肉用牛の輸送ストレスに対する削蹄の効果

Abstract

The purpose of this study is to determine effects of hoof trimming on transport-induced stress in beef cattle. Forty-one Japanese black steers were randomly divided into 2 groups: trimmed group (n=27) and untrimmed group (n=14). In the trimmed group, hoof trimming was repeated every 6 months, with the final trimming performed 3 months before shipment. The untrimmed group was not trimmed at all until shipment time. Before and after truck transportation to the shipping destination (57.8 km, 4 hours), the cattle were weighed, and their blood was sampled for hematological and biochemical analysis. The indices of transport-induced stress were creatine phosphokinase (CK) and cortisol. In both groups, CK and cortisolincreased after transportation. Increase in the parameters was lower in the trimmed group than in the untrimmed group. Lower CK activity in the trimmed group suggests that the physical demand for posture support during transport in the vehicle was more restricted in thetrimmed group. Plasma cortisol increased less in the trimmed group than in the untrimmed group. This could mean that periodical trimming effectively inhibits transport-induced stress in beef cattle.