Behavioural response towards twelve feedstuffs in lambs

The feeding behaviour of 28 Merinos lambs reared in intensive conditions was evaluated considering the palatability and preference of 12 feedstuffs. To determine palatability, every day, one of the 12 foods was administered ad libitum for 30 min. After the first 12 days the experiment was repeated. Feeding behaviour was evaluated considering the amount of food eaten, the time the animals spent eating, and the food intake rate of eating. To determine the food preference, another test was performed in two consecutive periods of 7 days each. The animals were divided by weight into two homogeneous groups. Every day, all 12 feedstuffs were offered ad libitum for 24 h. After the first 7 days, the arrangement of the food was changed. The food preference was evaluated considering the amount of food eaten. The weight and growth rates of the animals during the tests were also considered. Palatability was influenced by food type, food texture and period. In particular, all foods were less palatable in the first then in the second palatability test. Also, the palatability order changed between the first and the second test. The preference changed during time too. Neither the more palatable nor the less palatable foods were preferred during the tests. Lambs preferred the foods with an intermediate level of palatability. The results underline the dynamics of palatability and preference, and contribute to clarifying the relationships between the two. Palatability is influenced by food composition and shape, and by the animals' physiological state and experience. High and low palatability indexes reduce preference through negative post-ingestive feedbacks