Abstract
To determine the stress resistance of steers to long distance transport, two field studies were conducted. First, the physiological responses of 16 steers reared in two farms (Farms I and II) that adopted different suckling and growing systems were compared. Although big difference between the farms was found in the total time of management procedures at the growing stage (Farm I : 233.1 vs. Farm II : 48.8 min/head), physiological responses of steers after transport were not significantly different between farms. Serum ALT concentration and heart rate was higher just after transport compared with I wk after transport in the steers reared in Farm I (both P<0.01), but not in the steers reared in Farm II. The time length of hand procedures with touch at the growing stage was longer in Farm 11 (2.9 min/head) than in Farm I (0.7 min/head). Secondly, the physiological responses of 16 steers reared in two milk feeding systems were compared. The mean liveweight of steers reared in a group in automatic milk feeding (321.4±22.9kg) was heavier than that of steers individually reared in hand milk feeding (298.2±19.4kg) (P<0.01). The time length of hand procedures with touch at the growing stage was longer in automatic milk feeding (23.7 min/head) than in hand milk feeding (0.7 min/head). Serum pH was lower just after transport compared with I wk after transport in the steers reared in hand milk feeding (P<0.05), but not in the steers reared in automatic milk feeding. Serum ALT concentration (P<0.01) and heart rate (P<0.05) were higher just after transport compared with I wk after transport in the steers reared in hand milk feeding, but not in the steers in automatic milk feeding. These results indicate relatively low stress resistance to transport in calves reared in the management system that the stockpersons have little contact with their cattle at growing stage. Furthermore, group housing from suckling stage would make easy for calves to adapt to a novel environment and unfamiliar cattle after transported.
