Comparative performance of three sampling techniques to detect airborne Salmonella species in poultry farms

Sampling techniques to detect airborne Salmonella species (spp.) in two pilot scale broiler houses were compared. Broilers were inoculated at seven days of age with a marked strain of Salmonella enteritidis. The rearing cycle lasted 42 days during the summer. Airborne Salmonella spp. were sampled weekly using impaction, gravitational settling, and impingement techniques. Additionally,Salmonella spp. were sampled on feeders, drinkers, walls, and in the litter. Environmental conditions (temperature, relative humidity, and airborne particulate matter (PM) concentration) were monitored during the rearing cycle. The presence of Salmonella spp. was determined by culture-dependent and molecular methods. No cultivable Salmonella spp. were recovered from the poultry houses' surfaces, the litter, or the air before inoculation. After inoculation, cultivable Salmonella spp. were recovered from the surfaces and in the litter. Airborne cultivable Salmonella spp. were detected using impaction and gravitational settling one or two weeks after the detection of Salmonella spp. in the litter. No cultivable Salmonella spp. were recovered using impingement based on culture-dependent techniques. At low airborne concentrations, the use of impingement for the quantification or detection of cultivable airborne Salmonella spp. is not recommended. In these cases, a combination of culture-dependent and culture-independent methods is recommended. These data are valuable to improve current measures to control the transmission of pathogens in livestock environments and for optimising the sampling and detection of airborne Salmonella spp. in practical conditions.The research was funded by the Spanish Ministry of Science and Innovation (Project No. GASFARM-2 AGL2008-04125, Madrid). The authors express their thanks to the Centro de Tecnologia Animal (IVIA, Spain) and its staff for providing the broiler installations and collaborating during this study. We are also grateful to the Livestock Research Group of Wageningen UR, The Netherlands, for their equipment support. The authors also wish to thank the Campus de Excelencia Internacional of the Universitat Politecnica de Valencia, Spain.Adell Sales, E.; Moset, V.; Zhao, Y.; Jiménez Belenguer, AI.; Cerisuelo, A.; Cambra López, M. (2014). Comparative performance of three sampling techniques to detect airborne Salmonella species in poultry farms. Annals of Agricultural and Environmental Medicine. 21(1):15-24. http://hdl.handle.net/10251/64122S152421

Modelling methane emission mitigation by anaerobic digestion: effect of storage conditions and co-digestion

<p>In this work the methane conversion factor (MCF) of untreated and anaerobically digested cattle manure (CM) as a function of storage temperature, time and co-digestion was measured in an in vitro experiment and modelled based on IPCC (2006) methodology (Tier 2). For this, one sample of untreated CM, one sample of mono-digested CM and three samples of CM co-digested with grass were incubated at seven different temperatures (from 5°C to 50°C) over 346 days. The main results showed that ultimate methane yield (<i>B</i>₀) of CM is higher than the <i>B</i>₀ reported by the IPCC (2006). Two temperature ranges should be considered for MCF evolution, below 15°C very low MCF was measured in this work for untreated CM, mono and co-digested samples. At higher temperatures, MCF obtained in this work and that provided by the IPCC could be comparable depending on storage time. Anaerobic mono-digestion decreased MCF compared to untreated CM at all temperatures and times, except in the temperature range between 20°C and 25°C if storage time is low, due to a lag phase observed in CM. This lag phase would probably not happen in real storage conditions depending on the proportion of old manure remaining in the storage tank. Co-digestion with grass-decreased MCF compared to mono-digestion, but increased CH₄ production in terms of fresh matter due to the higher <i>B</i>₀ of the mixture. Storage time, temperature and co-digestion should be considered in the quantification of CH₄ emission from digested material.</p

A dynamic model of ammonia emission and concentration in fattening pig buildings

The control of gas emissions from livestock buildings, especially ammonia, is important to limit the environmental impact, which depends primarily on the cumulated emission, and to improve the welfare and health of the animals and the stockmen, are affected by gas concentration inside the building. The model developed in this work aims at integrating the information and models already available in the literature in order to predict the ammonia emission and concentration inside the fattening rooms and in the exhausted air. The model includes the description of animals and feeding, housing and indoor climate, and processes involved in ammonia emission. Different housing designs are considered in the model including different types of slatted floors and ventilation systems. The effect of outdoor climate, including seasonal and diurnal variations, is also taken into account. The model predicts the indoor climate and the emission and concentration of ammonia. A sensitivity analysis has been performed in order to evaluate the effects of season, type of ventilation, and type and cleanliness of floor. These simulations indicated that ammonia emission and concentration are not well correlated and are highly dependant on the ventilation system and the temperature. The model was validated by comparison with ammonia concentration available from the literature, with different types of ventilation and slatted floor, and different indoor temperatures