-out period (P < 0.001) taking dominance over the process of natural gas burning by heaters. The mean CO 2 emission from the chicken house ranged between 120 and 247 kg/h in the first quarter of periods and between 325 and 459 kg/h in the last ones. The heaters could be theoretically a possible source of approx. 39 kg each hour if they worked continuously. CO 2 emissions were considerably more affected by ventilation rate (P < 0.001) than by CO 2 concentration in the indoor air.

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