Meat quality and transport stress of cattle.Dtsch Tierarztl Wochenschr. 2003 Mar; 110(3):125-8.DT
This study evaluated the effect of transport time up to 14 hours and the effects of vehicle design on animal welfare, stress and meat quality. 18 transports (six short, medium and long) with a total of 486 animals (118 sample animals, heifers and bulls) were carried out on commercial vehicles in summer 2000 and winter 2001. Animal welfare and stress were evaluated by blood serum parameters, heart rate monitoring, behaviour recording and occurrence of carcass bruising. Meat quality was evaluated by post mortem muscle glycogen content, pH value, temperature, drip loss, colour and tenderness measurements. Heifers had lower heart rates than young bulls during loading (95 vs 114 beats per minute, bpm), whereas during transport, both had an average heart rate of 100 bpm, furthermore during unloading, heifers had higher heart rates than bulls (109 vs 100 bpm). Blood sampling during unloading could have marginally increased heart rates during the unloading procedure. Studied cattle had lower heart rates during medium and long distance transports compared with short transports. Monitoring of animal behaviour during transport showed that the former settled down faster than the latter. Single- and two-animal pens in medium and long distance vehicles prevented nervous and stressful movements of cattle, which were more prominent in large pens of short distance lorry. Present results suggest that larger pens of three or four animals could increase cattle stress during transport. Moreover during unloading, cattle loaded in single- or two-animals pens had significantly lower blood cortisol content than those loaded in larger groups of three or four animals (P < 0.01). The amount of severe carcass bruising was highest in animals transported over short times and loaded into groups of four cattle. Severe damages occurred most often on perianal and hipbone area of the carcass surface. Present results showed that muscle glycogen level was highest after long transport. These animals were fed more regularly from the last feeding up to stunning than medium or short distance animals. Animals in single-pens had the highest muscle glycogen level. Transport distance or number of animals in one pen had a minor effect on muscle pH values or temperatures during 24 hours post mortem (pm). Drip loss of the M. longissimus dorsi (LD) was highest after long transport, but animal number in one pen had no effect on drip loss. Colour of the LD muscle was independent on transport conditions. Light colour of three animal groups resulted from high amounts of heifers, which had lighter colour than bulls. All meat samples were quite tender. However, heifers had significantly tender meat than young bulls (P < 0.001). Higher amounts of heifers had the most tender meat after short transports. Mean DFD (dark, firm, dry) meat occurrence was 2.1% in this project, DFD frequency was lowest after short, then after long and highest after medium distance transports. Because of not evenly distributed numbers of bulls (low) and heifers (high) it was difficult to compare short and long distance transport effects.