Comparison of ammonia emission rates from three types of broiler litters

The objective of this study was to compare the emission of NH(3) from 3 types of broiler litters. Three litter materials (refused tea, RT; sawdust, SDT; and paddy husk, PH) were randomly assigned into 18 cages. Twenty-day-old broiler chicks (n = 216) were randomly allocated into cages and were fed a commercial broiler finisher diet from 21 to 42 d. Three litter samples were taken from each cage on 36 and 42 d. Three subsamples taken from each cage were pooled and analyzed for moisture, pH, and N. Litter samples were incubated for 5 h, and the emitted NH(3) was trapped with boric acid and then titrated with HCl to determine the NH(3) emissions. The emission of NH(3) from RT litter (13.2 mg/kg of litter per h) on d 36 was 61% less than that from SDT and PH. The NH(3) emission rate of RT litter on d 42 (13.0 mg/kg per h) was very similar to that on d 36 (13.2 mg/kg per h). However, emission rates of SDT and PH on d 36 increased by 57.8 and 33%, respectively, when determined on d 42. Emission of NH(3) from RT litter on d 42 (13.0 mg/kg per h) was significantly (P < 0.05) less than that from SDT (54 mg/kg per h) and PH (44 mg/kg per h) litters. When the emission rate was computed as grams of NH(3)/hour/animal unit (AU), the emission rates of RT litter on d 36 (3.4 g/h per AU) and 42 (5.1 g/h per AU) were significantly (P < 0.05) less than that of SDT and PH. The N contents of the RT litter on 36 and 42 d were 6.6 and 6.7%, respectively, and were significantly (P < 0.001) greater than the respective values of SDT and PH. It was concluded that emission of NH(3) from poultry houses could be reduced substantially by using RT as a litter material.