unopened whole straw bale processing with urea is better than opened straw bale processing in feedlot systems

in order to investigate the effect of processing type (whole straw bale processing or opened straw bale processing with urea) on diet digestibility, economical and productive parameters in feedlot cattle, 18 holstein bull with average body weight 224.72 ± 20.45 kg were used in a completely randomized design with 3 treatments and 6 replicate. treatments 1, 2 and 3 contained 40% typical straw, 40% whole straw bale processed with 5% urea (wsbp) and 40% opened straw bale processed with 5% urea (osbp), respectively. the average in vitro digestibility of dm (32.7, 46.9 and 46.5%, respectively for treatments 1 to 3) and om (30.5, 47.0 and 45.8%, respectively for treatments 1 to 3) was not significant between wsbp and osbp, but was significant between treated and typical straw. the average daily gain (698, 881 and 882 g/d, respectively for treatments 1 to 3) and daily dmi (8.8, 10.2 10.0 kg/d, respectively for treatments 1 to 3) were significantly higher for wsbp and osbp compared to typical straw. the cost price of consumed diet for 1 kilogram weight gain was 910 rials lower for wsbp than typical straw. also, the time require to achieve 200 kg weight gain reduced to approximately 2 month. the results of present study showed that processing of wsb can reduce needed time and labour cost, and in comparison with typical straw time required for achieving weight gain reduced.