| Nowadays,the competition for food and land resources between human beings and animal husbandry is becoming more and more prominent.Under this scenario,the promotion of forages like sweet sorghum can not only improve the efficiency of marginal land utilization,but also can effectively alleviate the prominent contradiction between people andlivestock.Sweet sorghum is one of the highest biomass yielding cropsin the world,and is also considered as importantanimal foragein the world.However the current forage processing and modulation technology deficiencies hasseverely limited the sweet sorghum efficient utilizationas one kind of low-cost forage grass in animalfeedindustry.This situation has greatly hampered the development of forage sweet sorghum industry.Thisdissertation aims toimprove the processing and utilization of sweet sorghum in Gansu Province,and promote scientific and technological supports for the healthy development of sweet sorghum industry.This study was carried out throughsnowball sampling of 9 cities and 15 counties,200 households and 50 forage-farming factories in Longdong,Longzhong and Hexi areas in Gansu Province.This research studied the varieties of forage sweet sorghum in Gansu Province,their feed value and effects of sorghum feeding on livestock health.Five kinds of biological additives such as formic acid,cellulase,Lactobacillus brucei,Lactobacillus plantarum and biochar were added to the sweet sorghum(Monster)to determine conventional nutrients and fermentation quality of sweet sorghum silage.The digestion and degradation characteristics,total gas production,methane emission and fermentation kinetics parameters of sweet sorghum were also studied by artificial rumen method.The main research findings are as follow:(1)The dominant cultivars of sweet sorghum are Hercules,Monster and Big KahunainGansu province.Forage sweet sorghum has a good palatability,herbivorous animals extremely prefer to take.After feeding sheep with sweet sorghum forage,the greasy and smell of the mutton Sensory characteristics are the most intense feelings,which are key indicators for the further evaluation of the mutton quality.Meanwhile after feeding dairy cattle with forage sweet sorghum,the milk color and taste have changed to more better.(2)The highest dry matter recovery(87.75%)and crude protein content(9.41%)were obtained after adding formic acid to sweet sorghum silage.It also effectively reduced the crude ash content of silage and retained more water solublecarbohydrate(9.01%).The maximum gross energy(18.19 KJ/g)was obtained after adding the cellulase to Sweet sorghum silage.The lactic acid content(8.57%)was the highest after the addition ofLactobacillus plantarum.(3)Dry matter degradability of ensilaging sweet sorghum in vitro fermentation was the highest(61.01%)after formic acid treatment.The addition of Lactobacillus buchneriand formic acid during sweet sorghum silagesignificantly reduced methane gas emissions.The addition of formic acid treatment can increase the amount of gas produced in the fast fermentation(a),the fastest fermentation rate were obtained after adding Lactobacillus buchneri and formic acid.The maximum theory gas production(a+b)was positively correlated with the content of crude protein and crude ash,and the emission of methane was significantly and positively correlated with crude protein,neutral detergent fiber and crude ash.Gas production rate and crude protein content were found to be negatively correlated.(4)Addition of0.5% formic acid during sweet sorghum silage processing,not only significantly improved the quality of silage,but also reduced the methane emissions during in vitro fermentation,so moreproduction and ecological benefits.Therefore formic acid is provedanideal silage additive for sweet sorghum.(5)On the basis of the investigation and silage research,for the technical improvement of the enterprises,one processing technology of sweet sorghum wrapping silage and green hay production was built in Gan su area. |
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