Gas emissions from three cage layer housingsystems

摘要

Egg production systems have evolved in recent years. In the last two decades, laying hen production systems shifted from deep-pit housing system to manure belt housing system while, in the next decade, they will most likely shifted to furnished cages,non-cage (e.g. slats/litter or aviaries) or free range systems. It appears that no single housing system is ideal from an environmental point of view and a hen welfare perspective. A better understanding of those systems is a key factor in the identification of the environmental hot spots associated with laying hen production systems.The aim of the study was to measure and compare gas emissions, manure characteristics, and egg production from three cage layer housing systems: conventional cage, furnished cage, and cage-free aviary system. The experiment was replicated with 360 hens (Lohmann LSL-Lite) reared in twelve independent bench-scale rooms (mini-barn) during an 11-week period (23-34 weeks of age). The experiment was a completely randomized design with three housing systems and four repetitions.The experiment took place between February and May 2015. Unfortunately, gas emission results were not available at the time this paper was prepared. However, the paper presents a description of the three cage systems, the operating conditions, and the methodology used to measured gas emissions during the experimentation. Averaged NH3 concentration measured in the aviary system were almost 16th times higher than those of the conventional and furnished cages. Bedding as well as manure decomposition has contributed to NH3 production. CH4 and C02 concentrations were similar among the three systems.This research is part of a multi-phase project, including an analysis of the hen welfare by, among others, an assessment of the quality of eggs, blood tests, and an assessment of the behavior of hens in cages. A life cycle assessment approach, combined with an economic analysis, will later be used to compare environmental footprint of the different housing systems.