| By assessing the nutritional value and determining the rumen degradation rate of 11 energy feeds,as well as screening by affiliation function,three feed ingredients were selected to replace some maize and design the feed formulations.The effect of the diet formulation on the feeding of Bohai black cattle was observed.Firstly,11 energy feeds were evaluated by conventional analysis and the Cornell Net Carbohydrate System（CNCPS）.Then the rumen degradation characteristics of the 11 feed ingredients were compared in fistulated cattle using the nylon bag method.Finally,through affiliation function screening,three feed ingredients were selected to replace some of the corn for feed formulation design,and a 2-month feeding trial was conducted on Bohai black cattle to study the effect of partial replacement of corn on growth performance and blood index of Bohai black cattle,and to provide data support for the improvement of diet formulation in the test cattle farm.Experiment 1: Study of the differences in the composition of 11 energy feedsIn this experiment,the conventional nutrient composition of rice bran meal,brown rice,wheat,and barley（Shandong Feed Industry Co.,Ltd.）was determined using the conventional analysis method,while the above feeds were analyzed for nutrient composition using the CNCPS method,and finally the predicted energy values were calculated using the National Research Council（NRC）.The results showed that soybean hulls had the highest content of neutral detergent fiber（NDF）and acid detergent fiber（ADF）,which was significantly greater than other energy-fed feeds（P < 0.05）.The crude protein（CP）content in descending order was: bran > secondary meal > rice bran meal > wheat > soybean hulls > rice bran >sorghum > barley > brown rice > corn > rice.The non-protein nitrogen（PA）content of maize,sorghum,rice,and brown rice was similar（P > 0.05）and significantly higher（P < 0.05）than other energy feeds.All energy feeds were significantly different（P < 0.05）except brown rice and barley,which had no significant difference（P > 0.05）.In fast degradable protein（PB1）content,rice bran had the highest PB1 content of 39.3%,significantly higher than other energy feeds（P < 0.05）;rice had the lowest PB1 content of 6.74%,significantly lower than other energy feeds（P < 0.05）.The non-structural carbohydrate（NSC）contents of all energy feeds were significantly different（P < 0.05）.Maize had the highest NSC content of 92.06%and soybean hulls had the lowest NSC content.The carbohydrate（CHO）content of maize,rice,and brown rice was similar（P > 0.05）and significantly higher（P < 0.05）than other energy feeds;rice bran had the lowest CHO content of only 59.81%.All the moderately degradable carbohydrates（CB1）of all energy feeds were significantly different（P < 0.05）,and maize had the highest CB1 content of 68.31%,which was significantly higher than other energy feeds（P < 0.05）.The highest TDN of maize was not significantly different from that of sorghum（P > 0.05）,but significantly higher than other energy feeds（P < 0.05）,and the TDN of rice bran meal was significantly lower than that of other energy feeds（P < 0.05）.Secondary flour,bran,bean skin and rice bran have high nutritional value and can be used as a substitute for corn to make a feed formula.Experiment 2: Ruminal degradation characteristics of 11 energy feedsIn this study,three Lucian and Limousin crossbred cows with permanent rumen fistula in good body condition and similar body weight were selected as test animals,and the rumen degradation characteristics and rumen degradation parameters of 11 energy feeds were analyzed by the nylon bag method for dry matter（DM）,NDF,ADF,CP,and crude fat（EE）.The results showed that the ruminal degradation rate of energy feeds increased with time,and the effective degradation rate of DM was bran > wheat > secondary meal > rice bran meal >corn > rice bran > soybean peel > rice > barley > brown rice > sorghum in descending order.The effective degradation rate of NDF rumen was significantly different（P < 0.05）for all energy feeds except for the effective degradation rate of NDF rumen of secondary flour and bran,which were not significantly different（P > 0.05）.The effective ADF degradation rate of bran was significantly higher than that of other energy feeds（P < 0.05）,and the effective ADF degradation rate of rice was significantly lower than that of other energy feeds（P < 0.05）.The effective degradation rate of CP of secondary flour,bran,wheat,and barley was not significantly different（P > 0.05）but significantly higher（P < 0.05）than other energy feeds,and the effective degradation rate of CP of sorghum was significantly lower（P < 0.05）than other energy feeds.The rumen degradation rate of the energy feed increased over time.Bran,secondary flour,rice bran and bean skin showed similar DM degradation rates with maize.Experiment 3: A Study on the Effect of Different Diets on the Growth Performance of Bohai Black CattleThe feed formulation was designed with one group replacing 10% maize（treatment group I）and another group replacing 20% maize（treatment group II）.For a two-month feeding trial,the 14 Bohai black cattle in each of the two treatment and control groups were fed roughage of rice straw and straw,and the treatment group was pre-fed for 7 days before the trial.The apparent digestibility of DM,CP and EE in treatment group two was significantly greater than that in control and treatment group one（P < 0.05）,but the ADF and NDF in the control group were significantly greater than those in treatment group two and treatment group one（P < 0.05）,and the daily weight gain of Bohai black cattle in treatment group two was the greatest.The new feed formulation had no effect on aspartate aminotransferase（AST）,alanine aminotransferase（ALT）,cardiac enzyme（CK）,glucose（GLU）,total protein（TP）and urea（UREA）in Bohai black cattle,but caused an increase in total cholesterol（TC）in Bohai black cattle.The fat deposition capacity of Bohai black cattle was enhanced.The new feed formulation had no effect on the immunity of Bohai black cattle,and only propylene glycol（MDA）was enhanced for antioxidant capacity.The new feed formulation had no effect on growth hormone（GH）,Insulinotropic growth factors（IGF-1）,insulin,glucagon,and cortisol.The 20% corn has the highest profit per cow at 20.86 yuan per day.In conclusion: this study proved that the feed formula of treatment the 20% maize replacement group is an alternative to the existing formula of Bohai Black cattle farm for feeding,which can improve the daily weight gain of Bohai Black cattle and improve the economic efficiency. |
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