Abstract: In this study we examined how social learning of feeding preferences by zebra finches was affected by the identity of different demonstrators. We presented adult zebra finches with two demonstrators, one male and one female, that exhibited different food choices, and we recorded their subsequent preference when given a choice between the two food types. Previously it was found that young zebra finches' patterns of social learning are affected by the sex of the individual demonstrating a feeding behaviour. This result could be explained by the lack of exposure these animals had to the opposite sex, or by their mating status. Therefore, we investigated the social learning preferences of adult mated zebra finches. We found the same pattern of directed social learning of a different type of feeding behaviour (food colour): female zebra finches preferred the colour of food eaten by male demonstrators, whereas male zebra finches showed little evidence of any preference for the colour of food eaten by female demonstrators. Furthermore, we found that female observers' preferences were biased by demonstrators' relative feeding activity: the female demonstrator was only ever preferred if it ate less than its male counterpart.

Abstract: High carbohydrate diets can affect the health and behaviour of foals, but the mechanisms are not always fully understood. The objective of this study was to compare the effects of feeding a starch and sugar (SS), or a fat (oil) and fibre (FF) rich diet to two groups of eight foals. Diets were fed from 4 to 42 weeks of age, alongside ad libitum forage. Faecal pH levels did not differ significantly between groups and endoscopic examination showed that the gastric mucosa was healthy in both groups at 25 and 42 weeks of age. At 40 weeks of age, SS foals had significantly higher total blood glucose and lower total blood gastrin than FF foals during the 6h period following ingestion of their respective diets, but insulin levels did not differ significantly. The ratio between serum tryptophan and other large neutral amino acids showed a trend towards an interaction between diet and sampling time. The results provide preliminary information about the effects of diet on the physiology of young horses.

Abstract: Abstract Concentrated feed diets have been shown to drastically increase the rate of the cribbing, an oral stereotypy in horses, but the specific component causing the rise has not been identified. Furthermore, the mechanism through which feed affects cribbing has not been explored. In the first experiment of this study, we quantified the latency to crib and number of cribs in 15 min after the horses tasted various grain, sugar, and artificial sweetener solutions. Undiluted grain stimulated the most cribs (P < 0.01) compared with all other solutions, and shortest latency to crib, although this was significantly higher only when compared with diluted grain (P = 0.03). In Experiment 2, latency to crib and number of cribs in 15 min after the grain and sugar solutions were administered via nasograstric tube were also evaluated. There were no statistical differences among cribbing responses to grain, fructose, and water administered directly to the stomach although grain stimulated cribbing behavior more quickly than 10% fructose (P = 0.03) and 100% tap water (P = 0.04). These results confirm that highly palatable diets, possibly mediated through the opioid and dopaminergic systems, are one of the most potent inducers of cribbing behavior. The highly palatable taste remains the probable “cribogenic” factor of concentrated diet, although gastric and post-gastric effects cannot be excluded.