Effect of ventilation settings on ammonia emission in an experimental pig house equipped with artificial pigs

The aim of this study was to compare the impact of 3 ventilation set-point temperatures (Tset = 21, 23 & 25 °C) on indoor climate and NH3 emission, using 2 pig compartments with underfloor air distribution (UFAD) and equipped with artificial pigs. The artificial pigs consisted of mock-up pigs to simulate heat production and a spraying installation to mimic pig urination by applying urea solution onto the fully slatted pen floors in the test compartments. The study identified ground channel temperature (TGC) as a key factor affecting NH3 emission (P < 0.001). TGC also interacted with Tset (P < 0.001) in effects on NH3 emission. When the reference Tset increased from 23 °C to 25 °C, NH3 emission decreased by 43% at TGC 15 °C and 29% at TGC 18 °C, due to the relative reduction in ventilation rate (VR). At TGC of 22 °C, NH3 emission did not differ between Tset (23 °C) and Tset (25 °C). However, when the reference Tset decreased from 23 °C to 21 °C, NH3 emission did not differ between the 2 set-point temperatures at TGC of 15, 18 and 22 °C. Further tests under practical conditions are needed to confirm these findings and to check for the impact of Tset on pig performance and carcass quality.