Effects of various rehydration procedures after a long journey on liveweight, carcasses and muscle properties of cattle

Abstract

After a long journey of 1420 km, bullocks were watered without feed for 0, 3.5, 7, 28 or 32 h or watered with feed for 32 h prior to a 16 h preslaughter fast (no water and feed). The 108 bullocks in the first three treatments (36 per treatment) were slaughtered after resting for 1 day and the remaining 108 after resting for 2 days. Bullocks lost 10.4% of initial liveweight (656 kg) in transit. Mean liveweight of 588 kg on arrival increased when bullocks had access to water, so that after 3.5 h on water the net liveweight loss was reduced (P < 0.05) to 6.0 % of initial liveweight and after longer periods the loss varied from 6.8 to 7.3%. The net loss of the group also offered lucerne hay was 6.7%. More importantly, re-hydration increased (P < 0.01) gross hot carcass weight from 369 kg to 383 kg when bullocks were watered for 3.5 and 7 h, 381 kg after 28 h on water alone and 379 kg after 32 h on water and feed. However, this increment was not maintained, since the carcasses of bullocks on water alone for 32 h averaged 376 kg and were lighter (P < 0.05) than those of other bullocks on water. The water content of fat-free muscle reflected the same pattern as carcass weight (P < 0.01), although muscle water content peaked at 78.16% when bullocks were watered for 28 h compared with 76.01 % for those bullocks not offered water. Resting bullocks for 2 days rather than 1 day reduced (P < 0.01) the pH values of the M. longissimus dorsi 24 h post mortem from 5.64 to 5.57.