On the interpretation of feeding behaviour measures and the use of feeding rate as an indicator of social constraint

This paper highlights a number of issues associated with the use and interpretation of feeding behaviour measures using examples from the literature on rats, cows and pigs. The inter-relatedness of six feeding behaviour variables is illustrated. Different meal patterns adopted to achieve similar intakes are briefly discussed in the context of flexibility of feeding behaviour. The relative constancy of feeding rate of an individual in a given environment is described, and the notion of a preferred rate of eating is introduced. It is suggested that an animal kept individually will eat a given amount of food at a preferred rate of eating. Changes in feeding rate by individuals are examined and different causes discussed. These include increased feeding motivation (hunger), and influences from the social environment. It is proposed that changes in the feeding rate of individual group housed animals may reflect concomitant changes in the social environment, and could thus be used as an indicator of social constraint. In addition, it is proposed that the depression in daily food intake seen in group housed animals compared to single kept individuals may reflect a shift in behavioural priorities. (C) 1999 Elsevier Science B.V. All rights reserved.