The causation of foraging behaviour in the growing pig : the role of internal and external factors

• Main Author: Day, Jon Edward Lewis
• Published: University of Edinburgh 1995
• Subjects: 591.5
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.649235

This thesis examines in detail some of the internal and external factors which are implicated in the causation of foraging behaviour in growing pigs. Special reference is given to the interface between exploratory and feeding motivations, and the role of gastro-intestinal distension in determining the tendency to perform foraging behaviour. Four experiments were performed which found: 1. Extrinsic exploration equates to the appetitive component of the dominant motivation (e.g. extrinsic exploration for food and foraging), and therefore can be directly affected by the level of feeding motivation, whereas intrinsic exploration is not directly affected by the level of feeding motivation. 2. Chewing behaviour, such as tail-biting, is initiated through extrinsic exploratory behaviour, but then sustained by feeding motivation. In addition, feeding motivated chewing is moderately reinforced by taste, but is strongly reinforced and perpetuated by taste paired with a relevant source of feedback. 3. Growing pigs are able to respond for the repeated presentation of a feeding related conditioned stimulus in a manner which is indicative of their level of feeding motivation. This methodology allows feeding motivation to be measured in the absence of food ingestion. 4. The level of feeding motivation resulting from the ingestion of a bulky food is inversely proportional to the degree of gastro-intestinal distension. However, this effect is only temporary because feeding motivation responds primarily to the nutrient content of a meal.