Effects of dietary ingredients on manure characteristics and odorous emissions from swine.

Two feeding studies were conducted to examine the impact of dietary inclusion of specific feed ingredients on manure characteristics and manure odor. In one study, 72 finishing pigs were used to evaluate the effects of distillers dried grains with solubles (DDGS) on pig performance, manure characteristics, and odorous emissions. Three diets containing 0, 5, and 10% DDGS were fed during six 4-wk feeding periods. Week 1 served as a dietary adjustment period. Animals were housed in two feeding rooms (six pigs/room) with one treatment/room. A new group of animals (average initial BW = 85.8 kg) was used for each feeding period. Diets were replicated four times. Rooms were equipped with individual shallow manure storage pits that were cleaned once weekly (d 7). On d 4 and 7 of each week, manure pit samples, for chemical analyses, and air samples, for olfactometry analysis, were collected from each room. Odor dilution threshold was greater on d 7 than on d 4 of manure storage across all treatments (P < 0.01). No treatment differences in manure composition were noted. In the second study, weaned pigs (approximately 5 wk old) were fed isonitrogenous diets containing 0, 1.5, or 3% bloodmeal. Pigs were housed by diet (three pigs/diet) in one of four individual feeding rooms. A new group of pigs was used for each of the two, 4-wk feeding periods. During period 1, the 3% bloodmeal diet was fed in two of the four rooms; the 0% bloodmeal diet was fed in two rooms during period 2. Manure samples, for chemical analyses, and air samples, for olfactometry analysis, were collected 2 d per week (d 4 and d 6) from each room during wk 2 through 4. No significant treatment differences were observed for odor dilution threshold (P = 0.30). Longer manure storage time, 6 d vs 4 d, resulted in a larger odor dilution ratio (P < 0.01). Manure composition was unaltered by storage time. Results suggest that odor intensifies during storage.

Using olfactometry to measure intensity and threshold dilution ratio for evaluating swine odor.

Intensity and threshold dilution ratio are two important indices for odor control of swine buildings. Although odor threshold dilution ratio is a widely used index to describe an odor, it should be related to intensity to be more useful. A method was proposed to measure both indices simultaneously by using a dynamic forced-choice olfactometer. Four air samples were taken from each of four swine rooms including farrowing, finisher, gestation, and nursery. A panel of eight people was used to evaluate odor intensity. Odor threshold dilution ratios were calculated according to the American Society for Testing and Materials (ASTM) Standard Practice E679-91 to be 333, 424, 25, and 221 for samples collected from farrowing, finisher, gestation, and nursery rooms, respectively. After the samples were diluted 14.7 times, the odor intensities were evaluated to be 3.79, 3.46, 0.48, and 4.0 for the above-mentioned rooms, respectively. The data collected were used to develop a mathematical model.

Quantification of ventilation on distribution of gaseous pollutants emitted from stored swine manure.

This paper describes the quantification of the effects of ventilation on distribution of gaseous pollutants as a result of mass transfer from stored manure to ventilation air in a swine confinement building. A multiple airflow regions model is developed and used to simulate the dynamics of gaseous pollutants in any airspace within a ventilated slotted-inlet enclosure. The model predictions compared favorably with the measured results adapted from a literature research at ventilation rates between 443 and 932 m3/hr (deviations of 5.1-14.68%) for carbon dioxide and ammonia concentrations. A comparison between predictions and measured carbon dioxide concentrations derived from an environmental chamber test found deviations ranged from 3.1-5.6% at ventilation rates between 281 and 995 m3/hr. The results suggest that the model can be experimentally applied between ventilation rates of 443 and 995 m3/hr. The model also capable of predicting air exchange rate required to maintain acceptable levels of gaseous pollutants in swine confinement buildings based on gas emission rates.

Effect of environmental variables in turkey confinement houses on airborne Aspergillus and mycoflora composition.

Environmental conditions and airborne mycoflora were measured concurrently in 10 turkey confinement houses during warm and cold weather. The following variables in the environment were measured: numbers of feed- and litter-associated yeast and mold fungi, temperature, relative humidity, airspeed, carbon dioxide and ammonia concentration, airborne bacteria, and airborne particulate mass, particle number, and particle size distribution. Winter air in turkey confinement houses contained significantly higher concentrations of Aspergillus, Scopulariopsis, and Mucor sp. and significantly lower concentrations of Cladosporium, Fusarium, and Alternaria sp. when compared with summer air. Significantly greater numbers of Mucor sp. were recovered per cubic meter of air where the current turkey flock was present less than 100 d when compared to houses where the current flock resided 100 d or more. Management decisions regarding control of the internal environment of turkey confinement houses apparently influence airborne mycoflora composition.

Effect of building ventilation design on environment and performance of turkeys.

Environmental variables in 10 commercial turkey confinement buildings, representing 2 natural ventilation designs, were measured during summer and the following winter. Sliding doors spaced at intervals along the walls of 5 of the buildings provided about 35% opening, and continuous wall curtains provided 60 to 80% opening in the other 5 buildings. Environmental variables assessed included airspeed; temperature; relative humidity; gases; particle number, size, and mass per cubic meter of air; and colonies of bacteria, yeasts, and other fungi per cubic meter of air. Colonies of yeasts and other fungi were quantitated in feed and litter. For most of the variables evaluated, significant differences were not attributable to building ventilation design; however, in winter, the total mass of particulate matter per cubic meter of air was higher in the curtain-type houses, compared with sliding door-type houses. Ammonia concentration in the air of sliding door-type houses progressively increased during summer and winter sampling periods. A significant effect of building ventilation design on turkey performance was not detected when using mortality, average daily gain, feed conversion, condemnations at slaughter, or average individual bird weight as measures of production.