| Based on the case of lacking forage and feeding large quantity of corn stovers to sheep in Winter and early Spring in Inner Mongolia, the research tried to screen a kind of suitable and efficient supplement diets through five experiments: firstly, effects of different levels of supplement with corn on apparent nutrient digestibility, nitrogen and mineral balance in sheep fed corn stovers; secondly, effects of different levels of supplementing with corn on apparent nutrient digestibility, nitrogen and mineral elements balance in sheep fed corn stovers sprinkled with urea; thirdly, effects of different nitrogen resources on apparent nutrient digestibility , nitrogen and mineral elements balance in sheep fed corn stovers; fourthly, effects of different nitrogen resources (supplement mineral elements) on apparent digestibility of DM,OM,NDF and ADF, nitrogen and mineral elements balance in sheep fed corn stovers; lastly, effects of different combination of concentrates on production in sheep fed corn stovers. The results indicated: 1. The control group (feeded with stovers singly) was in negative nitrogen balance and appeared low apparent nutrient digestibility. The same condition happened on the mineral elements of Cu,Mn,Se and I .Among which Se and I wewe in serious negative balance. With the increasing supplementation of corn, the apparent digestibility of DM, OM and CP improved. The digestibility of NDF and ADF did not improved significantly. The availability of nitrogen and mineral elements inclined to increase, but it was not high in the whole and the difference between treatments were not obvious. 2. The digestibility of NDF and ADF did not change much before and after sprinkling urea. But the nidrogen balance of the control group changed from negative to positive. The group of 30% corn had the highest N availability and digestibility. They were 33% and 47% respectively and higher than groupâ… significantly. The negative balance of mineral elements was improved meanwhile. 3. In the condition of different nidrogen resources supplementing stovers, sunflower meal + cloza meal group had the highest digestibility of DM and OM, followed by cloza meal group. Both of them were significantly higher than sunflower meal group (â…¡) (p<0.05). The digestibility of NDF and ADF for sunflower meal + cloza meal group (â… ) were 65.2% and 59.9% respectively, and they were the highest too. Compared with group of single stovers, it increased by 14.3% and 18.7%. But the dif ferences between each group were not significantly (p > 0.05). The N availability of sunflower meal + cloza meal group (â… ) was 23% and obvious higher than sunflower meal group (â…¡)(8%) and cloza meal group (â…¢)(12%)(p<0.05). The same results for the Cu and Mn (p<0.05). But the differences among the other elements were not significantly (p> 0.05). All mineral elements availability were improved in different degree compared with the group of single stovers. The research demonstrated that in the condition of feeding rough fodder, the depradation of NDF and ADF could be increased efficiently through supplementing nitrogen resources into rumen. 4. The apparent nutrient digestibility of DM, OM, CP, NDF and ADF increased through supplementing mineral elements. This change was more significant for sunflower meal + cloza meal group and cloza meal group than sunflower meal group. Supplementing mineral elements additive had little effects on the absorbance of nitrogen. But the excretion of nitrogen in urine decreased obviously. As a result, the N retention increased apparently. N availability increased by 1%, 4% and 17% for 3 experimental group respectively. Mineral elements availability also increased obviously after supplementing the additive. The research proved that supplement of mineral elements increased not only availability of NDF, ADF and mineral elements but also apparent nutrient digestibility. 5. The weight of sheep increased significantly after supplementing the concentrate â…¡ designed in experiment 5. Compared with traditional supplementing with corn, the d...
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