Variation of the chemical composition of milk from Holstein cattle in North-East Algeria

摘要

TheobjectiveofthisstudywastoevaluatetheeffectoflactationnumberandseasononthechemicalcompositionofmilkHolsteinsduringlactationanalyzedatthewilayaofEl-tarf.Abreedingmonitoringdetailingdrivingmodescowswasadoptedinparallel,monthlysamplesofmilkmixturewereanalyzedfortheirchemicalproperties(butterfatandproteincontent).Ourresultsshowthatthenumberoflactationaffectsthevariationoftheparametersofmilk(FatandProteins).Therichestmilkisproducedbycows4thlactation(fat=32.7±0.79andproteins=33.2±0.11).Undertheeffectofseason,fatandproteinlevelswereminimalinwinter.Atimeofsignificantaccesstopastureisaccompaniedbyanimprovementinprotein(1.25g/lonaverageforthe4thlactationcowsand1.35g/lonaverageforcowssixthlactation).Similarly,fatcontentincreased(0.15g/lin4thlactationand0.65g/linthesixthlactation).Thisstudyallowsustoevidencethefavorableeffectofthefactorquot;alimetationquot;howeveritlikelythatthisfactorisnotwellcontrolled,asshownbythedecreaseinmilkfatandproteinlevelsinwinter.