Abstract
In order to analyze aspects of the cohesive tendency in cattle, the behaviours of grazing cattle were investigated for 20 days from June to August. The investigations were done in a herd composed of 12 Japanese Shorthorn heifers, 6 Japanese Black steers, 6 Holstein steers and one Japanese Shorthorn bull grazed on a native grassland of about 90 ha at Kawatabi Farm of Tohoku University. As some subgroups were formed in a herd while grazing, the composition of each subgroup and the location and body axis of all cattle were recorded at 10 minutes intervals in order to analyze the distribution and character of each cattle in a herd. Results are summarized as follows: 1) Holstein cattle showed the most marked breed integration. Japanese Black cattle had the strong tendency to from the subgroups within breeds rather than between breeds. Japanese Shorthorn cattle exhibited weak own-breed integration and preferred the Japanese Black breed. 2) In the subgroups while grazing, the differences in the locations and body axis of cattle among breeds were significant. Japanese Shorthorn cattle exhibited the weak tendency to follow neighbours rather than the other breeds did. Holstein cattle hardly differ from neighbours in behaviour, while Japanese Black cattle were not always at the heads of moving columns. 3) Some individuals with weaker cohesive tendency were frequently at the heads of moving columns or moved away from their neighbours while grazing. 4) A hull mostly move away from their neighbours and didn't show the grazing behaviour while the other cattle exhibited grazing behaviours. 5) The grazing formations which had only one direction of the grazing movement and contained some individuals that were at the front of a moving column, so to speak the pear-shaped grazing formations, were 47% of total grazing formations, so it was considered that this grazing formations were typical. 6) The grazing formations which had several directions of the grazing movement were 33% of total grazing formations. Therefore, it was clear that a herd always had a sign of separation of subgroup while grazing.
