Review: Quantifying animal feeding behaviour with a focus on pigs

Abstract

The study of animal feeding behaviour is of interest to understand feeding, to investigate the effect of treatments and conditions or to predict illness. This paper reviews the different steps to undertake when studying animal feeding behaviour, with illustrations for group-housed pigs. First, one must be aware of the mechanisms that control feeding and the various influences that can change feeding behaviour. Satiety is shown to largely influence free feeding (ad libitum and without an operant condition) in animals, but 'free' feeding seems a very fragile process, given the many factors that can influence feeding behaviour. Second, a measurement method must be chosen that is compatible with the goal of the research. Several measurement methods exist, which lead to different experimental set-ups and measurement data. Sensors are available for lab conditions, for research on group-housed pigs and also for on-farm use. Most of these methods result in a record of feeding visits. However, these feeding visits are often found to be clustered into meals. Thus, the third step is to choose which unit of feeding behaviour to use for analysis. Depending on the situation, either meals, feeding visits, other raw data, or a combination thereof can be suitable. Meals are more appropriate for analysing short-term feeding behaviour, but this may not be true for disease detection. Further research is therefore needed. To cluster visits into meals, an appropriate analysis method has to be selected. The last part of this paper provides a review and discussion of the existing methods for meal determination. A variety of methods exist, with the most recent methods based on the influence of satiety on feeding. More thorough validation of the recent methods, including validation from a behavioural point of view and uniformity in the applied methods is therefore necessary.

Conditioning Methods for Animals in Agriculture: A Review

“…Pigs tested with food rewards in two operant conditioning tasks helped support the idea that food can be used as a motivator in learning behaviors (55) , which suggests that handlers and managers can use food as a reward in positive reinforcement training and to assist with habituation to humans and handling. This further supports the idea that a better understanding of how learning and habituation affects behavior can help managers develop better practices for developing safer, less stressful management techniques and provide for better observation practices dedicated to detecting early stages of stress or disease (72) . Further developments in science will also help improve researchers' abilities to determine links between biological measures and pig behavior which will help improve the understanding of pigs and increase welfare and production through the development of better management practices (73) .…”

How to quantify animal activity from radio‐frequency identification (RFID) recordings

“…Although the reader sample interval can usually be programed in accordance with the anticipated speed, it may be that animals move faster through the registration zone than the quickest possible scanning interval of the logger. Moreover (5), when two or more tags are simultaneously present in the registration zone, some logger types can register only one of them (Maselyne, Saeys, & Van Nuffel, ). Damage to the casing of the tag (6) is another rare problem that may result in absent signaling.…”

Multi-object extraction from topview group-housed pig images based on adaptive partitioning and multilevel thresholding segmentation

“…However, the error segmentation mentioned above only exists in a small number of frames and lasts a very short time because pigs that are drinking or feeding often do not like to be disturbed. 3) Individual pig recognition: Individual pig recognition usually uses ear-tags (Maselyne, Saeys, & Nuffel, 2015), and automatic recognition of individual pigs by image analysis in a pen has not yet been reported in the literature. identified pigs individually by their unique marking patterns.…”