Effect of iron bioavailability on performance, feed digestibility, blood parameters, and carcass characteristics at slaughter of grain-fed veal calves

Abstract

Scott, S. L. and Ghodratnama, A. 2004. Effect of iron bioavailability on performance, feed digestibility, blood parameters, and carcass characteristics at slaughter of grain-fed veal calves. Can. J. Anim. Sci. 84: 639-649. The effects of the iron chelator, EDTA, on performance, feed digestibility, blood parameters, and carcass quality were investigated in 48 veal calves (52 ± 4 kg BW) allocated to five treatment groups: a control, 5 mg EDTA mg -1 Fe in the feed for the last 8 or 18 wk before slaughter, or 15 mg EDTA mg -1 Fe in the feed for the last 8 or 18 wk before slaughter. Calves were fed a diet of whole corn and protein supplement (grain: supplement ratio of 2:1, 3.5:1 and 5:1 for starter, grower, and finisher production phases, respectively, resulting in crude protein levels of 21, 18 and 15%, respectively). The effects of both dose and duration of EDTA administration were analysed using a randomised complete block design in a factorial model. Daily DMI and ADG decreased linearly with an increasing dose of EDTA (P < 0.001). ADG declined linearly with increasing dose and duration of EDTA administration (P < 0.05). Blood iron, haemoglobin and haematocrit levels decreased linearly with increasing EDTA dose (P < 0.001) and duration of administration (P < 0.05). Carcass weight (kg) and yield (%) decreased linearly with both increasing EDTA dose (P < 0.001) and duration of EDTA administration (P < 0.05). Carcass classification improved linearly with increasing EDTA dose (P < 0.01). When EDTA is used as a dietary supplement for veal calves, there may be beneficial effects on carcass classification, but the dose and duration of administration need to be chosen judiciously to avoid deleterious effects on the well-being of the calves.