Effects of transport time of steers before slaughter on behaviour, weight loss and some carcass characteristics

The effects of 4 road transport times (3, 6, 12 and 14 hr) of steers before slaughter on behaviour patterns, live and carcass weight losses, and some carcass characteristics such as dressing yield, frequency and grade of brui sing, pH and muscle colour were evaluated. Two experiments were carried out , one in autumn-winter (OI) and another in spring-summer (PV), with a total of 139 steers of the Friesian breed, all of similar age, live weight and f at cover. Two lorries of similar structure and capacity were used. giving a space allowance of 1 m(2) for every 500 kg liveweight; according to the we ight of the steers this was equivalent to 17 or 18 animals per load, and ea ch load corresponded to one treatment. The steers were weighed on the farm just before loading, at their arrival at the slaughterhouse and prior to sl aughter (after 12 +/- 1 hr lairage). The carcasses were weighed immediately after slaughter; pH and colour (Hunterlab) were measured on the Longissimu s thoracis muscle, 24 h after slaughter. Descriptive statistics, an analysi s of variance and Tukey test were used to determine differences between tre atments within each experiment. Weight losses during transport were 6.5(a); 5.0(b); 6.0(a) and 10.5(c)% in OI; and 4.6(a); 7.3(b): 8.9(c) and 11.9(d) % in PV, for 3, 6, 12 and 24 hou rs, respectively (P less than or equal to 0.05). No losses in terms of carc ass yield were registered due to longer transport times. A higher overall n umber of bruises was found in the steers transported for 24 hours. Two anim als went down in journeys of 12 hours and 7 animals went down in journeys o f 24 hours, whilst no steers fell when transported for 3 or 6 hours. The me an pH found in the carcasses of steers transported for 3, 6, 12 and 24 hr r espectively was 5.5(a), 5.6(a), 5.6(a) and 5.8(b) in OI; and 5.9(a), 5.6(b) , 5.6(b) and 5.7(b) in PV (P less than or equal to 0.05). Mean colour light ness (L) of Longissimus thoracis surface was 28.5(a), 27.5(ab), 26.2(ab) an d 24.5(c) in OI and 23.7(a), 25.9(b), 26.1(b) and 25.8(b) in PV with 3, 6, 12 and 24 hr transport, respectively (P I 0.05). It was concluded that for steers, a transport time of 24 hours by road produces higher live weight lo sses, more bruises and more animals fall during the journey than shorter tr ansport times therefore. it should be avoided. The results for pH and colou r indicate that long journeys as well as short journeys can produce increas es in final pH and darker meat, depending on the conditions of each journey .