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

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

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

Exposure to environmental stressors result in increased viral load and further reduction of production parameters in pigs experimentally infected with PCV2b

Porcine circovirus type 2 (PCV2) has been identified as the essential, but not sole, underlying infectious component for PCV-associated diseases (PCVAD). Several co-factors have been suggested to convert an infection with PCV2 into the clinical signs of PCVAD, including co-infection with a secondary pathogen and the genetic background of the pig. In the present study, we investigated the role of environmental stressors in the form of changes in environmental temperature and increased stocking-density on viral load in serum and tissue, average daily weight gain (ADG) and food conversion rate (FCR) of pigs experimentally infected with a defined PCV2b strain over an eight week period. These stressors were identified recently as risk factors leading to the occurrence of severe PCVAD on a farm level. In the current study, PCV2-free pigs were housed in separate, environmentally controlled rooms, and the experiment was performed in a 2 × 2 factorial design. In general, PCV2b infection reduced ADG and increased FCR, and these were further impacted on by the environmental stressors. Furthermore, all stressors led to an increased viral load in serum and tissue as assessed by qPCR, although levels did not reach statistical significance. Our data suggest that there is no need for an additional pathogen to develop PCVAD in conventional status pigs, and growth retardation and clinical signs can be induced in PCV2 infected pigs that are exposed to environmental stressors alone

The effect of a photoperiodic green light program during incubation on embryo development and hatch process

This study was conducted to evaluate the effect of a 12 hours light, 12 hours dark  (12L:12D) photoperiod of green light during day 1 to day 18 of incubation time, on embryo growth, hatch performance and the hatch process. In the light-stimulated group, the monochromatic light was provided by a total of 204 green LEDs (522nm) mounted in a frame which was placed above the eggs to give even spread of illumination. The control group was incubated in complete darkness. Four batches of eggs (n=300 per group per batch) from fertile Ross 308 broiler breeders were used in this experiment.  The beak length and crown-rump length compared of embryos incubated under green light were significantly longer than those incubated in the dark condition at day10and day 12, respectively (P<0.01). Furthermore, green light exposed embryos had a longer third toe length compared to control embryos at day 10, day14 and day17 (P=0.02).  At the group level (n=4 batches), light stimulation had no effect on chick weight and quality at take-off, the initiation of hatch and hatch window. However the individual hatching time of the light stimulated focal chicks (n=33) was 3.4h earlier (P=0.49) than then control focal chicks (n=36). The results of this study indicated that green light accelerated embryos development and resulted in an earlier hatching

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

Modelling bio-aerosol concentration in commercial poultry houses

Measuring bio-aerosol concentration in poultry houses remains as a difficult task. Aerosol analyzers are expensive and require frequent labor intensive maintenance. Precision Livestock Farming technologies support farmers in their daily routine of animal management, through monitoring animals continuously during their life in an automated, non-invasive way, without inducing additional stress in the animals. In this work, a model to relate broiler activity and ventilation rate with aerosol concentration has been developed. For several complete growing periods in a UK commercial poultry farm, broiler activity using the eYeNamic® system and ventilation rate using the climate control system were measured. Bio-aerosol concentration was continuously monitored using DustTrakTM and the Aerosol Particle Sizer analyzers, to be used as Gold Standards. A Multi-Input Single-Output Transfer Function model was developed to estimate the aerosol concentration in the poultry house using broiler activity and ventilation rate as inputs. This model has an average accuracy of 82%. This model has the potential, not only to continuously estimate the aerosol concentration in the poultry house by automated monitoring of broiler activity and ventilation rate, but also to be part of a control system to manage aerosol concentration in the farm in real-time.status: publishe

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.This is an ASAE Meeting Presentation, Paper No. 064017.</p