Feeding urea-molasses blocks reduced milk urea nitrogen in Iranian rural dairy cows

摘要

Theaimofthestudywastoinvestigatetheeffectoffeedingurea-molassesblocks(UMB)onmilkureanitrogen(MUN)andmilkproductioninruraldairycows.Inthefirstexperiment,physicalcharacteristics,palatabilityandintakeofsixdifferentUMBformulas(Allen2007,B1,B2,B3,B4andB5)werestudiedusingsixIranianruraldairycows.AveragedailyintakeofcowsfromAllen2007,B1,B2,B3,B4andB5blockswere450,655,283,615,170and272g,respectively.TheB1formulawasthebestasithadthebestphysicalqualityandthehighestintakebytheanimalsamongtheotherformulas.Inthesecondexperiment,effectsofsupplementingruraldairycowswithUMB(B1formula)onmilkyield,milkcompositionandmilkureanitrogen(MUN)wereinvestigated.SixcrossbredIranianruraldairycowsinacrossoverdesignhadeitherfreelyaccess(+UMB)ornoaccessto(#8211;UMB)urea-molassesblocksfrom30-50(P1)or70-90(P2)daysinmilk.Dailymilkproductionswerecontinuouslyrecordedforthreemonths.Milksamplesweretakenon45,50,85and90dayoflactationperiod.Resultshowedthat+UMBhadsignificantlyhigherdailymilkproductionincomparisonto#8211;UMBwith9.4and9.0kgrespectively.+UMBhadsimilarpercentageofmilkproteinandlactosebutsignificantlylowerfatandnon-fatsolidcontentcomparedto-UMB.nbsp;Milkureanitrogenin+UMBweresignificantlylowerthanin#8211;UMB(7.2vs.9.1mg.dl-1).Inconclusion,UMBimprovedmilkproductionpresumablyviamoreefficientuseofnon-proteinnitrogen(urea)whichisreflectedinlowerMUNinIranianruraldairycows