Testing responses to novelty in cattle: behavioural and physiological responses to novel food

In order to develop a behavioural test as well as gain information about behavioural response to novel food, we performed four experiments with cattle kept in tie-stalls and observed the behaviour (approach/avoidance, self-grooming and consummatory behaviour) for 10 (experiment 3 and 4) or 30 (experiment 1 and 2) min after provision of novel food. In experiment 1, the effects of the novelty of the feeding method were tested using nine heifers provided with 2 kg of their usual food from the usual fodder truck or from a basket made of plastic. The novel feeding method induced increased sniffing, decreased duration of eating and increased self-grooming. The effects of the degree of novelty of a food were examined in experiment 2 using heifers (no. = 8 to 12) and three concentrations of fish oil (1.5, 6 or 24 g/kg) and eucalyptus oil (5, 20 or 80 drops per kg) added to the usual food. Increasing the concentration of eucalyptus oil in the food led to changes in behaviour, while the addition of fish oil led to a less clear response. However, both suggested that the behaviour reflected the degree of novelty in the food. Behavioural responses to two novel foods (4 kg carrots v. 80 drops per kg of eucalyptus oil added to the usual food) as well as individual characteristics and repeatability within 72 h were examined in experiment 3. The behavioural responses to the novel foods differed, showing a higher level of approach and attempts to eat the carrots, and responses to the two different novel foods were not correlated. At the second provision, the acceptability of the carrots was greater, however responses to carrots showed an acceptable repeatability. Finally, the cardiac (heart rate) and behavioural responses to usual food and novel food (4 kg carrots) were compared in experiment 4. Provision of novel food led to behavioural signs of motivational conflict and neophobia while the heart rate tended to be lower than when the cows were provided with usual food. These results provide evidence that behavioural responses to novel food in cattle include signs of motivational conflict between eating motivation and neophobia, reflecting the degree of novelty in the test situation including the feeding method. However, palatability of the food might also affect the responses, and the data on heart rate suggest that novel food is not a fear-inducing stimulus.