The effects of different processing methods on chemical composition and ruminal degradability of canola straw and its effect on fattening performance of male Holstein calves

This experiment was carried out in order to determine of nutritive value of canola straw and its effect on fattening performance of male Holstein cluves. Canola straw (okapy variety) was provided from the seed and plant improvement Institute, Karaj, Iran. Canola straw was processed by urea, molasses, ammonia, peroxide and was stored in plastic bags for 28 days. This experiment was conducted in a completely randomized design with 7 treatments and 3 replicates in each treatment. Treatments included: 1 - not processed canola straw (control), 2- processed with urea (5.3 % of DM), 3- processed with urea + molasses (5.3 % of DM urea + 2 % of DM molasses of DM), 4- processed with ammonia (5.3% of DM) 5- processed with sodium hydroxide (5 % of DM), 6- processed with peroxide + sodium hydroxide (5% of DM sodium hydroxide + 2 % of DM hydrogen peroxide), 7- processed with water (71 % of DM). The rates of degradation of the treatments were evaluated in an in situ experiment using three non-lactating Holstein cows with average body weight of 670±15 kg. Experimental treatments were incubated intraruminally for 0, 3, 6, 12, 24, 48, 72 and 96 hours. Degradability parameters were calculated for dry matter, organic matter and cell wall by Neway software. In the second section were used 16 calves with average initial weight 266±64 kg to test the effect of straw processed on fattening performance of male Holstein calveswith average initial weight 266±64 kg. This experiment was conducted in a completely randomized design with two experimental diets and 8 replicates for each diet. This noitces was done in 90 day. Feed intake was measured daily and body weight was measured monthly. The results of the first section showed that canola straw processed with urea and urea + molasses had the highest CP percentage. Processing of canola straw with urea + molasses, sodium hydroxide and sodium hydroxide + peroxide significantly decreased the cell wall content. Processing with urea + molasses made significant difference in (a) parameter of DM and OM (p <0.05). Effects of processing with sodium hydroxide, sodium hydroxide + peroxide, urea and water on parameter of (b) for DM and OM were significant (p <0.05). On the base of present results, processing of canola straw with sodium hydroxide and sodium hydroxide + peroxide was suggested. The results of second part showed that the final weight, daily gain and feed conversion ratio was not significantly different in the both of calves groups.The dry matter intake in calves that fed with unprocessed canola straw was significantly less than calves fed processed. Results of the digestibility was not significant different between the two groups.