Mineral status in beef cattle, live weight changes and immune response as related to selenium and vitamin E supplementation

摘要

Twoexperimentsonein1988andonein1989wereconductedtoevaluatethemineralstatusofgrazingcattleontwofarmsinnorthFlorida.Lymphocyteblastogenicresponse,liveweightgainandbodyconditionscoreswerealsoevaluatedinExperiment2asrelatedtothesupplementalSeandvitaminEprovidedinthisexperiment.InExperiment1serummineralconcentrationsofcowspresentedmonthlyvariations,whileincalvesmineralconcentrationsvariedasafunctionoflocationand/ormonthofsampling.InExperiment2serummineralconcentrationsforbothcowsandcalvesvariedsimultaneouslyasafunctionoflocationandsamplingmonth.Variationsinserumconcentrationswerenotconsistentfromyeartoyearorfromcowstotheircalves.WiththeexceptionofPforcowsinbothexperiments,andbasedonthemeanconcentrations,serummineralstatusofbothcowsandcalveswasconsideredadequateinbothexperimentswhichmaybeaccountedforbythefree-choiceconsumptionofmineralsupplementprovidedtoallanimals,sincesoilandforagedatashowedseveralmineralstobelowtodeficient.NeitherSenorvitaminEhadanyeffectonlymphocyteblastogenicresponsewithanyofthemitogensevaluated;however,thehealthstatusofcattlewasalsosatisfactoryonbothfarmsduringthetimetheexperimentwasconducted.CowslostweightfromMarchtoOctober,butBCSinOctoberwereslightlyhigherthaninMarch.SeleniumsupplementedcowsatWillistonweretheonlycowsgainingweightfromJune-OctoberandtheircalveshadhigherADGthancontrols.