Ventilation rates in large commercial layer hen houses with two-year continuous monitoring.

1. Ventilation controls the indoor environment and is critical for poultry production and welfare. Ventilation is also crucial for assessing aerial pollutant emissions from the poultry industry. Published ventilation data for commercial layer houses have been limited, and are mostly based on short-term studies, mainly because monitoring airflow from large numbers of fans is technically challenging. 2. A two-year continuous ventilation monitoring trial was conducted at two commercial manure belt houses (A and B), each with 250 000 layers and 88 130-cm exhaust fans. All the fans were individually monitored with fan rotational speed sensors or vibration sensors. Differential static pressures across the house walls were also measured. Three fan performance assessment methods were applied periodically to determine fan degradations. Fan models were developed to calculate house ventilations. 3. A total of 693 and 678 complete data days, each containing >16 h of valid ventilation data, were obtained in houses A and B, respectively. The two-year mean ventilation rates of houses A and B were 2·08 and 2·10 m(3) h(-1) hen(-1), corresponding to static pressures of -36·5 and -48·9 Pa, respectively. For monthly mean ventilation, the maximum rates were 4·87 and 5·01 m(3) h(-1) hen(-1) in July 2008, and the minimum were 0·59 and 0·81 m(3) h(-1) hen(-1) in February 2008, for houses A and B, respectively. 4. The two-year mean ventilation rates were similar to those from a survey in Germany and a 6-month study in Indiana, USA, but were much lower than the 8·4 and 6·2 m(3) h(-1) hen(-1) from a study in Italy. The minimum monthly mean ventilation rates were similar to the data obtained in winter in Canada, but were lower than the minimum ventilation suggested in the literature. The lower static pressure in house B required more ventilation energy input. The two houses, although identical, demonstrated differences in indoor environment controls that represented potential to increase ventilation energy efficiency, and reduce carbon footprints and operational costs.

Characteristics of ammonia and carbon dioxide releases from layer hen manure.

1. Ammonia (NH(3)) is an important gaseous pollutant generated from manure in commercial poultry farms and has been an environmental, ecological, and health concern. Poultry manure also releases carbon dioxide (CO(2)), which is a greenhouse gas and is often used as a tracer gas to calculate building ventilation. 2. A 38-d laboratory study was conducted to evaluate the characteristics of NH(3) and CO(2) releases from layer hen manure using 4 manure reactors (122 cm tall, 38 cm internal diameter), which were initially filled with 66 cm deep manure followed by weekly additions of 5 cm to simulate manure accumulation in commercial layer houses. 3. The average daily mean (ADM) NH(3) and CO(2) release fluxes for the 4 reactors during the entire study were 1615 +/- 211 microg/s.m(2) (ADM +/- 95% confidence interval) and 100 +/- 03 mg/s.m(2), respectively. The daily mean NH(3) and CO(2) releases in individual reactors varied from 352 to 6791 microg/s.m(2) and from 66 to 205 mg/s.m(2), respectively. 4. The ADM NH(3) release flux was within the range of those obtained in 4 high-rise layer houses by Liang et al. (2005, Transactions of the ASAE, 48). However, the CO(2) release flux in this study was about 10 to 13 times as high as the data reported by Liang et al. (2005). Fresh manure had greater NH(3) release potential than the manure in the reactors under continuous ventilation. Manure with higher contents of moisture, total nitrogen, and ammonium in the 4th weekly addition induced 11 times higher NH(3) and 75% higher CO(2) releases immediately after manure addition compared with pre-addition releases.

Iohexol: a new, nonionic agent in adult peripheral arteriography.

The safety and efficacy of iohexol, a new nonionic contrast agent, were compared with a diatrizoate (Renografin-76) in a double-blind, parallel study of peripheral arteriography by femoral puncture in 60 patients. Extra-large field serial peripheral arteriography was used and a posterior tibial nerve block was applied to all patients in the study. Similar changes in blood chemistry were observed following the injection of iohexol and diatrizoate but these changes did not require corrective measures. Significantly more patients complained of a sensation of severe heat after receiving diatrizoate (38%) than after the injection of iohexol (10%) (p = 0.001). Four patients in the diatrizoate group experienced one or more adverse reactions, including mild urticaria. Only mild nausea was reported by a single patient in the iohexol group. Overall, 100% of the studies were diagnostic but more of the radiographs taken after the injection of iohexol were rated excellent than after the injection of diatrizoate.