An environmental nuisance: odor concentrated and transported by dust.

Intensive swine production generates odorous emissions which flow from the buildings housing the animals. High ventilation rates bring in fresh air, remove heat and moisture and enhance pork productivity. Numerous compounds contribute to the uniquely offensive odors from swine facilities, including fatty acids, amines, aromatics and sulfur compounds. Dust particles, which originate predominantly from feces and feed, can adsorb and concentrate odorants in swine facilities. In addition, organic particles can decay and generate odorous compounds. Odorants can exist in much higher concentrations in the dust particles than in equivalent volumes of air. Thus, inhalation of odorous dust and deposition of the dust particles in the mucus overlying the olfactory mucosa are likely responsible for some odor-related complaints by swine farm neighbors. Accurate prediction of odor transport and dispersion downwind from swine farms may require models of dust dispersion and correlation between dust and odorant levels. Unfortunately, many approaches to estimating odor impact currently incorporate filtering of air to remove particulate matter before sensing by humans or electronic sensors. Accelerated progress in understanding this and other 'real world' odor control problems will require methodological innovations that allow quantification of odor in response to air streams containing vapor and particulate phases.

Dust levels and control methods in poultry houses.

This article summarizes information from the papers and posters presented at the international symposium on "Dust Control in Animal Production Facilities", held in Aarhus (Denmark) on 30 May-2 June 1999. Dust concentrations in poultry houses vary from 0.02 to 81.33 mg/m3 for inhalable dust and from 0.01 to 6.5 mg/m3 for respirable dust. Houses with caged laying hens showed the lowest dust concentrations, i.e., less than 2 mg/m3, while the dust concentrations in the other housing systems, e.g., perchery and aviary systems, were often four to five times higher. Other factors affecting the dust concentrations are animal category, animal activity, bedding materials and season. The most important sources of dust seem to be the animals and their excrements. Further studies on the effects of housing systems on dust sources and their compounds are desired for development of a healthier working environment in poultry production facilities. Adjustment of the relative humidity (RH) of the air in a broiler house to 75% will have an effect on inhalable dust, but not on respirable dust. A slight immediate effect on the respirable dust was observed after fogging with pure water or water with rapeseed oil. In an aviary system, a 50 to 65% reduction of the inhalable dust concentration was found after spraying water with 10% of oil and pure water, respectively. To obtain a higher dust reducing efficiency, improvement of techniques for application of droplets onto dust sources will be desired.

A harness and computer system to facilitate automated body temperature data collection in heat-stressed broilers.

An easy-to-use, low-cost system was developed that permitted nearly continuous, automated core body temperature (Tc) readings on 7-wk-old male broiler chickens via direct computer linkage to thermistor probes held in place by a specially designed harness. Elevated Tc was noted in heat stress studies following the replacement of expelled temperature probes in some hyperthermic birds. To demonstrate the usefulness of the data collection system described herein, three treatments with three to four birds per treatment were used to examine this observation. Birds were designated as handled only (HAN), handled to remove and replace the temperature probe (RPL), or left as nonhandled controls (CON). Treatments had no effect on subsequent Tc in experiments when the thermoregulatory capacity of the birds was not challenged. However, when the birds were sufficiently challenged, Tc of HAN and RPL birds increased within 4 min of the initiation of handling and remained above baseline for up to 45 min. The Tc of CON birds in that trial also increased, but to a smaller degree, within 5 min and remained above baseline for up to 20 min. This study indicates that Tc of hyperthermic birds can be superelevated by simulated manual placement of cloacal temperature probes and that fixed probes connected to an automated data monitoring and collection system is a relatively simple way to avoid this problem.