Growth, carcass and behaviour characteristics of castrated and intact male grasscutters (Thryonomys swinderianus)

摘要

Fortyeight(48)maleandtwelve(12)femalegrasscutters,4-5monthsoldandweighingbetween0.69-1.94kgwereusedforthestudy.Themalegrasscuttersweredividedintotwo(2)groupsof0.69-1.00kgand1.18-1.94kgliveweights,constitutingtwoblocks(blocks1and2).Twelve(12)malegrasscuttersfromeachblockwererandomlyselectedandsurgicallycastrated.TheRandomizedCompleteBlockDesign(RCBD)wasused.Tofindtheeffectofcastrationongrowthandcarcasscharacteristics,twotreatments,namely,intactmales(IM)andcastrates(CS)wereused.Carcassevaluationwasconductedusingeight(8)intactmalesandeight(8)castratedgrasscutters.Tofindtheeffectofcastrationonbehaviourofgrasscutters,castratedand/orintactgrasscuttersweremixedinthesamecagewithorwithoutafemale.Thetreatmentgroupswereintactmalesonly(IM),castratesonly(CS),intactmalesandfemales(IMF),castratesandfemales(CSF),intactmalesandcastrates(IMCS),andintactmales,castratesandfemales(IMCSF).Castrationofgrasscuttersbetween4-5monthsofagecouldnotinfluencegrowthrate(P0.05)butledtoimprovedfeedutilization(P0.05).Aggressivebehavioursofgrasscuttersincolony,anddocilitywerealsonotinfluencedbycastration(P0.05).Intactmalesmixedwithcastratesonly(IMCS)andintactmalesmixedwithcastratesandfemales(IMCSF)co-existedpeacefullythantheothertreatments.nbsp;Carcassweight(hot/cold),dressingpercentages(hot/cold),fatdeposition,chemicalconstituentsofmeatandorganweightswerenotaffected(P0.05)bycastration.Sensorypanelistsidentifiedcookedgrasscuttermeatcolourstorangefromivorytoyellowlemonforforelegs,andivorytolightivoryforhindlegsandlongissimusdorsi.Bothintactmalesandcastratedgrasscuttermeatsweregenerallyacceptable(P0.05)bysensorypanelists.