Cost effective combined axial fan and throttling valve control of ventilation rate

This paper is concerned with Proportional-Integral-Plus (PIP) control of ventilation rate in mechanically ventilated agricultural buildings. In particular, it develops a unique fan and throttling valve control system for a 22m3 test chamber, representing a section of a livestock building or glasshouse, at the Katholieke Universiteit Leuven. Here, the throttling valve is employed to restrict airflow at the outlet, so generating a higher static pressure difference over the control fan. In contrast with previous approaches, however, the throttling valve is directly employed as a second control actuator, utilising airflow from either the axial fan or natural ventilation. The new combined fan/valve configuration is compared with a commercially available PID-based controller and a previously developed scheduled PIP design, yielding a reduction in power consumption in both cases of up to 45%

Frequency analysis of vocalisations in relation to the growth in broiler chicken

Poultry is one of the lowest cost sources of animal protein in the world and, more than 40 billion chickens are produced every year globally. For reasons of public concern and due to the large number of animals involved, it is considered by many people to be important to take care of the welfare and health status of the chickens reared under intensive farm conditions. Precision Livestock Farming (PLF) can support the farmer in his day to day routine management through the use of sensors, cameras and microphones, and these have the potential to improve production and to enable monitoring of welfare status. In this context, the 7FP EU-PLF project aims to test the efficiency of the use of those sensors at farm level. In particular, the aim of this study was to record and analyse broiler vocalisations under normal farm conditions and to identify the relation between animal sounds, and growth trends. Recordings were made at regular intervals, for the entire short production life of the birds, in order to evaluate the variation of frequency and bandwidth of the sounds emitted by the animals during the cycle of production. The recordings were made in an automated, non-invasive and non-intrusive way and the sound data was compared with the weight of the birds automatically measured by a 'step on scale' placed on the floor of the broiler house. Sound analysis was performed based on the amplitude and frequency of the sound signal in audio files recorded at farm level. Through analysis of the sounds recorded, a significant correlation (P<0.001) between the frequencies of the vocalisations recorded and the weight of the broilers was found across all production cycles and farms assessed. The ongoing goal will be the development of a tool able to automatically detect the growth of the animals based on the frequency of the vocalisation emitted by the birds at different ages, and as a possible tool for determining deviations from their expected growth trend

Risk factor for footpad dermatitis and hock burns in broiler chickens

Footpad dermatitis (FPD) and hock burn (HB) are a major welfare concern in broiler chicken farming. In general, foot lesions are linked to poor environmental conditions. Ulcers caused by advanced lesions can negatively affect the gait of the birds, with effects on the welfare of animals, including, in the worst cases, inability to reach the feed or water. FPD and HB score data were collected manually at two broiler farms across Europe, during welfare assessments performed within the EU-PLF (Precision Livestock Farming) project, which is supported by the European Commission. This ongoing project aims to create "added value" for the farmer through the application of sensors and information technology at farm level. On those broiler farms, a number of variables such as temperature, relative humidity, ventilation rate, bird weight, light schedule, and feed and water consumption rates are measured automatically. The welfare of the chickens was assessed three times per cycle (at week 3, 4 and 5), scoring FPD, HB, gait score, cleanliness of the birds and litter quality. Data analysis was performed by combining data from the welfare assessments with environmental data collected by the automatic monitoring systems. The analysis showed that FPD and HB were more frequent when the flock was exposed to poor environmental conditions for prolonged periods of time. As environmental conditions can be measured continuously, and the risk factor for FPD and HB increases with poor environmental conditions, there is potential to develop a detection and control system for foot and hock lesions.</p

Real-time modelling of indoor particulate matter concentration in poultry houses using broiler activity and ventilation rate

Measuring particulate matter concentration in poultry houses remains as a difficult task, primarily because aerosol analysers are expensive, require specialist knowledge to operate and are labour intensive to maintain. However, it is well known that high concentrations of particulate matter causes health and welfare problems with livestock, farm workers and people living in the vicinity of the farm premises. In this work, a data-based mechanistic model is developed to relate broiler activity and ventilation rate with indoor particulate matter concentration. For six complete growing cycles, in a U.K. commercial poultry farm, broiler activity was monitored using a camera-based flock monitoring system (eYeNamic®) and ventilation rate was measured. Indoor particulate matter concentration was continuously monitored by measuring size-segregated mass fraction concentrations with the aerosol analyser DustTrakTM. A discrete-time multi-input single-output time-invariant parameters Transfer Function model was developed to determine the particulate dynamics within each day of the growing cycle in the poultry house using broiler activity and ventilation rate as inputs. This model monitored indoor particulate matter concentration with an average accuracy of RT2=(51±26)%. A dynamic linear regression modelling with time-variant parameters improved average accuracy with RT2=(97.7±1.3)%. It forecasted one sample-ahead the indoor particulate matter concentration level, using a time window of 14 samples, with a mean relative prediction error, MRPE=(4.6±3.2)%. Thus, dynamic modelling with time-variant parameters has the potential to be part of a control system to manage in real-time indoor particulate matter concentration in broiler houses.status: publishe

European farmers&apos; experiences with precision livestock farming systems

In the public debate about modern animal production methods, the voice of the farmer is rarely heard. Little is known about the daily work and economic pressure the single farmer is exposed to and what he thinks and feels about the increasingly complex production systems with demanding new control and monitoring technologies such as PLF. In a limited survey based on 21 farm visits (nine pig, five broiler, and seven dairy farms) in 10 EU countries, the knowledge of farmers on options and opportunities of precision livestock farming (PLF) technologies in modern animal production systems was investigated. The farmers were asked by personal free-format interviews face to face on their farms. Most pig and poultry farms were visited in 2014, just after the installation of the PLF technology in the farms and 2016 again after 2 yr of experience. The dairy farms could be visited only once in 2016. All farmers who get sufficient support from the providers developed a positive to very positive attitude to the real-time monitoring PLF systems. This applies for pig, broiler, and cow farms. Broiler farmers were more open to PLF than pig farmers. All farmers emphasized with few exceptions that the personal contact to the animals cannot be replaced by video cameras, but the PLF systems can be of great help in daily life. They enable the farmer to recognize problems significantly earlier than with conventional methods. These techniques are not only helpful and animal friendly, they may also assist to bridge the presently existing gap between producers and consumers by transparency of production. Drawbacks are the relative high prices for PLF equipment, sometimes poor maintenance service by the delivering companies, and the lack of broader experience with the systems in practice. Although one farmer responded after 2 yr of experience with his PLF system that he would not miss it anymore and that he understands his animals much better since he uses PLF monitoring, there is an urgent need for more and wider experiences. It is recommended to further test and develop PLF technologies in demonstration farms under practical conditions. It seems that PLF technologies can play an important role in the development of a future-oriented, sustainable, animal-friendly, and efficient livestock production with healthy animals

Intergrading reef communities across discrete seaweed habitats in a temperate–tropical transition zone:Lessons for species reshuffling in a warming ocean

Temperate reefs are increasingly affected by the direct and indirect effects of climate change. At many of their warm range edges, cool‐water kelps are decreasing, while seaweeds with warm‐water affinities are increasing. These habitat‐forming species provide different ecological functions, and shifts to warm‐affinity seaweeds are expected to modify the structure of associated communities. Predicting the nature of such shifts at the ecosystem level is, however, challenging, as they often occur gradually over large geographical areas. Here, we take advantage of a climatic transition zone, where cool‐affinity (kelp) and warm‐affinity (Sargassum) seaweed forests occur adjacently under similar environmental conditions, to test whether these seaweed habitats support different associated seaweed, invertebrate, coral, and fish assemblages. We found clear differences in associated seaweed assemblages between habitats characterized by kelp and Sargassum abundance, with kelp having higher biomass and seaweed diversity and more cool‐affinity species than Sargassum habitats. The multivariate invertebrate and fish assemblages were not different between habitats, despite a higher diversity of fish species in the Sargassum habitat. No pattern in temperature affinity of the invertebrate or fish assemblages in each habitat was found, and few fish species were exclusive to one habitat or the other. These findings suggest that, as ocean warming continues to replace kelps with Sargassum, the abundance and diversity of associated seaweeds could decrease, whereas fish could increase. Nevertheless, the more tropicalized seaweed habitats may provide a degree of functional redundancy to associated fauna in temperate seaweed habitats

Waterverdamping uit dunne mest met behulp van ventilatielucht

De warmte in de uitgaande ventilatielucht kan worden gebruikt om water te verdampen uit mest. Met een simulatiemodel is berekend hoeveel water op deze manier verdampt kan worden