Assessment of various treatment conditions affecting the ammoniation of long straw by urea

摘要

Theeffectofmoisturelevel(trials1,2and3)andoftreatmentperiod(trial1)onthenutritivevalueofurea-treatedstraw(UTS)wasstudiedinvivoandinsacco.Intrial2,untreatedstraw(US)sprayedwithureasolutionpriortofeedingwascomparedwithUTSandUS.TheeffectofcoveringUTSwithpolyethylenesheetwasstudiedintrial4.WiththeexceptionofcrudeproteincontentthatwasgreaterinUTSthanUS,therewerenodifferencesbetweenUSandUTSforcrudefibre,ash,NDForADF.InvitrodigestibilityandinsaccodegradabilityweregreaterinUTSthanUS.Maximumimprovementwasattainedwiththefirstlevelofmoistureintrials1(200litres/tonne)and3(300litres/tonne),butintrial2,UTSat300litresmoisture/tonnehadgreaterdigestibilitythanUTSat200litresmoisture/tonne.AlthoughmaximumdigestibilityanddegradabilityofUTSwereobtainedinthesecondweekoftreatment,differencesbetweentreatmentperiodswerenotsignificant.TherewassuperiorityofUTSoverUSsprayedwithureapriortofeeding(trial2),aswellasbetweenUTScoveredandnon-covered(trial4)followingspraying.BasedonthefindingsofthepresentstudiesthefollowingrecommendationscanbemadeforstrawtreatmentunderMediterraneanconditions.Treatmenttimeof1-2weeksisrequiredduringsummermonths,andamoistureleveloffrom200to300litres/tonneissufficientformaximumresponse.CoveredUTSissuperiortonon-covered,andUTSisalsosuperiortourea-sprayingpriortofeeding.