Behavioral reactivity of cattle toward novel food: effects of testing time and food type of neighbors.

Abstract

In order to improve methods to investigate individual variation in responses of cattle toward novel food, the influence of food type offered to neighbors and time of testing were investigated in tethered heifers. Twenty-four Danish Friesian heifers were used in two 2 x 3 factorial experiments, using 8 kg of a mixed ration (grass silage and concentrates) and 4.5 kg of carrots as a novel food. The factors were 1) time of testing: heifers tested at usual feeding time (1000) vs after 30 min with access to their usual food; and 2) food type of neighbors: either no food, novel food, or usual food. During the 30-min period with novel food in front of them, the behavior of the experimental heifers was video recorded. Testing at usual feeding time led to a tendency to increase the latency to eat the mixed ration (P = 0.08), a tendency to reduce intake of the mixed ration (P = 0.08), increased frequency and duration of sniffing carrots (P = 0.1 and P = 0.02, respectively), increased duration of sniffing the mixed ration (P = 0.05), and decreased frequency and duration of disturbance from neighbors (carrots: P = 0.0002 and P = 0.003). The food type of the neighbors did not have major influence on the behavioral reactivity. For both the mixed ration and carrots, the frequency of eating was increased when the neighbors got novel food rather than their usual food (P = 0.01 and P = 0.02). However, the frequency and duration of disturbance from neighbors was increased when no food was offered to the neighbors (carrots: P = 0.001; mixed ration: P = 0.01 and P = 0.09, respectively). It is concluded that time of testing is an important factor for the behavioral response toward novel food, leading to increased responses when tested at the usual feeding time compared with testing after 30 min of access to usual food. The minor effects of food type of neighbors indicate that it is possible to perform individual testing in a home environment, where the animals have limited possibility for contact with neighbors.