Determination of the weight of individual pigs housed in groups is of interest to engineers and scientists working on various aspects of pig production as it relates to nutrition and behaviour . This paper describes experiments and data analysis aimed at developing a technique to determine the weight of individual pigs without interrupting their normal daily routine . An electronic weighing platform that weighs the front legs and real time filtering of the data using a Kalman Filter was found to provide satisfactory estimates (standard deviation Ο 1 ΠΈ 55 kg) of the weight of 16-week-old pigs while feeding . The weight range of the pigs was 30 -50 kg . Γ· 1996 Silsoe Research Institute .
1 . Introduction
Although there are many examples of electronic data acquisition of both physiological and performance variables of live animals that have been individually housed , the measurement of similar variables on groups of animals has proved more challenging , especially when it is to be integrated into normal commercial animal husbandry .
The work in this paper was undertaken as part of a project to investigate the feed intake and feed wastage of pigs in the weight range of 20 to 80 kg . As part of the project , means of ascertaining the weight of individual animals within the group was sought that did not incur the cost and disturbance of excessive human intervention . Two issues were of particular interest in the study , namely , how feed intake and wastage were af fected by the design of the feeder and by the behavioural aspects of the feeding pig . In order to study these two aspects it was deemed essential that the data acquisition procedure did not alter the normal feeding behaviour or the appearance of the feeder for the group of pigs .