Seasonal variations in sperm production, gonadal and extragonadal sperm reserves in pubertal West African dwarf bucks in their native tropical environment

摘要

Theeffectsofseasonondailyspermproduction(DSP),dailyspermproduction/gramtestis(DSPG),gonadalandextragonadalspermreservesinpubertalWestAfricanDwarfnbsp;(WAD)buckswereevaluatedusing8animals.BothDSPandDSPGdeterminedbyquantitativetesticularhistologyandfromtesticularhomogenatesweresimilar(P0.05)betweentherainyanddryseasons.Therewerenosignificantdifferences(P0.05)betweenthemethodsofevaluationinbothDSPandDSPG.Seasonlikewisehadnoeffect(P0.05)ongonadalandextragonadalspermreserves.TherewerenumericaldifferencesbetweentheseasonsinallparametersexceptinDSPGobtainedfromtesticularhistology.DSPwashighlysignificantlypositivelyrelatedtototalepididymalspermreserves(r=0.71;P0.001);caputreserves(r=0.82,P0.01);corpusreserves(r=0.82;P0.001);ductusdeferensreserves(r=0.85;P0.001)andgonadalspermreserves(r=0.90;P0.001).Totalepididymalreserveswerehighlycorrelatedwithcaput(r=0.90;P0.001);corpus(r=0.91;P0.001);cauda(r=0.90;P0.001);ductusdeferens(r=0.93;P0.001)andgonadal(r=0.82;P0.001)reserves.Therelationshipsbetweenallepididymalsectionsandgonadalspermreservesaswellasamongepididymalsectionswereallgood.ItisconcludedthattheWADbuckwouldnotbeaseasonalbreederinitsnativeenvironment.Semencouldthereforebeobtainedallyearroundfromsuperiorsiresforuseinplannedbreedingprogrammesaimedattheimprovementofthisbreed.Farmerscouldthenbenefitfromsuchprogrammesataffordablerates.