Evaluation Of Maize Straw And Alfalfa Feeding Quality And It’s Database Construction

For thousands of households in the representative farming districts of Gansu province,raising zones and feedlots are the main beef cattle production systems.Forage and feed hybridization are the two crucial factors in the system.The efficiency and economy of the system can be maximized through i)improving the utilization and quality of forage resources;ii)establishing the nutritional content and quality using a rapid analysis platform;and iii)evaluating and optimizing the cross-breeding systems for beef cattle production.This study focused on the corn silage ensiling process,the cultivation and harvesting of alfalfa,beef cattle economic hybridization,and the development of a rapid detection method for measuring nutrient concentrations and digestibility（quality）of corn silage and alfalfa hay,to optimize the beef cattle production system in the representative farming districts of Gansu province.The results are as follows:1.Effects of different inoculants and delayed ensiling on the quality of corn silageThe delay of ensiling corn for silage by three days（3d）can reduce dry matter loss of silage with corn and without corn by 21.79%and 48.37%,respectively.All three inoculants reduced dry matter loss of corn silage.Sila-Max reduced dry matter loss of silage with and without corn grain by 33.72%and 45.80%respectively during a one-time ensiling treatment.The subsequent study demonstrate that Sila-Max and Sila-Max+wheat bran reduced dry matter loss of silage with and without corn grain by46.57%and 36.48%,respectively,using a 3d ensiling protocol.While both Sila-Max and Sila-Mix demonstrated the potential of improving fermentation quality of silage with and without corn grain,Sila-Max was the better inoculant for fermentation quality,while the Silia-Mix was the better inoculant for the aerobic stability.It was shown that the inoculation with both Sila-Max and Sila-Mix enhanced the quality and reduce the dry matter loss of corn silage,and especially using an inoculant with wheat bran during the ensiling of silage without corn grain is beneficial.2.Evaluation of different combinations of five strains of LAB with CaCO₃,enzyme,and urea for ensiling corn silageAn inoculant using a combination of five strains of LAB with CaCO₃ for ensiling corn silage was shown to increase the lactic acid and especially acetic acid concentrations to prevent silage pH from dropping excessively low while improving the nutritional quality.The inoculant of urea plus the LAB combination increased the acetic acid and NH₃-N concentration.The inoculant of cellulase,amylase and the LAB combination increased water soluble carbohydrate,lactic acid and acetic urea,cellulase,amylase and the LAB combination demonstrated the greatest improvement in fermentation and nutritional quality.3.The calibration and prediction of visual and near infrared reflectance spectroscopy（Vis/NIR）model for measuring the nutritional and fermentation quality of corn silageIn order to establish a rapid prediction model of the nutritional and fermentation quality index using Vis/NIR,74 corn silage samples were scanned before and after drying and grinding.The results show that the model established by the wet samples has an external error validation relative percent deviation（RPD）>3 for acid detergent fiber,neutral detergent fiber,lignin,water soluble carbohydrate,in vitro true dry matter digestibility of 24,30 and 48 hours.In addition the model can be applied to the actual detection of ash,starch,calcium and lactic acid concentrations,while its accuracy should be enhanced for external error validation RPD>2.The model was not useful for dry matter,crude protein,ether extract,phosphorus,acetic acid,NH₃-N,NH₃-N/TN and pH because the external error validation RPD<2.The model,which was established by drying and grinding samples,had a good prediction capacity for all16 nutritional indexes except for ether extract phosphorus and pH,（external error validation RPD>3）.4.Study on the dynamic changes of biomass and nutrient composition of two alfalfa varieties with different seeding methodsThe SK3010 variety demonstrated higher growth and yields of alfalfa hay during the earlier stage than the Golden Empress variety,while the mixed sowing group demonstrate significant（P<0.05）advantages in yield and crude protein production,but showed a relative decrease in feeding quality in the late growth stage.The nutrient concentration and feeding quality changed considerably during different growth stages with crude protein concentrations and feeding quality decreasing with growth stage（maturity）,while yield increased significantly（P<0.05）.The first cutting is the most important for the alfalfa production,and the research data support the recommendation to move harvest a week earlier for the first cutting to increase the time for the third crop growth to improve annual yields.5.The calibration and prediction of Vis/NIR model for measuring the nutrient composition of alfalfa hayOne hundred and sixty alfalfa samples（120 for calibration and 40 for validation）were scanned by Vis/NIR to establish a prediction model for nutritional composition.The model can be used to predict the crude protein,acid detergent fiber,neutral detergent fiber,calcium,phosphorus,ash,lignin and in vitro digestibility concentrations（external error validation RPD>2）,but not for ether extract and water soluble carbohydrate concentrations（external error validation RPD<2）.6.The fattening performance and meat quality of the offspring produced through commercial crossbreeding with Simmental beef cattleThe average daily gain of Wagyu×Simmental and Angus×Simmental cross bred beef cattle was improved by 6.4%and 4%,respectively,but dry matter intake and feed conversions were lower when compared to pure bred Simmental cattle during fattening period,which appears to be due to heterosis.This dressing percentage,pure meat percentage,marbling score,and backfat thickness of Wagyu×Simmental and Angus×Simmental crossbreds were improved by 5.29%,6.62%,7.24%,10.53%and2.66%,2.41%,5.87%,17.10%（P>0.05）,respectively compared to Simmental.The carcass dressing percentage of Wagyu×Simmental hybrid and the loin eye muscle area of Angus×Simmental crossbreds were improved by 1.34%（P>0.05）and 4.82%（P>0.05）,the fat weight decreased by 4.37%（P>0.05）and 26.23%（P<0.05）respectively compared to Simmental.The PUFA/SFA and MUFA/SFA of the two crossbreeds were higher（P>0.05）than Simmental,and the MUFA/PUFA and n6/n3PUFA were lower（P<0.05）than Simmental.In summary,this work demonstrates that the improvement in forage nutrient concentrations and quality can be improved through the ensiling process by using LAB to increase nutrient supply to the animal.The Vis/NIR can be used to determine nutrient composition and quality of forages,be it corn silage or alfalfa hay for feeding to livestock and finally the use of cross breeding beef cattle can improve feed conversions,average daily gains,carcass yields,and meat quality.