The influence of prior experience on food preference by sheep exposed to unfamiliar feeds and flavors

We explored the influence of dietary experiences on ensuing ingestive responses to novel feeds and flavors by lambs. Twenty lambs housed in individual pens were assigned to two groups (10 lambs/group). In four different periods, all animals were offered four different nutritive novel feeds (oats, wheat bran, corn, beep pulp), followed by intra-ruminal infusions of lithium chloride-LiCl (150 mg/kg BW), a toxicant that causes food aversions (Group NE; negative experiences with novel foods), or just or water (Group PE; Control). After exposure, all lambs were tested for their acceptance of single novel feeds (sorghum grain, rice bran, Calf manna (R) pellets and soybean meal) presented separately and simultaneously in 5-way preference tests with alfalfa (a familiar feed) at familiar and unfamiliar locations. Lambs were also tested for their acceptance and preference for novel flavors (onion, oregano, cinnamon, garlic) added to alfalfa at the unfamiliar location. During exposure, the PE group ate more of the novel feeds than the NE group (P < 0.05). During testing at both familiar and unfamiliar locations, PE lambs ate more (P < 0.05) of the novel feeds than NE lambs, displaying greater preferences for novel feeds and a greater Shannon's diversity index (P < 0.05). No differences between groups regarding ingestive behavior were observed when lambs were offered novel flavors at the unfamiliar location (P > 0.05), likely due to generalization of familiar cues in flavored alfalfa. Thus, prior negative experiences with novel foods increased neophobia and constrained dietary diversity during exposure to novel feeds, an outcome that could impact the composition and structure of plant communities, as well as the nutrition and welfare of grazing animals. Finally, nutritious and safe cues from familiar feeds may be important at attenuating the influence of such negative experiences in novel feeding environments.