Dietary Manipulation to Reduce Ammonia Emission from High-Rise Layer Houses
Efficacy of dietary manipulation on reduction of ammonia (NH3) emissions from high-rise (HR) layer houses was evaluated for a full year in Iowa. Two HR houses used diet with standard levels of crude protein (CP), designated as Standard, and two comparison houses used an average of 1% lower CP diet supplemented with essential amino acids, designated as Lower CP. Annual mean NH3 emission rate (ER) was 0.81 (±0.21) g d-1 hen-1 or 296 g yr-1 hen-1 for houses using the Lower CP diet, as compared with 0.90 g d-1 hen-1 or 329 g yr-1 hen-1 for houses using Standard diet. Namely, the 1% reduction in dietary CP led to about 10% reduction in NH3 ER. Hen performance of both diets was similar, with hen-day egg production of 80.3% vs. 80.2% for Standard and Lower CP and the corresponding case weight of 48.3 vs. 47.7 lb.