Yield and quality of sweet potato forage pruned at different intervals for West African dwarf sheep

摘要

Inordertostudytheeffectofcuttingmanagementonyieldandqualityofsweetpotato(SP)foragegrownfordryseasonfeedingofsheep,SPvinesweresubjectedtofourcuttingregimes:pruningat4,6,8weeksintervalanduncutplots(control),usingarandomizedcompleteblockdesign.CutforageswerefedtotwelvematureWestAfricandwarf(WAD)sheepconfinedinmetabolicpensfor14daystodeterminethedigestibility.Drymatter(DM)yieldofforagewas8.6,12.0,12.2and8.1t/hawhilebiomassyieldwas12.9,17.0,18.1and17.0t/hafor4,6,8weekscuttingintervalandcontrolplotsrespectively.Crudeprotein(CP)contentoftheforagewas26.7,25.0,21.8and20.1%whileDMdigestibilitywas75.7,68.7,65.2and64.0%fortherespectivecuttingintervals.FrequentcuttingofSPvines(4weeksinterval)didnotsignificantly(P0.05)improveforageyieldwhereasrootyieldandtotalbiomassproductionweresignificantly(P0.05)depressed.Pruningatlongerintervals(6and8weeks)significantly(P0.05)improvedforageyieldattheexpenseofrootyield.Biomassproductionwashowever,notsignificantly(P0.05)affected.CPcontentofforageincreasedasfrequencyofcuttingincreasedwhilethefibrecontentreduced.DMandnutrientdigestibilityoftheforageimproved(P0.05)withmorefrequentcuttingofthevine.ThenumberofanimalssupportedbyonehectareofSPcropincreasedasintervalbetweencuttingsincreasedalthoughqualityofforagewascompromised.Pruningat6weeksintervaloptimizedtheyieldandqualityofSPforagefedtoWADsheep.