The continuum between conditioned preferences and aversions in ruminants to flavoured foods associated with the increasing administration of casein doses

Abstract

In recent years there has been an increasing interest in the question of how ruminants develop conditioned flavour preferences or aversions (CFP's, CFA's) towards food flavours associated with the administration of various substances. Several studies have shown that ruminants are able to develop CFA's when pairing a novel food flavour with the administration of secondary compounds which lead to adverse post-ingestive consequences (e.g. activation of the emetic system, hypocalcaemia, Kyriazakis et al., 1997). In addition, CFP's, can be developed through associations between the food properties and the administration of nutrients which lead to positive post-ingestive consequences (e.g. increased nitrogen supply, Villalba and Provenza, 1997). The purpose of this study was to investigate whether a continuum exists between CFP's and CFA's which are developed towards a food flavour associated with the administration of the same nutritive stimulus, given at increasing doses. In addition, the rate of establishment and degree of extinction of such food CFP's and CFA's was also investigated.