Growth Performance, Behaviour, Forestomach Development and Meat Quality of Veal Calves Provided With Barley Grain or Ground Wheat Straw For Welfare Purpose

Abstract

Two different feeding plans for veal calves were compared in the study: a traditional liquid diet supplemented with 250 g/calf/d of barley grain or with 250 g/calf/d of ground wheat straw. The two solid feeds had different chemical composition but a similar particle size obtained by grinding the straw in a mill with an 8-mm mesh screen. Twenty-four Polish Friesian male calves were used in the study and they were housed in individual wooden stalls (0.83 x 1.80 m). The health status of all the calves was satisfactory for the entire fattening period and no specific medical treatment was required during the trial. Calves fed wheat straw showed a greater intake of solid feed (196 vs. 139 g/d; P<0.01) and a higher average daily gain (1288 vs. 1203 g/d; P<0.05) than those receiving barley grain. The consumption of milk replacer was not affected by the type of solid feed and no milk refusal episodes were detected. The haemoglobin concentration was similar in calves receiving the two feeding treatments despite the higher iron intake provided by the wheat straw throughout the fattening period (2.12 vs. 1.15 g; P<0.001). It is likely that the iron in wheat straw was less available for the calves’ metabolism. Feeding behaviour was affected by the provision of solid feeds. Eating and chewing were prolonged in calves receiving ground wheat straw and the same solid feed reduced the frequency of oral stereotypies at the end of the fattening period. At the slaughterhouse, no differences were observed between the feeding treatments as regards carcass weight and dressing percentage. The calves fed ground wheat straw had a heavier weight of the empty omasum (518 vs. 341 g; P<0.01) whereas the empty weight of the reticulorumen and abomasum were similar to those of calves fed barley grain. The incidence of abomasal erosions, ulcers and scars was similar in both treatments; however the index of abomasal damage, which considers the number and the seriousness of different type of lesions, was higher in calves receiving barley grain. Therefore, the grinding of straw particles, as opposed to barley grain, can reduce the abrasiveness of roughage at the abomasum level. Visual evaluation of the carcass colour and instrumental measurement of meat colour did not show significant differences between diets. The study confirmed that in the veal calf, carcass and meat colour are not strictly correlated with the iron intake from solid feeds.