Ammonia Concentrations and Emissions in Livestock Production Facilities: Guidelines and Limits in the USA and UK

There is much information about the concentrations and emissions of ammonia in livestock production facilities in Europe and North America; examples of best and worst practice have been identified in terms of building design and environmental management. Numerically, cattle are the largest source of ammonia emissions, while the ammonia concentration in swine and poultry buildings is much higher than in cattle sheds. In this paper, we review the grounds for concern over ammonia and question whether current guidelines and limits are sufficient to protect farmers, livestock and the environment. Firstly, epidemiological studies of worker health have shown that swine, and to a lesser extent, poultry workers experience occupational respiratory disease in which chronic ammonia exposure may play a part: current occupational exposure limits for ammonia are probably too high and should be revised downwards. Secondly, the scientific evidence that ammonia exposure affects animal health and performance is less convincing - though this is contrary to the empirical wisdom of veterinarians and farmers - and the guidelines are correspondingly unclear. A new guideline is provided from preference studies that show that pigs and chickens avoid ammonia concentrations above 10 ppm. Overall, only tentative guidelines for ammonia concentration can be proposed on the grounds of animal health, performance and welfare. Finally, as a result of international protocols, e.g. the UNECE convention on the long-range transport of air pollutants, individual countries are now expected to limit their ammonia emissions at a national level. This intention has not (yet) been translated into a specific limit on emission for individual farms. In the USA, but not UK, guidelines have also been suggested for ammonia concentration at the property line of animal feeding facilities

A mechanistic inter-species comparison of flicker sensitivity

AbstractThe general validity of both the Rovamo [Vision Res. 39 (1999) 533] and Barten (Contrast sensitivity of the human eye, SPIE Optical Engineering Press, 1999), modulation transfer function models for describing flicker sensitivity in vertebrates was examined using published data for goldfish, chickens, tree shrews, ground squirrels, cats, pigeons and humans. Both models adequately described the flicker response in each species at frequencies greater than approximately 1 Hz. At lower frequencies, response predictions differed between the two models and this was due, in part, to dissimilar definitions of the role played by lateral inhibition in the retina. Modelled flicker sensitivity for a matched retinal illuminance condition enabled a direct inter-species comparison of signal processing response times at the photoreceptor level. The modelled results also quantified differences between species in post-retinal signal processing capability. Finally, the relationship between flicker frequency response curves and the perception of temporal signals in real visual scenes was examined for each species. It is proposed that the area under the flicker sensitivity function may offer a single “figure of merit” for specifying overall sensitivity to time signals in a species’ environment

Tolerance of Atmospheric Ammonia by Laboratory Mice

A novel preference chamber with four inter-connected compartments was designed and built to test the tolerance of atmospheric ammonia by laboratory mice. The preference chamber incorporated a novel tracking system using an infra-red sensor at each end of each tunnel, which monitored all journeys through the tunnels and their direction. An experiment was successfully undertaken with four batches, each of four mice. Each batch was housed in the chamber for 4 days and given the choice between ammonia concentrations of nominally 0, 25, 50 and 100 ppm after initial familiarization. The results showed that there were two motivations acting on mouse behavior. The mice made extensive use of the whole chamber once they had been trained to use the tunnels, at least 2000 movements between compartments for each group over 48 h. The mice clearly preferred to be in the upper two compartments of the top tier of the chamber rather than in the lower compartments. The mice did not exhibit a clear preference for or aversion to ammonia, which implies that their short- term tolerance of ammonia at potentially noxious concentrations may not be in their long-term interest

Environmental impacts and sustainability of egg production systems

As part of a systemic assessment toward social sustainability of egg production, we have reviewed current knowledge about the environmental impacts of egg production systems and identified topics requiring further research. Currently, we know that 1) high-rise cage houses generally have poorer air quality and emit more ammonia than manure belt (MB) cage houses; 2) manure removal frequency in MB houses greatly affects ammonia emissions; 3) emissions from manure storage are largely affected by storage conditions, including ventilation rate, manure moisture content, air temperature, and stacking profile; 4) more baseline data on air emissions from high-rise and MB houses are being collected in the United States to complement earlier measurements; 5) noncage houses generally have poorer air quality (ammonia and dust levels) than cage houses; 6) noncage houses tend to be colder during cold weather due to a lower stocking density than caged houses, leading to greater feed and fuel energy use; 7) hens in noncage houses are less efficient in resource (feed, energy, and land) utilization, leading to a greater carbon footprint; 8) excessive application of hen manure to cropland can lead to nutrient runoff to water bodies; 9) hen manure on open (free) range may be subject to runoff during rainfall, although quantitative data are lacking; 10) mitigation technologies exist to reduce generation and emission of noxious gases and dust; however, work is needed to evaluate their economic feasibility and optimize design; and 11) dietary modification shows promise for mitigating emissions. Further research is needed on 1) indoor air quality, barn emissions, thermal conditions, and energy use in alternative hen housing systems (1-story floor, aviary, and enriched cage systems), along with conventional housing systems under different production conditions; 2) environmental footprint for different US egg production systems through life cycle assessment; 3) practical means to mitigate air emissions from different production systems; 4) process-based models for predicting air emissions and their fate; and 5) the interactions between air quality, housing system, worker health, and animal health and welfare

Neural Predictive Control of Broiler Chicken Growth

Active control of the growth of broiler chickens has potential benefits for farmers in terms of improved production efficiency, as well as for animal welfare in terms of improved leg health. In this work, a differential recurrent neural network (DRNN) was identified from experimental data to represent broiler chicken growth using a recently developed nonlinear system identification algorithm. The DRNN model was then used as the internal model for nonlinear model predicative control (NMPC) to achieve a group of desired growth curves. The experimental results demonstrated that the DRNN model captured the underlying dynamics of the broiler growth process reasonably well. The DRNN based NMPC was able to specify feed intakes in real time so that the broiler weights accurately followed the desired growth curves ranging from $-12$ to +12% of the standard curve. The overall mean relative error between the desired and achieved broiler weight was 1.8% for the period from day 12 to day 51

Estimation of the number and demographics of companion dogs in the UK

<p>Abstract</p> <p>Background</p> <p>Current estimates of the UK dog population vary, contain potential sources of bias and are based on expensive, large scale, public surveys. Here, we evaluate the potential of a variety of sources for estimation and monitoring of the companion dog population in the UK and associated demographic information. The sources considered were: a public survey; veterinary practices; pet insurance companies; micro-chip records; Kennel Club registrations; and the Pet Travel Scheme. The public survey and subpopulation estimates from veterinary practices, pet insurance companies and Kennel Club registrations, were combined to generate distinct estimates of the UK owned dog population using a Bayesian approach.</p> <p>Results</p> <p>We estimated there are 9.4 (95% CI: 8.1-11.5) million companion dogs in the UK according to the public survey alone, which is similar to other recent estimates. The population was judged to be over-estimated by combining the public and veterinary surveys (16.4, 95% CI: 12.5-21.5 million) and under-estimated by combining the public survey and insured dog numbers (4.8, 95% CI: 3.6-6.9 million). An estimate based on combining the public survey and Kennel Club registered dogs was 7.1 (95% CI: 4.5-12.9) million. Based on Bayesian estimations, 77 (95% CI: 62-92)% of the UK dog population were registered at a veterinary practice; 42 (95% CI: 29-55)% of dogs were insured; and 29 (95% CI: 17-43)% of dogs were Kennel Club registered. Breed demographics suggested the Labrador was consistently the most popular breed registered in micro-chip records, with the Kennel Club and with J. Sainsbury's PLC pet insurance. A comparison of the demographics between these sources suggested that popular working breeds were under-represented and certain toy, utility and miniature breeds were over- represented in the Kennel Club registrations. Density maps were produced from micro-chip records based on the geographical distribution of dogs.</p> <p>Conclusions</p> <p>A list containing the breed of each insured dog was provided by J. Sainsbury's PLC pet insurance without any accompanying information about the dog or owner.</p

Neural predictive control of broiler chicken and pig growth

Active control of the growth of broiler chickens and pigs has potential benefits for farmers in terms of improved production efficiency, as well as for animal welfare in terms of improved leg health in broiler chickens. In this work, a differential recurrent neural network (DRNN) was identified from experimental data to represent animal growth using a nonlinear system identification algorithm. The DRNN model was then used as the internal model for nonlinear model predictive control (NMPC) to achieve a group of desired growth curves. The experimental results demonstrated that the DRNN model captured the underlying dynamics of the broiler and pig growth process reasonably well. The DRNN based NMPC was able to specify feed intakes in real time so that the broiler and pig weights accurately followed the desired growth curves ranging from to +12% and to +20% of the standard curve for broiler chickens and pigs, respectively. The overall mean relative error between the desired and achieved broiler or pig weight was 1.8% for the period from day 12 to day 51 and 10.5% for the period from week 5 to week 21, respectively

Ammonia Concentrations and Emissions in Livestock Production Facilities: Guidelines and Limits in the USA and UK

There is much information about the concentrations and emissions of ammonia in livestock production facilities in Europe and North America; examples of best and worst practice have been identified in terms of building design and environmental management. Numerically, cattle are the largest source of ammonia emissions, while the ammonia concentration in swine and poultry buildings is much higher than in cattle sheds. In this paper, we review the grounds for concern over ammonia and question whether current guidelines and limits are sufficient to protect farmers, livestock and the environment. Firstly, epidemiological studies of worker health have shown that swine, and to a lesser extent, poultry workers experience occupational respiratory disease in which chronic ammonia exposure may play a part: current occupational exposure limits for ammonia are probably too high and should be revised downwards. Secondly, the scientific evidence that ammonia exposure affects animal health and performance is less convincing - though this is contrary to the empirical wisdom of veterinarians and farmers - and the guidelines are correspondingly unclear. A new guideline is provided from preference studies that show that pigs and chickens avoid ammonia concentrations above 10 ppm. Overall, only tentative guidelines for ammonia concentration can be proposed on the grounds of animal health, performance and welfare. Finally, as a result of international protocols, e.g. the UNECE convention on the long-range transport of air pollutants, individual countries are now expected to limit their ammonia emissions at a national level. This intention has not (yet) been translated into a specific limit on emission for individual farms. In the USA, but not UK, guidelines have also been suggested for ammonia concentration at the property line of animal feeding facilities.This is an ASAE Meeting Presentation, Paper No. 034112.</p