comparison of different antimicrobial sequences …125 nursery pig nutrition and management adding...

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Nursery Pig Nutrition and Management

Comparison of Different Antimicrobial Sequences on Nursery Pig Performance and Economic Return

M.U.Steidinger1,M.D.Tokach,D.Dau2,S.S.Dritz3,J.M.DeRouchey,R.D.Goodband,andJ.L.Nelssen

SummaryAtotalof1,008weanlingpigs(12.0lband19dofage)wereusedina42-dexperimenttocomparedifferentantibioticregimensongrowthperformanceandeconomicreturn.Fromd0to11andd11to21,pigswerefeddietscontainingnoantibiotic,acombina-tionofDenagard(NovartisAnimalHealth,Greensboro,NC)at35g/tonandchlortet-racyclineat400g/ton(Denagard/CTC),orPulmotil(Elanco,Greenfield,IN;363g/tonfromd0to11and181g/tonfromd11to21).Fromd21to42,pigspreviouslyfedDenagard/CTCorPulmotilwerefeddietscontainingnomedication,Denagard/CTC,oracombinationofMecadox(PhilbroAnimalHealthCorp.,RidgefieldPark,NJ)at25g/tonandoxytetracyclineat400gperton(Mecadox/OTC).AddingDenagard/CTCorPulmotiltothedietfromd0to11andd11to21improved(P <0.01)ADG,ADFI,F/G,andincomeoverfeedcost(IOFC).Therewerenodifferences(P >0.21)inADGorADFIbetweenpigsfedDenagard/CTCandpigsfedPulmotil;however,pigsfedDenagard/CTCtendedtohavebetter(P<0.09)F/Gfromd0to21.Feedcostwasalsolower(P <0.01)andIOFCwasgreater(P <0.03)fromd0to21forpigsfedDenagard/CTCthanforpigsfedPulmotil.AddingDenagard/CTCorMeca-dox/OTCtothedietfromd21to42increased(P <0.05)ADG,ADFI,andIOFCcomparedwithfeedingnoantibiotic,buttherewerenodifferences(P >0.17)inpigperformanceorIOFCbetweenpigsfedDenagard/CTCandMecadox/OTC.Fortheoveralltrial,addingantibioticstothedietduringanyphaseimproved(P <0.05)ADG,ADFI,F/G,andIOFC.Theseresultsdemonstratethataddingantibioticstothenurs-erydietimprovedpigperformanceandeconomicalreturnonthiscommercialfarm.

Keywords:antimicrobial

IntroductionPastresearchhascontinuallydemonstratedthatincludingantibioticsinnurserypigdietsimprovespiggrowthperformance(Hays,19784;Zimmerman,19865;Cromwell,

1SwineNutritionServices,Inc.,Anchor,Il.2NovartisAnimalHealth,Greensboro,NC.3DepartmentofDiagnosticMedicine/Pathobiology,KansasStateUniversity.4Hays,V.W.1978.Effectivenessoffeedadditiveusageofantibacterialagentsinswineandpoultryproduction.ReporttotheOfficeofTechnologyAssessment.U.S.GovernmentPrintingOffice,Wash-ington,DC.5Zimmerman,D.R.1986.Roleofsubtherapeuticlevelsofantimicrobialsinpigproduction.J.Anim.Sci. 62(Suppl.3):6-17.

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20016;Dritzetal.,20027;Steidingeretal.,20088).Thegreatestresponseisnormallythroughanincreaseinfeedintake,whichincreasesdailygain.Althoughthebenefitofincludingfeed-gradeantibioticsinthenurserystageiswelldocumented,limiteddataareavailablecomparingvariousantibioticregimensfornurserypigs.Inthe2008SwineDayReportofProgress(Steidingeretal.,2008),wereportedbeneficialresponsestoantibioticsfedinnurserypigdiets.Inthatstudy,wecomparedpigsfeddifferentregi-mensandcombinationsincludingDenagard(NovartisAnimalHealth,Greensboro,NC)andchlortetracycline(Denagard/CTC)withpigsfedMecadox(PhilbroAnimalHealthCorp.,RidgefieldPark,NJ)andoxytetracycline(Mecadox/OTC).Anyoftheantibioticregimenstestedimprovedgrowthperformanceandincomeoverfeedcost(IOFC)comparedwithpigsfednoantibiotic.Infact,removingantibioticsfromthedietduringanyphaseresultedinlowerIOFC.Therefore,thepurposeofthistrialwastovalidatetheresponsetoantibioticsobservedinourearlierstudy(Steidingeretal.,2008)andtocomparethegrowthandeconomicresponseofsomedifferentantibioticregi-mensthatarecommonlyusedinthecommercialswineindustry.

ProceduresAtotalof1,008pigs(12.0lband19dofage)wereusedina42-dexperiment.PigswerefromaPRRSvpositive,butstable,pigflow.ThepigflowhadahistoryofbothentericandrespiratorychallengewithavarietyoforganismsinvolvedincludingPasteurella multocida.Denagard/CTCwasselectedasoneoftheinterventionsbasedonthediag-nostichistory.Pigswereweanedintoa4-roomnurseryfacility.Eachroomcontained12pens(6×10ft)withwireflooringandasinglebowlwatererand4-holedryfeeder.Allpigsreceivedthesame3-stagediets(d1to10,10to21,and21to42;Phases1,2,and3,respectively);feedmedicationwastheonlydifferencebetweentreatmentgroups(Table1).

Theresearchsitehadafinishingbarnwithin75ftofthenurserybuilding.Historicalmortalitywas2%to10%,withpigsseroconvertingtoPRRSvbywk3inthenursery.PigswerevaccinatedforMycoplasma hyopneumoniaeandreceived½dosecircovirusvaccineat2and4wkpostplacement.

Allpigswereweanedonthesamedayandblockedbyweightintoeachofthetreatmentgroups.Therewere7treatmentgroups(144pigspertreatment;1,008pigstotal);eachtreatmentgroupconsistedof6or7penswith21pigsperpen.Allpigsweremonitoreddaily,andanimalsexhibitingsevereclinicalsignswerehumanelyeuthanizedaccordingtoNovartisAnimalHealthanimalwelfarepolicy.

Dietarytreatmentswerearrangedasa2×3factorialdesignplusanegativecontrol(Table2).Thenegativecontroldidnotcontainantibioticsduringanyperiod.Forthefactorial,pigsreceivedeitherDenagard/CTCorPulmotil(Elanco,Greenfield,IN)fromd0to10andd10to21andthen1of3dietsfromd21to42(negativecontrol,Denagard/CTC,orMecadox/OTC.WhenDenagard/CTCwasfed,Denagardwas

6Cromwell,G.L.2001.Antimicrobialandpromicrobialagents.Pages401-426inSwineNutrition.A.J.LewisandL.L.Southern,eds.CRCPress,NewYork.7Dritz,S.S.,M.D.Tokach,R.D.Goodband,andJ.L.Nelssen.2002.Effectsofadministrationofanti-microbialsinfeedongrowthrateandfeedefficiencyofpigsinmultisiteproductionsystems.J.Amer.Vet. Med.Assoc.220:1690-1695.8Steidingeretal.,SwineDay2008,ReportofProgress1001,pp.74-81.

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addedat35g/tonandCTCat400g/ton.ForMecadox/OTC,Mecadoxwasincludedat25g/tonandOTCat400g/ton.WhenPulmotilwasfedduringthefirst2phases,itwasincludedinthedietat363g/tonduringPhase1and181g/tonduringPhase2.

Waterandfeedwereavailabletoallpigsadlibitumforthedurationofthestudy.Feedsampleswerecollectedfromthefeedmilltoconfirmmedicationlevelforalldietphasesandtreatmentgroups.Feedsamplesalsowerecollectedfrom1feederofeachtreatmentgroupforalldietphases.Allfeedsampleswereanalyzedfortheappropriatemedicationanditsconcentration(Table3).

Allpigswereweighedond0,11,21,and42tocalculateADG,ADFI,andF/G.Anypigstreatedforhealth-relatedproblemswererecordedtocalculatethenumberoftreat-mentsperpen.Actualfeedcostatthetimeoftheexperimentwasusedtocalculatefeedcostperpigandfeedcostperpoundofgain.Incomeoverfeedcostwascalculatedaspoundofgain×thevalueofthegain-feedcostperpig.Twodifferentvaluesofgain($0.50/lbor$1.00/lb)wereusedtoaccountfortheimpactofweightgainedinthenurseryonpigweightatmarket.The$0.50/lbassumesthatweightgainedinthenurs-eryremainsatmarketwithoutbecominggreaterorsmaller.The$1.00/lbassumesthateach1lbgainedinthenurserybecomes2lbatmarket.Previousresearchhasdemon-stratedthateach1lbgainedinthenurseryisworth1to4lbatmarketdependingontheresearchtrial(Tokachetal.,19959;Steidingeretal.,2008).

DatawereanalyzedusingtheMIXEDprocedureofSAS(SASInstituteInc.,Cary,NC)withpenastheexperimentalunitforallresponsecriteria.Thestatisticalmodelincludedthefixedeffectoftreatmentandrandomeffectofnurseryroom.Thedatawasderivedfrom6or7replicatepensacross4nurseryroomsinabalancedincompleteblockdesign.SingledegreeoffreedomcontrastswereusedtodeterminetheresponsetoantibioticinclusioninthedietduringeachphaseandanydifferencesbetweenDena-gard/CTCandPulmotilduringPhases1and2andbetweenDenagard/CTCandMecadox/OTCduringPhase3.

Results and DiscussionNoadverseeffectstoinclusionoftheantibioticsinthefeedwerenotedduringanyphaseofthestudy.Overallpigmortalityduringthestudywassimilartohistoricalexpectedmortality.Laboratoryanalysisconfirmedantibioticinclusioninthetestdiets(Table3).AnalyzedlevelsinthefeedwerelowerthantargetedlevelsforCTCandDenagardbuthigherthantargetforOTC.ThelowlevelsofOTCinthecontroldietswereunexpected.Thereasonmayhavebeencontaminationduringsampling.Wedon’tbelievethecontaminationoccurredhroughfeedmixingbecausefeedbatcheswithoutantibioticweremanufacturedbeforebatcheswithantibiotictominimizeanypotentialforcarryover.ThereasonforthediscrepancyinOTCandCTClevelsinthePhase3dietsisalsounknown.Thetargetlevelwas400g/ton,buttestingresultsrevealed803g/tonforOTCand279g/tonforCTC.

9Tokach,M.D.,J.E.Pettigrew,L.J.Johnston,M.Overland,J.W.Rust,andS.G.Cornelius.1995.Effectofaddingfatand(or)milkproductstotheweanlingpigdietonperformanceinthenurseryandsubsequentgrow-finishstages.J.Anim.Sci.73:3358.

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AddingDenagard/CTCorPulmotiltothedietfromd0to11andd11to21improved(P <0.01)ADG,ADFI,F/G,andIOFC(Tables4,5,and6).AddingDena-gard/CTCtothedietalsolowered(P <0.03)feedcostperpoundofgainduringbothphases,whereasfeedingPulmotilresultedinasimilar(P >0.22)feedcostperpoundofgaincomparedwiththecontrol.PigsfedDenagard/CTChadlower(P <0.01)feedcostperpigandfeedcostperpoundofgainandhigher(P <0.03)IOFCthanpigsfedPulmotilfromd0to21(Phases1and2).IncludingDenagard/CTCinthedietfromd0to21afterweaningresultedin4.1lbmoreweightgainperpigandanetincreaseinIOFCof$1.35/pigwhengainwasvaluedat$0.50/lband$3.46/pigwhenthevalueofgainwasincreasedto$1.00/lb.IncludingPulmotilinthedietfromd0to21resultedin3.5lbmoreweightgainperpigthanthecontrolandanetincreaseinIOFCof$0.71/pigor$2.47/pigwhenvaluedat$0.50and$1.00/lb,respectively.Thus,Dena-gard/CTCresultedinweightgainsimilartothatofPulmotil,butwithagreaterIOFC($0.64/pigto0.99/pigdependingonthevalueofgain).

Addingantibioticstothedietfromd21to42improvedADG(P <0.01)andADFI(P =0.02)andtendedtoimproveF/G(P =0.08).Therewerenodifferencesinperfor-mance(P >0.46)betweenpigsfedDenagard/CTCandpigsfedMecadox/OTC.Althoughaddingantibioticstothedietincreased(P <0.01)feedcostperpigandfeedcostperpoundofgain,theweightgainbenefitresultedinincreased(P <0.01)IOFCwhenantibioticswereaddedtothediet.PigsfedMecadox/OTChadlower(P =0.03)feedcostperpoundofgainthanpigsfedDenagard/CTC;however,therewerenodifferences(P >0.17)betweenthetwoantibioticsforIOFC.ItisunknownwhethertheresponseinthisphasemayhavebeeninfluencedbythehighertestedOTClevelintheMecadox/OTCtreatmentrelativetotheCTClevelintheDenagard/CTCtreatment.ThereasonthatwebelievethattheantibioticlevelmayhaveinfluencedtheresponseisthatpigsfedDenagard/CTCtendedtogrowfasterthanpigsfedMecadox/OTCwhencomparedwiththesameantibioticcombinationsusedduringthePhase2periodinourpreviousstudy(Steidingeretal.,2008).

Fortheoveralltrial,addingantibioticstothedietfromd0to11,11to21,and21to42improved(P <0.05)ADG,ADFI,andF/G.Overallfeedcostperpigwasincreased(P <0.01)bytheadditionofantibioticstothedietduringanyphase.Addingantibiot-icstothedietalsoincreased(P <0.04)overallfeedcostperpoundofgain;however,overallIOFCwasincreased(P <0.04)whenantibioticswereaddedtothedietfromd0to21andd21to42.Theseresultsconfirmtheresultsofourfirstexperiment(Steidingeretal.,2008)thataddingantibioticstothenurserydietimprovedpigperfor-manceandeconomicreturnsonthiscommercialfarm.

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Table 1. Composition of control dietsItem Phase1 Phase2 Phase3Ingredient,%Corn1 42.62 41.21 40.37Soybeanmeal(46.5%CP) 23.52 30.79 25.47Wheypermeate 20 7.5 ---Drieddistillersgrainswithsolubles 2.5 15 30Spray-driedanimalplasma 3.65 --- ---Menhadenfishmeal 3.35 --- ---Fat,AVblend 1.501 2.077 1.425Limestone 0.673 1.076 1.275MonocalciumP,21%P 0.424 0.702 0.052Salt 0.25 0.25 0.4L-lysineHCl 0.371 0.450 0.458DL-methionine 0.205 0.154 0.072L-threonine 0.127 0.114 0.089Zincoxide 0.375 0.25 ---Vitaminpremix2 0.15 0.15 0.125Tracemineralpremix3 0.125 0.125 0.125Coppersulfate 0.075 0.075 0.075Sweetener 0.025 0.025 ---Phytase1200 0.0625 0.0625 0.0625Total 100.00 100.00 100.00

CalculatedanalysisSIDlysine4,% 1.45 1.36 1.25Totallysine,% 1.58 1.52 1.41SIDaminoacidratiosMet&Cys:lysine,% 59 60 57Threonine:lysine,% 61 61 60Tryptophan:lysine,% 17 17 17Valine:lysine,% 63 67 66ME,Kcal/lb 1,544 1,546 1,488Lactose,% 16.0 6.0 ---Phytase,units/kg 680 680 680CP,% 21.8 22.9 21.8Fat,% 4.1 5.8 5.3Ca,% 0.71 0.70 0.7P,% 0.68 0.63 0.64AvailableP,% 0.55 0.45 0.351Antibioticsreplacedcorninthecontroldietstoformtheexperimentaltreatments.2Providedfollowingvitaminsperpoundofcompletediet:vitaminA,4,995IU;vitaminD750IU;vitaminE,24IU;vitaminK,2.0mg;vitaminB12,17.6ug;niacin,22.5mg;pantothenicacid,12.5mg;andriboflavin,3.8mg.3Containedthefollowingminerals:copper,1.32%;iodine,240ppm;iron,10%;manganese,2.8%;selenium,240ppm;andzinc,12%.4Standardizedilealdigestible.

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Table 2. Dietary antibiotics in each phaseTreatment d0to11 d11to21 d21to42

1 Nomedication Nomedication Nomedication2 Denagard/CTC1 Denagard/CTC Denagard/CTC3 Pulmotil,363g Pulmotil,181g Denagard/CTC4 Denagard/CTC Denagard/CTC Nomedication5 Pulmotil,363g Pulmotil,181g Nomedication6 Denagard/CTC Denagard/CTC Mecadox/OTC2

7 Pulmotil,363g Pulmotil,181g Mecadox/OTC1Chlortetracycline,400g/ton.2Oxytetracycline,400g/ton.

Table 3. Analyzed antibiotic levels in each phase, g/tonCarbadox Oxytetracycline Chlortetracycline Tiamulin Pulmotil

Phase1Control 1.53 8.49 <0.91 0 <45.4Denagard/CTC1 --- --- 298 10.1 ---Pulmotil --- --- --- --- 295Phase2Control 2.25 5.28 <0.91 0 <45.4Denagard/CTC --- --- 379 20.3 ---Pulmotil --- --- --- --- 181Phase3Control <1.14 36.1 2.76 0 <45.4Mecadox25g/OTC2 13.4 803 --- --- ---Denagard/CTC --- --- 279 17.5 ---1Chlortetracycline,400g/ton.2Oxytetracycline,400g/ton.

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Table 4. Influence of antimicrobial additions to the diet on pig performance1

Treatment1 2 3 4 5 6 7

d0to10: Nomed Den/CTC2 Pulmotil Den/CTC Pulmotil Den/CTC Pulmotild10to21: Nomed Den/CTC Pulmotil Den/CTC Pulmotil Den/CTC Pulmotild21to42: Nomed Den/CTC Den/CTC Nomed Nomed Mec/OTC3 Mec/OTC SEM

d0to11ADG,lb 0.19 0.32 0.31 0.31 0.30 0.33 0.30 0.024ADFI,lb 0.30 0.39 0.38 0.41 0.39 0.41 0.41 0.023F/G 1.59 1.26 1.26 1.33 1.33 1.28 1.35 0.085d11to21ADG,lb 0.50 0.76 0.74 0.80 0.73 0.79 0.74 0.50ADFI,lb 0.77 0.99 1.01 1.01 0.97 1.01 0.98 0.77F/G 1.63 1.31 1.38 1.26 1.33 1.29 1.33 1.63d21to42ADG,lb 0.93 1.03 1.06 0.92 0.93 1.05 1.11 0.06ADFI,lb 1.43 1.62 1.59 1.46 1.49 1.59 1.64 0.106F/G 1.56 1.57 1.49 1.58 1.59 1.52 1.48 0.048d0to21ADG,lb 0.34 0.53 0.51 0.54 0.51 0.55 0.51 0.035ADFI,lb 0.52 0.68 0.68 0.70 0.66 0.70 0.67 0.037F/G 1.60 1.29 1.35 1.28 1.33 1.28 1.34 0.044d0to42ADG,lb 0.63 0.78 0.78 0.73 0.72 0.80 0.81 0.043ADFI,lb 0.98 1.14 1.12 1.07 1.07 1.14 1.14 0.065F/G 1.57 1.47 1.44 1.47 1.50 1.44 1.43 0.037Weight,lbd0 12.4 11.9 11.8 12.1 12.2 11.8 11.7 1.02d11 14.5 15.4 15.2 15.5 15.5 15.5 15.1 1.17d21 19.6 23.1 22.6 23.5 22.8 23.3 22.6 1.61d42 39.4 44.9 44.8 42.7 42.4 45.4 45.8 2.60Survival,% 95.8% 96.3% 99.3% 100.0% 99.3% 99.3% 98.0% 1.3%1Eachmeanrepresents6(treatment1)or7penswith21pigsperpenforatotalof1,008pigs.2Denagard,chlortetracycline.3Mecadox,oxytetracycline.

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Table 5. Influence of antimicrobial additions to the diet on feed economics1

Treatment1 2 3 4 5 6 7

d0to10: Nomed Den/CTC2 Pulmotil Den/CTC Pulmotil Den/CTC Pulmotild10to21: Nomed Den/CTC Pulmotil Den/CTC Pulmotil Den/CTC Pulmotild21to42: Nomed Den/CTC Den/CTC Nomed Nomed Mec/OTC3 Mec/OTC SEM

Feedcost,$/pigd0to11 0.73 1.02 1.19 1.06 1.22 1.06 1.26 0.068d11to21 0.98 1.39 1.58 1.41 1.52 1.42 1.53 0.086d21to42 2.95 3.81 3.74 3.01 3.07 3.60 3.70 0.234d0to21 1.70 2.41 2.76 2.47 2.73 2.48 2.78 0.141d0to42 4.68 6.21 6.42 5.47 5.78 6.07 6.46 0.329Feedcost,$/lbgaind0to11 0.351 0.296 0.358 0.313 0.377 0.302 0.38 0.021d11to21 0.205 0.183 0.216 0.177 0.209 0.181 0.209 0.007d21to42 0.153 0.176 0.167 0.155 0.156 0.163 0.159 0.005d0to21 0.250 0.219 0.261 0.217 0.259 0.218 0.265 0.009d0to42 0.179 0.191 0.198 0.179 0.192 0.182 0.192 0.004Incomeoverfeedcost1,$/pig4

d0to11 0.33 0.73 0.48 0.66 0.46 0.75 0.41 0.099d11to21 1.53 2.42 2.10 2.58 2.13 2.51 2.15 0.179d21to42 6.78 7.00 7.40 6.61 6.74 7.42 7.91 0.43d0to21 1.84 3.13 2.55 3.25 2.59 3.26 2.51 0.251d0to42 8.57 10.07 9.84 9.85 9.30 10.65 10.35 0.604Incomeoverfeedcost2,$/pig4

d0to11 1.39 2.48 2.14 2.38 2.12 2.57 2.07 0.226d11to21 4.04 6.22 5.77 6.58 5.77 6.44 5.84 0.435d21to42 16.51 17.80 18.55 16.24 16.55 18.44 19.52 1.054d0to21 5.38 8.69 7.83 8.96 7.88 8.99 7.77 0.612d0to42 21.83 26.35 26.10 25.16 24.38 27.38 27.16 1.4941Basedietcostswere$442.60/tonfromd0to11;$252.31/tonfromd11to21;and$196.63/tonfromd21to42.Medicationcostspertonwere$27.85forDenagard/CTC(Den/CTC),$18.65forMecadox/OTC(Mec/OTC),and$122.54for363gofPulmotil($61.77for181gofPulmotil).2Denagard,chlortetracycline.3Mecadox,oxytetracycline.4Incomeoverfeedcost1assumedavalueofgainat$0.50/lb.Incomeoverfeedcost2assumedavalueofgainof$1.00/lb.

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Table 6. Statistical differences for performance and economic data, (P<)Contrasts1

1 2 3 4 5 6 7 8d0to11ADG,lb <0.01 <0.01 <0.01 0.32 0.01 0.04 0.03 0.90ADFI,lb <0.01 <0.01 <0.01 0.55 0.07 0.29 0.04 0.36F/G <0.01 <0.01 <0.01 0.67 0.02 0.02 0.10 0.45d11to21  ADG,lb <0.01 <0.01 <0.01 0.21 0.04 0.10 0.05 0.77ADFI,lb <0.01 <0.01 <0.01 0.66 0.05 0.09 0.10 0.96F/G <0.01 <0.01 <0.01 0.16 0.05 0.16 0.05 0.57d21to42  ADG,lb 0.09 0.19 0.05 0.32 <0.01 0.01 <0.01 0.46ADFI,lb 0.15 0.20 0.15 0.80 0.02 0.05 0.03 0.86F/G 0.66 0.94 0.45 0.30 0.08 0.27 0.07 0.48d0to21  ADG,lb <0.01 <0.01 <0.01 0.21 0.02 0.06 0.03 0.82ADFI,lb <0.01 <0.01 <0.01 0.48 0.05 0.13 0.08 0.82F/G <0.01 <0.01 <0.01 0.09 0.01 0.04 0.03 0.89d0to42  ADG,lb <0.01 <0.01 <0.01 0.92 <0.01 0.01 <0.01 0.55ADFI,lb 0.03 0.04 0.05 0.86 0.03 0.09 0.05 0.81F/G 0.01 0.01 0.01 0.96 0.02 0.09 0.02 0.55Weight,lb  d0 0.54 0.57 0.55 0.96 0.43 0.53 0.49 0.95d11 0.40 0.37 0.49 0.74 0.87 0.88 0.89 0.99d21 0.02 0.02 0.05 0.52 0.34 0.46 0.38 0.91d42 0.05 0.06 0.06 0.99 0.02 0.08 0.04 0.73Survival,% 0.03 0.06 0.04 0.74 0.89 0.61 0.79 0.48

continued

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Table 6. Statistical differences for performance and economic data, (P<)Contrasts1

1 2 3 4 5 6 7 8Feedcost,$/pigd0to11 <0.01 <0.01 <0.01 <0.01 0.01 0.09 0.01 0.37d11to21 <0.01 <0.01 <0.01 <0.01 <0.01 0.01 0.02 0.93d21to42 0.01 0.02 0.01 0.80 <0.01 <0.01 <0.01 0.47d0to21 <0.01 <0.01 <0.01 0.01 0.01 0.03 0.01 0.72d0to42 <0.01 <0.01 <0.01 0.22 <0.01 <0.01 <0.01 0.87Feedcost,$/lbgaind0to11 0.50 0.03 0.33 <0.01 0.32 0.21 0.70 0.42d11to21 0.24 <0.01 0.47 <0.01 0.99 0.74 0.72 0.53d21to42 0.08 0.05 0.19 0.28 <0.01 <0.01 0.14 0.03d0to21 0.27 <0.01 0.22 <0.01 0.85 0.80 0.94 0.88d0to42 0.04 0.34 <0.01 <0.01 0.02 0.01 0.34 0.08Incomeoverfeedcost1,$/pig2

d0to11 0.01 <0.01 0.24 <0.01 0.10 0.13 0.20 0.82d11to21 <0.01 <0.01 0.01 0.01 0.10 0.25 0.10 0.65d21to42 0.31 0.59 0.17 0.21 0.01 0.12 <0.01 0.17d0to21 <0.01 <0.01 0.01 <0.01 0.09 0.18 0.12 0.86d0to42 0.02 0.02 0.06 0.41 0.02 0.15 0.01 0.31Incomeoverfeedcost2,$/pig2

d0to11 <0.01 <0.01 0.01 0.04 0.03 0.08 0.07 0.96d11to21 <0.01 <0.01 <0.01 0.06 0.05 0.15 0.07 0.72d21to42 0.15 0.32 0.09 0.27 <0.01 0.02 <0.01 0.31d0to21 <0.01 <0.01 <0.01 0.03 0.04 0.11 0.07 0.83d0to42 0.01 0.01 0.02 0.70 0.01 0.05 0.01 0.441Contrast1=ResponsetoantibioticinPhases1and2(Treatment1vs.allothers).Contrast2=Denagard/CTCvs.nomedicationinPhases1and2(Treatments1vs.2,4,and6).Contrast3=Pulmotilvs.nomedicationinPhases1and2(Treatments1vs.3,5,and7).Contrast4=Denagard/CTCvs.Pulmotil(Treatments2,4,and6vs.3,5,and7).Contrast5=ResponsetoantibioticinPhase3(Treatments1,4,and5vs.2,3,6and7).Contrast6=Denagard/CTCvs.nomedicationinPhase3(Treatments1,4,and5vs.2and3).Contrast7=Mecadox/OTCvs.nomedicationinPhase3(Treatments1,4,and5vs.6and7).Contrast8=Denagard/CTCvs.Mecadox/OTCinPhase3(Treatments2and3vs.6and7).2Incomeoverfeedcost1assumedavalueofgainat$0.50/lb.Incomeoverfeedcost2assumedavalueofgainof$1.00/lb.