Performance and carcass characteristics of hair sheep lambs finished on tropical pasture or rangeland and supplemented with maize

摘要

Inthetropicsandotherwarmseasonclimates,improvedcultivatedpastures(IP)providealternativegrazingmanagementcomparedtograzingtraditionalnativepasture(NP)forhairsheepproduction.Post-weaninghairsheepfeederlambsgrazedonIPwithenergysupplementationcanprovideanalternateforage-basedpasturefinishingoptioncomparedtotraditionalgrain-basedfinishingmethodsthatrelyuponahigh-costconcentratediet.Toevaluatealternativepasturefinishingmethods,DorperXSt.CroixWhitehair(DSTX)lambsweremanagedundertwotypesofpost-weaningalternativepasturefinishingsystemsandliveanimalperformanceandcarcasscharacteristicsweremeasuredduringthefallof2006and2007.Foreightmonthsafterweaning(120daysafterbirth),alllambsgrazedNPconsistingofguineagrass(PanicummaximumJacq.)andhurricanegrass(BoithrocloapertusaL.A.Camus).Followingpreconditioning,lambswerestratifiedbyweight(average27kg)andsexintotwotreatments(NPorIP)withthreereplications.AllNPwasofsimilarforagecompositioncontainingamixtureofguineagrassandhurricanegrass.Improvedpastureconsistedofamixtureofseededtropicallegumesincludingcowpea(VignaunguiculataL.Walp.,cv#8216;Ironandclay#8217;),bluepea(ClitoriaterneteaL.,cv.Tehuana),lablab(LablabpurpureusL.Sweet,cv.Rongai),volunteerdesmanthus(DesmanthusvergatusL.Wild.),andvolunteerguineagrass.Alllambsweresupplementedwithmaize(ZeamaysL.)dailyatarateofonepercentoftheirbodyweightfor100daysandslaughteredatapproximately365daysofage.nbsp;ImprovedpasturelambshadgreatertotalweightgainthanNPlambs(11.1vs.7.6kg,respectively).Inaddition,IPlambshadhigheraveragedailygain(ADG)thanNPlambs(114vs.73.3g/day,respectively).IPlambscomparedtoNPlambswereheavieratslaughter(39vs.35kg,respectively),hadheavierchilledcarcassweights(19vs.16kg,respectively),andgreaterdressingpercent(50vs.47.8percent,respectively).Further,IPlambshadgreaterlegcircumference(43.9vs.41.6cm),increasedbodywallthickness(14.4vs.10.8mm),andlargerloineyearea(12vs.10.1cm2)comparedtoNPlambs.BackfatthicknesswasgreaterforIPcomparedtoNPlambsat3.33and2.66mm,respectively.TheIPlambsalsohadgreaternbsp;kidney/pelvicfatthanNPlambs(696vs.530g,respectively).Resultsofthisstudyindicatethattheadoptionofalternativepasturefinishingpracticesutilizingimprovedpasturewithcultivatedforagelegumesandmaizesupplementationcanleadtoimprovementsinanimalperformance,carcassmuscularity,andbeneficialfataccumulationofcrossbredhairsheeplambsundertropicalconditions.