Factors affecting pre and post-weaning growth of six cattle breed groups at Songa Research station in Rwanda

摘要

Theobjectiveofthisstudywastoassessthegrowthperformanceofsixcattlebreedgroupsfrombirthto18monthofageatSongaResearchStationinRwanda.Recordsofanimalsbornbetween1998and2008wereevaluatedusingnestedANOVAforeffectsofnon-geneticfactorsongrowthperformanceofdifferentcattlebreedgroups;comparegrowthrateofdifferentcattlebreedgroup;andidentifysuitablebreedgroupforSongaenvironment.TheanimalsusedinthestudyweretakenfromaherdofcrossbredsofAnkoledamswithBrownSwiss,Friesian,JerseyandSahiwalsires.Birthweightwasnotaffectedbybreedgroup,sexofthecalforenvironmentalfactors,suchasyearandseasonofbirth.HoweverthecalvessiredbyBrownSwissandFriesianswereheavierthancalvessiredbyJerseys.Atweaning,theeffectsofbreedgroup,yearofbirthandseasonofbirthwereallhighlysignificant(P0.001),aswastheeffectofnestingseasoninbreedgroups.WeanedcalvesofAnkole-Friesiancrosses(AF)weresignificantlyheavierthanthoseofallotherbreedgroupsexceptAnkole×BrownSwiss(AB)andAnkole×Sahiwal(AS)crossbreds.Theheaviestcalveswerebornduringseason4oftheyear,thoughweaningweightsacrossseasonsdidnotdiffersignificantly(P0.05).Maleweanedcalves(179.3±6.0kg)wereheavierthanfemaleweaners(164.6±9.9kg).AwiderangeofweaningweightforABandAFbreedgroupswereobserved,comparedwiththerangeofmeanweightsforAJ,AJS,AS,andASJsuggestingthatbreedgroupscontainingJerseyandSahiwalbloodaremoreresilienttoenvironmentpressure.Matureweightsofanimalswassignificantlyaffectedbybreedgroup(P0.01),sex(P0.001),andyearofbirth(P0.001)whileseasonanditsinteractionwithbreedgroup(P0.05)didnotinfluenceit.Generally,breedgroupABgrewfasterthanallotherbreedgroupswhilethelowestgrowthratewasregisteredinbreedgroupAS.However,thespeedofgrowthwassimilartothoseinbreedgroupsAJ,AJS,ASandAJS.WeobservethatAS,AJSandASJbreedgroupwasthebestbreedgroupfortheareaofstudyandthatthemajorfactorstoconsiderduringthebreedingofthevariousbreedgroupsincludesex,seasonofbirthandyearofbirth.Itisthereforerecommendedthattoattainthebestlevelofperformanceforthesecattle,artificialinseminationshouldbesynchronizedwithmaximumforageavailabilityatparturition.