LAUSR

The effects of restricting iron intake for the final 60 days of a 180-day growth trial on growth performance, nutrient digestibility, slaughter performance and meat quality of dairy bull calves used in veal production were evaluated in this study. Twenty-four newborn Holstein bull calves with an average weight of 41.0 ± 1.62 kg were randomly assigned to two groups of n = 12 calves/group. Calves in the Control group were fed a basal diet that included a milk replacer and pellet feed for 180 days. The iron level in the basal diet was 50 mg/kg. Calves in the Treatment group received the basal diet supplemented with 70 mg/kg iron for the first 120 days, then received the basal diet for the remaining 60 days. Five calves from each group were slaughtered at the end of the trial, and samples of the M. longissimus dorsi and rumen fluid were collected. No differences were found in dry matter intake, growth performance or digestibility and metabolism of nutrients between the two groups (P > 0.05). The dietary iron regimen did not affect the concentrations of blood urea nitrogen, total protein, albumin, or glucose (P > 0.05); however, the haemoglobin content increased with the supplementation of iron in the diet (P < 0.05). Compared with the Control group, increasing dietary iron increased the meat percentage (P < 0.05) rather than the meat nutritional composition or quality of veal.