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Biomedical subjects

D Berckmans

Publications and source records attributed to D Berckmans.

16 recordsLinked to original sources
PubMed2006

End-weight prediction in broiler growth.

1. Two different methods, categorised as input-output and single output models, were evaluated for slaughter weight prediction of broiler chickens. The input-output models included linear and non-linear recursive modelling with a time-varying model structure, whereas the output models consisted only of empirical growth equations and several growth curve fitting techniques. 2. The results suggested that a simple linear growth curve fitting method gives the greatest accuracy in a prediction horizon of 4 d or less. Error is minimised to an average of 0.14% when 4 d of past information is used to fit a line to predict the end weight one day ahead.

Animals↗
PubMed2005

Design of laying nests in furnished cages: influence of nesting material, nest box position and seclusion.

(1) Preferences for three nesting materials and nest box positions were investigated simultaneously in two trials using a furnished cage: one with 18 individual laying hens and one with 18 groups of 5 hens. Following a habituation period in pre-test cages, every hen or group of hens was tested for 2 d: once without and once with plastic flaps at the entrance of the nest boxes. (2) Hens preferred peat and artificial turf to coated wire mesh for egg laying. (3) One nest box position was clearly preferred to both other nest boxes. The hens' choice of nest box position was influenced by the pre-test cage in which they had been habituated. (4) The presence of plastic flaps at the entrance of the nest boxes had no influence on the proportion of eggs laid on the different nesting materials or on the proportion of floor eggs. (5) Individual and group testing resulted in the same overall results despite the presence of a distinct group effect.

Animal Husbandry↗
PubMed2005

Quantification of the heat exchange of chicken eggs.

In the incubation process of domestic avian eggs, the development of the embryo is mainly influenced by the physical microenvironment around the egg. Only small spatiotemporal deviations in the optimal incubator air temperature are allowed to optimize hatchability and hatchling quality. The temperature of the embryo depends on 3 factors: (1) the air temperature, (2) the exchange of heat between the egg and its microenvironment and (3) the time-variable heat production of the embryo. Theoretical estimates on the heat exchange between an egg and its physical microenvironment are approximated using equations that assume an approximate spherical shape for eggs. The objective of this research was to determine the heat transfer between the eggshell and its microenvironment and then compare this value to various theoretical estimates. By using experimental data, the overall and the convective heat transfer coefficients were determined as a function of heat production, air humidity, air speed, and air temperature. Heat transfer was not affected by air humidity but solely by air temperature, embryonic heat generation, and air speed and flow around eggs. Also, heat transfer in forced-air incubators occurs mainly by convective heat loss, which is dependent on the speed of airflow. A vertical airflow is more efficient than a horizontal airflow in transferring heat from the egg. We showed that describing an egg as a sphere underestimated convective heat transfer by 33% and was, therefore, too simplistic to accurately assess actual heat transfer from real eggs.

Air Movements↗
PubMed2004

Objective recognition of cough sound as biomarker for aerial pollutants.

A relationship among air quality, respiratory health, and comfort in man and animal is widely shown. In general, a state of respiratory discomfort is prevailed by an increase in acoustic audible symptoms. The general concept of sound analysis as an objective contactless non-invasive biomarker for aerial pollution is studied on free-field cough sound of 12 Belgian Landrace piglets. A citric-acid-induced cough sound recognition algorithm with recognition rate of 95% is applied to cough sounds registered in the presence of distinct types of aerial pollutants: irritating gas (ammonia), respirable particles (dust), and temperature. The recognition performance for all aerial pollutants was >90% and maintained 94% on average. It is concluded that sound analysis allows an effective biomarker for all three types of aerial pollution. The generality of the biomarker is hypothesized to be due to the common mechanism involved in protective cough. As a consequence, it is suggested to use sound analysis as a biomarker for respiratory state in studies of exposure to air pollutants.

Air Pollutants↗
PubMed2004

Modeling the internal dynamics of energy and mass transfer in an imperfectly mixed ventilated airspace.

UNLABELLED: The present paper outlines a modeling approach, which has been developed to model the internal dynamics of heat and moisture transfer in an imperfectly mixed ventilated airspace. The modeling approach, which combines the classical heat and moisture balance differential equations with the use of experimental time-series data, provides a physically meaningful description of the process and is very useful for model-based control purposes. The paper illustrates how the modeling approach has been applied to a ventilated laboratory test room with internal heat and moisture production. The results are evaluated and some valuable suggestions for future research are forwarded. PRACTICAL IMPLICATIONS: The modeling approach outlined in this study provides an ideal form for advanced model-based control system design. The relatively low number of parameters makes it well suited for model-based control purposes, as a limited number of identification experiments is sufficient to determine these parameters. The model concept provides information about the air quality and airflow pattern in an arbitrary building. By using this model as a simulation tool, the indoor air quality and airflow pattern can be optimized.

Air Movements↗
PubMed2003

Computer-assisted image analysis to quantify daily growth rates of broiler chickens.

1. The objective was to investigate the possibility of detecting daily body weight changes of broiler chickens with computer-assisted image analysis. 2. The experiment included 50 broiler chickens reared under commercial conditions. Ten out of 50 chickens were randomly selected and video recorded (upper view) 18 times during the 42-d growing period. The number of surface and periphery pixels from the images was used to derive a relationship between body dimension and live weight. 3. The relative error in weight estimation, expressed in terms of the standard deviation of the residuals from image surface data was 10%, while it was found to be 15% for the image periphery data. 4. Image-processing systems could be developed to assist the farmer in making important management and marketing decisions.

Animals↗
PubMed2003

Do heavy broiler chickens visit automatic weighing systems less than lighter birds?

1. In previous studies it was found that automatic broiler weighing systems can have accuracy problems. Researchers reported poor agreement between automatic and manual mean weighing used as a reference. The difference was observed especially after 4 to 5 weeks and this was explained by assuming that heavier birds visited the weighing system less at the end of the growing period. 2. Our study tested this hypothesis under practical production conditions. 3. In total, 193,536 digital images of broilers on and in the neighbourhood of the platforms were collected over three growing periods of 6 weeks. The area (upper view) of the broilers was calculated using image analysis techniques. 4. The hypothesis that the weighing system was used less frequently by heavier animals was confirmed. More specifically, statistical differences between the area of broilers on and in the neighbourhood of the weighing system could be demonstrated for week 5.

Animals↗
PubMed2003

Recursive prediction of broiler growth response to feed intake by using a time-variant parameter estimation method.

The objective of this study was to explore whether time-variant parameter estimation procedures allow modeling and predicting the dynamic growth response of broiler chickens to feed intake in real time. A recursive linear model was used that estimated the model parameters every 24 h based on a fixed number of actual and past measurements (i.e., time window). Based on 48 datasets, it was concluded that the mean relative prediction error (MRPE) of the recursive linear modeling approach had a minimum for a window size of 5 d. Weight of the birds could be predicted during the growth process 3 to 7 d ahead with a mean relative prediction error of 5% or less. In comparison with the prediction results of three static empirical growth models (one linear and two nonlinear models), the recursive modeling technique had a similar accuracy to the nonlinear empirical models (MRPE of 1.4% to 2.3% vs. 1.1% to 2.8%), but it was less accurate for larger prediction horizons (2 to 7 d). The compact recursive linear model was more accurate than the static linear growth model for prediction horizons of one up to 4 d, depending on the feeding strategy. Since such recursive modeling approach allows the prediction of broiler growth without any prior knowledge of the system and takes into account the time-variant (nonlinear) nature of the growth process based on only a small window of measured information, it is suitable for real-time integration in process management.

Animal Nutritional Physiological Phenomena↗
PubMed2003

Quantification and control of the spatiotemporal gradients of air speed and air temperature in an incubator.

Around the optimal incubator air temperature only small spatiotemporal deviations are allowed. However, air speed and air temperature are not uniformly distributed in the total volume of the incubator due to obstruction of the eggs and egg trays. The objectives of this research were (1) to quantify the spatiotemporal gradients in temperature and velocity and (2) to develop and validate a control algorithm to increase the uniformity in temperature during the entire incubation process. To improve the uniformity of air temperature, the airflow pattern and the air quality need to be controlled more optimally. These data show that the air temperature between the eggs at a certain position in a large incubator is the result of (1) the mean air temperature of the incubator; (2) the exchange of heat between the egg and its micro-environment, which is affected by the air speed at that certain position; (3) the time-variable heat production of the embryo; and (4) the heat influx or efflux as a result from the movement of hot or cold air in the incubator toward that position, which is affected by the airflow pattern. This implies that the airflow pattern needs to be controlled in a more optimal way. To maximize the uniformity of air temperature, an active and adaptive control of the three-dimensional (3-D) airflow pattern has been developed and tested. It was found to improve the spatiotemporal temperature distribution. The chance of having a temperature reading in the interval from 37.5 to 38.1 degrees C increased by 3% compared to normal operating conditions.

Air Movements↗
PubMed2003

Active control of the growth trajectory of broiler chickens based on online animal responses.

The objective of the research reported here was to control the growth trajectory of broiler chickens during the production process based on an adaptive compact dynamic process model. More specifically, the daily feed supply was calculated, based on a model-based control algorithm, with the aim of following a previously defined target growth trajectory as close as possible. For the modeling of the dynamic growth response of broiler chickens to the control input, feed supply, an online parameter estimation was used. The developed control algorithm was able to grow the birds according to different target trajectories ranging from restricted (final BW of 1,800 g and 1,945 g in experiments 1 and 3, respectively) to compensatory growth trajectories (final BW of 2,400 g and 2,100 g in experiments 2 and 4, respectively). The mean relative error (MRE) between the different predefined target growth trajectories and the realized growth trajectories ranged from 3.7% to 6.0%. With a few exceptions, the numerical values of feed conversion ratio and mortality after wk 1 were lower and the values of uniformity index were higher in the controlled groups compared with animals fed ad libitum. As a conclusion, it can be stated that integration of dynamic data-based modeling approaches with new hardware and sensing techniques to measure information from the animals should make it possible to control broiler growth trajectories.

Algorithms↗
PubMed2000

Modelling the static and dynamic responses of total heat production of broiler chickens to step changes in air temperature and light intensity.

1. The objective of this work was to explore the possibilities of modelling the static and dynamic responses of total heat production of broiler chickens to step changes in temperature and light intensity (light-dark alterations) using compact dynamic model structures. 2. Seventy-seven experiments were performed in an open-circuit respiration chamber to measure the dynamic response of heat production to step variations in temperature and light (on/off). The animal responses were modelled using transfer function model structures. 3. It was demonstrated that the complex process of the dynamic response of heat production of broiler chickens to step changes in air temperature and light-dark alterations can be modelled assuming 1st order dynamics. The coefficient of determination between measured and simulated heat production was on average 0.83 for responses to air temperature and 0.93 for responses to light-dark alterations.

Animals↗
PubMed1998

Energy and protein metabolism between 3 and 6 weeks of age of male broiler chickens selected for growth rate or for improved food efficiency.

1. A new open-circuit respiration unit consisting of 6 respiration chambers, gas analysis unit and data-acquisition system is briefly described. 2. Energy and protein metabolism in broiler lines selected for improved food efficiency (FC) or for growth rate (GL) were measured weekly from 3 to 6 weeks of age. 3. Gross and apparent metabolisable energy intake per kg W0.75 was on average higher for GL than for FC chickens without differences in metabolisability. Fed and fasted heat production per kg W0.75 did not differ between the lines. FC chickens retained less energy per kg W0.75 than GL chickens. 4. FC chickens deposited much less of the retained energy as fat than their GL counterparts and also showed greater protein conversion efficiency. The leaner composition of the body weight gain in FC chickens was confirmed by the estimated lower fat deposition per kg W0.75 and by the lower fat: protein ratio.

Aging↗
PubMed1997

Image analysis to measure activity index of animals.

The objective of the study was to present a method to quantify the behavioural response of animals to their micro-environment by using a camera system and a digitiser board. An algorithm was developed for analysing images and calculating activity, occupied zone and boundary of the animals. The developed method was tested on 3 different applications and animals. In the first application, the behavioural responses of broiler chickens to their thermal environment was measured. In the second application behavioural responses of pigs to their thermal environment were measured. In the third application, the response of water fleas to a chromium pollution was measured using the developed technique. Based on the experimental results, it can be concluded that the developed image analysis technique can be employed to quantify the behavioural responses of the tested animals to their micro-environment, in an easy and accurate way.

Adaptation, Physiological↗
PubMedDate not supplied

Assessing the sound of cough towards vocality.

The presented research positively evaluates the vocality of the cough sound by estimating the global cough fundamental frequency or pitch. The fundamental frequency was determined by autocorrelation analysis on both the original time-signal and the linear predicted time-signal. The experimental cough database was registered in the free acoustical field on respectively three pathological and nine healthy non-smoking human subjects and on two pathological and two healthy Belgian Landrace piglets. For both species differences between pitch values for cough-sounds originating from subjects suffering from a respiratory infection and healthy subjects are put forward. The retrieved pitch-difference between respectively healthy and infected subjects indicates the existence of acoustically different cough-classes in accordance with a different cause or physical condition of the respiratory system.

Acoustics↗