Effect of grass species and different levels of maize bran on silage quality

摘要

Thecompositionoftropicalgrassesasfodderfordairycattleproduceslowqualitysilageswithouttheuseofadditives.Maizebranadditivehavebeenusedbysmallholderdairyfarmerstoimprovethequalityofsilages.However,theeffectofdifferentlevelsofmaizebranonvariousgrasssilagesqualityisrarelydocumented.Thisstudythereforewasconductedtoinvestigatetheeffectofgrassspeciesanddifferentlevelsofmaizebranonsilagequalityinsmallholderdairyfarms.Elephant(Pennisetumpurpureum),guatemala(Tripsacumlaxum)andrhodesgrasses(Chlorisgayana)wereestablishedandharvestedwhentheywereattheageof120,63and56daysrespectively.Nutritivevaluedeclinesquicklyasplantmaturesthuswereharvestedatrespectiverecommendedstagesofgrowthforeachgrass.Theharvestedgrasseswerechoppedinto4cmandsubdividedintofourportionseachofwhichwastreatedwithadifferentlevelofmaizebran(0,5,10,and15%).Thechoppedmaterialswereensiledinportionof5kginplasticbagsilo.Treatmentswereassignedtoacompletelyrandomizeddesigninfactorialarrangement(3x4)asthreegrasses(elephant,guatemalaandrhodesgrasses)andfourmaizebranadditivelevels(0,5,10and15%)withtworeplications.Thesilagewasopenedafter60days,sampledandanalyzedforchemicalcomposition,fermentation,sensoricqualitiesandinvitroDMdigestibility(IVDMD).Elephantgrassproducedhigherqualitysilagesthanthoseproducedbyguatemalaandrhodesgrassesasindicatedbyhighersensoricqualities,crudeprotein(CP),lacticacidandstabilitybutlowerpHandNH3N.Maizebranat10%levelproducedhigherqualityandpreservedbetterthanmaizebranat0,5and15%levelsasindicatedbyhighersensoricscores,CP,WSC,lacticacid,aceticacidandstabilitybutlowerNDF,pHandNH3N.Theinteractionbetweengrassspeciesanddifferentmaizebranlevelsshowedthat,elephantgrasssilagewithmaizebranat10%levelproducedbestsilageasindicatedbyhighestsensoricscores,CP,lacticacidandstabilitybutlowestpH.Therefore,elephantgrassmixedwithmaizebranat10%levelwasthemostoptimalcombinationtechniquestoachievehighqualitysilageundersmallholderfarmers.