Development of a multidiscipline approach to assess feed deprivation in swine using physiological, behavioral, neurological, and pharmacological methods
Dramatic changes in the livestock industry have brought about widespread concern regarding the welfare of the animals and associated hunger that they may experience in a variety of situations. Despite this concern, animal science has not been able to provide a methodology that can objectively determine whether the welfare of the animals is compromised due to hunger. Several issues have made this objective difficult, most critically the lack of a consistent measure of stress or an objective means to quantify welfare and subjective experiences. The present work sought to review evidence of hunger in livestock operations and propose several specific and unique methodologies to identify when an animal is actually experiencing hunger and the severity of that hunger in terms of practical and objective data. The methodologies proposed build upon responses that have been observed to be dependent on the level of hunger an animal is experiencing. Specifically, animals were subjected to feed deprivation ranging from 21 to 57 h and then specific responses were measured to determine how hunger imposed by the deprivation period affected the responses. Specific measured responses included neurohormones, physiological hormones and metabolites, behavior, and feeding activity in response to an appetite suppressant. Resulting data were analyzed to determine the effects of feed deprivation and length of feed deprivation on measured responses. The current work provides a thorough and multidiscipline effort to determine how feed deprivation and associated hunger affects an animal as it adapts to the metabolic challenge. Additionally, our analysis can be utilized in a manner where animals in future research of dietary manipulations can be classified into a particular class or level of hunger. Once animals are classified within a particular level of hunger, the multidiscipline data generated in regards to that class of hunger can be used as a foundation to assess the impact of that diet on an animal's welfare. Ideally, future research in dietary manipulations can compare their responses to the data generated from the current study and draw conclusions based on which range of deprivation their animals most closely resemble.
Lay, Purdue University.
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