Assessing the adaptation of swine to fifty-seven hours of feed deprivation in terms of behavioral and physiological responses.

Dramatic changes in the livestock industry have brought about widespread concern regarding the welfare of animals in terms of the hunger that they may experience. Despite this concern, animal science has not been able to provide a methodology that can objectively determine whether the welfare of animals is compromised by hunger. The current work sought to provide data that characterized the physiological and behavioral responses of animals experiencing 57 h of food deprivation. For this purpose, 2 separate experiments were conducted, in which physiological or behavioral measures were collected from swine deprived of feed for 21 to 57 h or fed normally (physiology, n = 20/treatment; behavior, n = 8/treatment). Treatment x time interactions were found (P < 0.02) for insulin, beta-hydroxybutyrate, NEFA, drinking, standing, inactivity, lying sternal, lying lateral, and total lying. Animals appeared to adjust appropriately to the metabolic challenge imposed, as suggested by increases in alternative energy substrates (NEFA, beta-hydroxybutyrate). Additionally, feed-deprived animals appeared less active than control animals until after 45 h of feed deprivation, when the former appeared to be more active. Our results suggest that feed deprivation of finishing pigs for durations greater than 45 h produced behavioral changes that may be related to increased sensations of hunger and which possibly are dependent on the use of alternative energetic substrates. Our data link behavioral and physiological changes after the imposition of feed deprivation.