Relationship between reluctance to eat novel foods and open-field behavior in sheep

Fear, a key aspect of temperament with important implications for both animal welfare and production, may be manifest in responses to novelty. Herbivores typically prefer the familiar to the novel, and they generally regard anything novel with caution (i.e., they are reluctant to eat novel foods). We hypothesized animals differ in their fearfulness towards food and non-food items due to individuality which is influenced by genetics and contrasting environmental experiences. We further hypothesized fear of unknown foods and environments are correlated. Our objective was to determine if sheep differ in their fear responses and whether or not there is a link between general fearfulness and response to separation - as measured by the open field test (OFT) and stress induced hyperthermia (SIH) - and the readiness to eat new foods. We assessed reluctance to eat novel foods, open field behavior, and SIH in two groups of sheep (Group 1: Rambouillet-Columbia-Finn-Targhee crossbreds; Group 2: composite Suffolk) raised under contrasting environmental conditions. Lambs in Group 1 showed lower number of bleats and higher SIH than lambs in Group 2. When offered novel foods, lambs in Group 1 were more reluctant to eat them than lambs in Group 2. There was a negative relationship between number of bleats in OFT and reluctance to eat novel foods. Thus, reluctance to eat novel foods and response to separation in the OFT behavior differed among animals and a correlation was found between these behaviors. Our results suggest that reluctance to ingest new foods is influenced by sociality. Individuals less responsive to social isolation (lower number of bleats) may be less cautious at accepting novel foods than individuals more responsive to social isolation. Such variability implies some individuals may be more adept at consuming diverse diets in diverse locations whereas others may be more adept at consuming single foods at fixed locations.